Big data size isn t enough! Irene Petersen, PhD Primary Care & Population Health

Size: px
Start display at page:

Download "Big data size isn t enough! Irene Petersen, PhD Primary Care & Population Health"

Transcription

1 Big data size isn t enough! Irene Petersen, PhD Primary Care & Population Health

2 Introduction Reader (Statistics and Epidemiology) Research team epidemiologists/statisticians/phd students Primary care databases THIN and CPRD studies Research topics Prescribed medicine in pregnancy Mental health Methodological questions Missing data Regression Discontinuity Design (RDD) Confounding (by indication) Cardiovascular diseases Infectious diseases Or just google THIN UCL

3 Today Big data - Electronic Health Records Safety and efficacy of medicine in real life Confounding and selection bias Potential solutions

4 Big Data - Electronic Health Records Primary Care Databases THIN, CPRD, QRESEARCH Administrative Databases Insurance claims databases Hospital Episodes Statistics Population registers Scandinavian registers

5 UK primary care databases (1) THIN, CPRD, Qresearch Anonymised records million years of patient data Medical diagnoses and symptoms, preventative measures, test results and immunisations, prescriptions, referrals to secondary care and free text information

6 UK primary care databases (2) Demographic information e.g. year of birth, sex, social deprivation (Townsend score) Broadly representative of the UK population (sex, age, size of practice and geographic distribution) For clinical management NOT for research

7 Electronic Health Records versus Randomised Controlled Trials Electronic Health Records Randomised Controlled Trials Data collection Clinical sessions At fixed time points Data Missing data Coded clinical records Read or ICD-10, measurements Well people have less data Interviews, questionnaires, measurements Random(?) Size Millions From hundreds to thousands Treatment Selective Randomised

8 Recording of weight by age and gender in THIN Age (years) Male Female

9 Recording of weight in diabetics and nondiabetics 80 measurement recorded weight Year measurement recorded Registered 1995 Registered 2000 Registered 2005 Registered 2010 solid line - diabetes, dashed line - no diabetes

10 Strength of Electronic Health Records Large sample sizes Population that is often difficult to follow up by other means Very elderly Pregnant women People with severe mental illnesses Real life data Long follow-up

11 Provide some fantastic opportunities! Explore effectiveness in populations not covered by RCTs Very elderly, pregnant, people with severe mental illnesses Examine adverse (drug) effects Bridge from RCT to real life

12 Before we get too excited. Let s look at some of the challenges and pitfalls

13 Case-control or Cohort study? Drug A is commonly prescribed Outcome B is rare Use electronic health records to address the question

14 88,125 cases and 362,254 matched controls Cases between 30 and 100 years 5 matched controls to be alive at the date of cancer Adjusted analysis for potential confounders such as smoking and social deprivation and some specific diseases

15 Prolonged use of statin (more than 4 years) Associated with significantly increased risk of: Colorectal cancer (OR 1.23, 95%CI 1.10 to 1.38) Bladder cancer (OR 1.29, 95%CI 1.08 to 1.54) Lung cancer (OR 1.18, 95%CI 1.05 to 1.34)

16 Hang on. Let s have a look at this again Cases were those who got cancer Controls were a random sample of those who were alive at the time the cases got cancer What if..

17 Those who receive prolonged statin treatment More likely to die from other causes than cancer (e.g. cardiovascular diseases)? Then they would be less likely to enter the control group

18 Case-control study with live controls Estimates sensitive to difference in survival rates between exposed and unexposed

19 Interpretation of case-control study cohort study Case-control study: Of the survivors what is the chance that those with cancer were exposed to statin? Cohort study: Of those exposed to statin what is the risks of developing cancer compared to those not exposed

20 Cohort study found no associations between statins and cancers Smeeth et al. British Journal of Clinical Pharmacology

21 Let s look at a few other examples

22 High dose antidepressants increase self harm in young people? Miller et al. JAMA Internal Medicine, April 2014

23 High dose antidepressants increase self harm in young people? Propensity score matched cohort study Health care utilization data from US residents Depression ages 10 to 64 years who initiated antidepressant therapy Standard (modal) versus higher doses

24 Propensity score methods Propensity Scores (PS) estimate the predicted probability (propensity) of use of a given drug PS based on his/her characteristics when the treatment is chosen logistic treatment sex age x1 x2 x3 x4 x5 x6 predict Predicted value (between 0-1) is the propensity score

25 Propensity scores Sturmer et al. J Clin Epidemiol May ; 59(5): Williamson et al. Statistical Methods in Medical Research (3)

26 High dose antidepressants increase self harm in young people? High versus modal dose in young people: hazard ratio [HR], 2.2 [95%CI, ] 1 additional event for every 150 such patients treated with high-dose (instead of modal-dose) therapy High versus model dose in adults (25 64 years): HR, 1.2 [95%CI, ]

27 Conclusions and implication Children and young adults. at hightherapeutic (rather than modal-therapeutic) doses seem to be at heightened risk of deliberate self-harm. Our findings offer clinicians an additional incentive to avoid initiating pharmacotherapy at high-therapeutic doses.

28

29 What is the problem?

30 Health care data Randomised Controlled Trial Propensity score methods may balance measured characteristics but. Propensity score methods may NOT balance unmeasured characteristics

31 Not just random allocation Clinicians make a treatment decision Acute presentation of psychiatric illness Severe ill individuals may receive higher doses This information is NOT captured in the health care databases

32 Confounding by indication Acute and severe psychiatric problem High dose antidepressant self harm

33 Confounding by indication Acute and severe psychiatric problem High dose antidepressant self harm

34 High dose antidepressant A mere marker of acute severe psychiatric problems Underlying condition associated with increased self-harm? Too early to conclude that high doses of antidepressants are unsafe Leave young people without treatment!?

35 Efficacy of heart failure treatment in real life? An example from our own work

36 Spironolactone treatment for heart failure Spironolactone improve survival in people with heart failure in Randomised Controlled Trials What about in real life?

37 RALES trial - NEJM September 1999 The trial was discontinued early, after 24 months Spironolactone was efficacious 386 deaths in the placebo group (46%) 284 in the spironolactone group (35%) Relative risk of death: Hazard Ratio: 0.70 (95% CI, 0.60 to 0.82; P<0.001)

38 Bridge from RCT to real life Identified people with severe heart failure in THIN Propensity score for spironolactone treatment Matched individuals with and without treatment Estimated relative survival using a Cox model

39 What did we find? People treated with spironolactone had same chance of survival after 24 months as those treated in RALES trial People with heart failure, but NOT treated, had an even better survival!

40 Relative risk of mortality in people treated with spironolactone RALES: Hazard Ratio: 0.70 (95% CI ) Our study: Hazard Ratio: 1.32 (95% CI ) Freemantle et al. BMJ 2013

41 Similar problem as before. Treatment is NOT randomly allocated Doctors make a choice Spironolactone given to those with worse prognosis More severe heart failure Acute situation? Reason for prescribing was NOT recorded Propensity score cannot solve the issue of confounding by indication

42

43 Bridge from Randomised Controlled Trials to real life - Statin example Propensity score matched sample This time, they were able to replicate trial results!

44 Why was it possible in this situation? Statin was used as primary prevention, rather than treatment of illness Potential confounders were captured in data Weight, blood pressure, sex, deprivation etc.

45 Propensity Scores and other regression adjustments may. It may work when Treatment is given as prevention and data is recorded in the database (e.g. statin) Decision to treat unrelated to prognosis of outcome (unexpected effects) It may NOT work when treatment is given in response to acute clinical need or people who are more frail (e.g.antidepressant, spironolactone, hypnotics)

46 The future for analysis and design of BIG data studies Cohort rather case-control studies Still need to think design through carefully Cohort studies including Several comparison groups Active comparisons e.g. drug versus drug Sequential simulated trials Self-controlled case series (SCCS) Instrumental Variables Regression Discontinuation Design

47 The future for analysis and design of BIG data studies (2) Sequential Simulated trials Run series of trials in database Trial 1: those initiated on treatment in 2001 versus those not initiated in 2001 Trial 2: those initiated on treatment in 2002 versus those not initiated in 2002 Danaei et al Toh & Manson 2013

48 The future for analysis and design of BIG data studies (3) Sequential Simulated trials Avoid selection based on the future Less likely to have a healthy user or healthy non-user effect Makes is easy to define start for non-exposed

49 The future for analysis and design of BIG data studies (4) Self-controlled case series (SCCS) methodology Use individuals as their own control See

50 The future for analysis and design of BIG data studies (4) Instrumental variables Use variation among general practices?

51 Summary Electronic Health Records reflect real life clinical practice Randomised Controlled Trials Confounding (by indication) and selection bias still are major issues! - think about the study design Interpretation of results Offer more than one interpretation perhaps drug is just a marker? Accept the limitations of BIG data

52

53 References 1. Freemantle N, Marston L, Walters K, Wood J, Reynolds MR, Petersen I. Making inferences on treatment effects from real world data: propensity scores, confounding by indication, and other perils for the unwary in observational research. BMJ Nov 11;347(nov11 3):f6409 f Williamson E, Morley R, Lucas A, Carpenter J. Propensity scores: From naive enthusiasm to intuitive understanding. Stat Methods Med Res Jun 1;21(3): Stürmer T, Joshi M, Glynn RJ, Avorn J, Rothman KJ, Schneeweiss S. A review of the application of propensity score methods yielded increasing use, advantages in specific settings, but not substantially different estimates compared with conventional multivariable methods. J Clin Epidemiol May;59(5): Rosenbaum PR, Rubin DB. The Central Role of the Propensity Score in Observational Studies for Causal Effects. Biometrika Apr;70(1): Miller M, Swanson SA, Azrael D, Pate V, Stürmer T. Antidepressant Dose, Age, and the Risk of Deliberate Self-harm. JAMA Intern Med [Internet] Apr 28 [cited 2014 May 1]; Available from: 6. Smeeth L, Douglas I, Hall AJ, Hubbard R, Evans S. Effect of statins on a wide range of health outcomes: a cohort study validated by comparison with randomized trials. Br J Clin Pharmacol Jan;67(1): Toh S, Manson JE. An Analytic Framework for Aligning Observational and Randomized Trial Data: Application to Postmenopausal Hormone Therapy and Coronary Heart Disease. Stat Biosci Nov;5(2): Whitaker HJ, Paddy Farrington C, Spiessens B, Musonda P. Tutorial in biostatistics: the self-controlled case series method. Stat Med. 2006;25(10):

Randomized trials versus observational studies

Randomized trials versus observational studies Randomized trials versus observational studies The case of postmenopausal hormone therapy and heart disease Miguel Hernán Harvard School of Public Health www.hsph.harvard.edu/causal Joint work with James

More information

With Big Data Comes Big Responsibility

With Big Data Comes Big Responsibility With Big Data Comes Big Responsibility Using health care data to emulate randomized trials when randomized trials are not available Miguel A. Hernán Departments of Epidemiology and Biostatistics Harvard

More information

Safety & Effectiveness of Drug Therapies for Type 2 Diabetes: Are pharmacoepi studies part of the problem, or part of the solution?

Safety & Effectiveness of Drug Therapies for Type 2 Diabetes: Are pharmacoepi studies part of the problem, or part of the solution? Safety & Effectiveness of Drug Therapies for Type 2 Diabetes: Are pharmacoepi studies part of the problem, or part of the solution? IDEG Training Workshop Melbourne, Australia November 29, 2013 Jeffrey

More information

Today. Observational Study Designs. Study Designs

Today. Observational Study Designs. Study Designs Today Observational Study Designs What and why on observational studies Measures of disease occurrence Prevalence Incidence Denise Boudreau, PhD Center for Health Studies Group Health Cooperative Cohort

More information

Guide to Biostatistics

Guide to Biostatistics MedPage Tools Guide to Biostatistics Study Designs Here is a compilation of important epidemiologic and common biostatistical terms used in medical research. You can use it as a reference guide when reading

More information

Subgroup analysis when using the propensity score

Subgroup analysis when using the propensity score Subgroup analysis when using the propensity score Hester van Eeren 1,3, Marieke D. Spreeuwenberg 2, Janine G. van Manen 3,6, Mark de Rooij 4, Theo Stijnen 5, & Jan J.V. Busschbach 1,3 Institutional affiliation

More information

Statistical models for vaccines using. propensity score. Aksel Jensen 1,2. What is a. propensity. score? Why use a. propensity. score?

Statistical models for vaccines using. propensity score. Aksel Jensen 1,2. What is a. propensity. score? Why use a. propensity. score? 1 / 10 1 CVIVA, Research Center For Vitamins & Vaccines, Statens Serum Institut. 2 Department of Biostatistics, University of Copenhagen. 2 / 10 Outline How can a be used? What are the challenges in the

More information

Lessons about Confounding and Selection Bias Taught by the New User Design. Conflict of Interest. Outline

Lessons about Confounding and Selection Bias Taught by the New User Design. Conflict of Interest. Outline Lessons about Confounding and Selection Bias Taught by the New User Design Til Stürmer, FISPE UNC Gillings School of Global Public Health University of North Carolina at Chapel Hill, USA Conflict of Interest

More information

Objectives. Who faces a higher mortality from cardiovascular related illness? Epidemiology of CVD. Cardiovascular Disease Management in Women

Objectives. Who faces a higher mortality from cardiovascular related illness? Epidemiology of CVD. Cardiovascular Disease Management in Women Cardiovascular Disease Management in Objectives. Epidemiology 2. Risk Stratification 3. Depression Screening in 4. Aspirin Use in 5. Summary Lisa Ward, MD, MSPH, MS Associate Clinical Professor Santa Rosa

More information

EPIDEMIOLOGY-BIOSTATISTICS Exam 1, 2005

EPIDEMIOLOGY-BIOSTATISTICS Exam 1, 2005 EPIDEMIOLOGY-BIOSTATISTICS Exam 1, 2005 Print Your Legal Name: ID Number: Instructions: This exam is 25% of your course grade. The maximum number of points for the course is 1,000 hence this exam is worth

More information

PROMISE & PITFALLS OF OUTCOMES RESEARCH USING EMR DATABASES. Richard L. Tannen, M.D., Mark Weiner, Dawei Xie

PROMISE & PITFALLS OF OUTCOMES RESEARCH USING EMR DATABASES. Richard L. Tannen, M.D., Mark Weiner, Dawei Xie PROMISE & PITFALLS OF OUTCOMES RESEARCH USING EMR DATABASES Richard L. Tannen, M.D., Mark Weiner, Dawei Xie GOALS OF STUDY Determine Whether Studies Using EMR Database Yield Valid Outcome Assessment Major

More information

Hypoglycemia as a risk factor for cardiovascular disease and mortality

Hypoglycemia as a risk factor for cardiovascular disease and mortality Hypoglycemia as a risk factor for cardiovascular disease and mortality Dong-Jun Kim, M.D.,PhD. Department of Internal Medicine, Inje University College of Medicine Hypoglycemia: the most important complication

More information

Overview of Main Quantitative Research Strategies. Epidemiology. Epidemiological methods. The study of the distribution and

Overview of Main Quantitative Research Strategies. Epidemiology. Epidemiological methods. The study of the distribution and Overview of Main Quantitative Research Strategies In this session we will consider: what questions can be answered using quantitative research methods the classification of study types used in epidemiological

More information

Methods to control for confounding - Unmeasured confounding - 18 February 2015

Methods to control for confounding - Unmeasured confounding - 18 February 2015 Methods to control for confounding - Unmeasured confounding - 18 February 2015 Objectives At the end of this session about unmeasured confounding, you will be able to: Recognize sources of unmeasured confounding

More information

Bias in clinical trials. Małgorzata Bała

Bias in clinical trials. Małgorzata Bała Bias in clinical trials Małgorzata Bała malgorzata.1.bala@uj.edu.pl Warsaw, 2015 1 What is bias? 2 What is bias? Random error Systematic error (bias) 3 Bias a systematic error a systematic disposition

More information

METHODOLOGY 101 Training For Patients and Stakeholders Training Booklet & Resource Guide

METHODOLOGY 101 Training For Patients and Stakeholders Training Booklet & Resource Guide METHODOLOGY 101 Training For Patients and Stakeholders Training Booklet & Resource Guide V2 December, 2014 PCORI METHODOLOGY 101 TRAINING BOOKLET AND RESOURCE GUIDE 1 Methodology 101 Training Booklet and

More information

Always Start with PECO

Always Start with PECO Goals of This Course Be able to understand a study design (very basic concept) Be able to understand statistical concepts in a medical paper Be able to perform a data analysis Understanding: PECO study

More information

What are observational studies and how do they differ from clinical trials?

What are observational studies and how do they differ from clinical trials? What are observational studies and how do they differ from clinical trials? Caroline A. Sabin Dept. Infection and Population Health UCL, Royal Free Campus London, UK Experimental/observational studies

More information

Komorbide brystkræftpatienter kan de tåle behandling? Et registerstudie baseret på Danish Breast Cancer Cooperative Group

Komorbide brystkræftpatienter kan de tåle behandling? Et registerstudie baseret på Danish Breast Cancer Cooperative Group Komorbide brystkræftpatienter kan de tåle behandling? Et registerstudie baseret på Danish Breast Cancer Cooperative Group Lotte Holm Land MD, ph.d. Onkologisk Afd. R. OUH Kræft og komorbiditet - alle skal

More information

Missing data and net survival analysis Bernard Rachet

Missing data and net survival analysis Bernard Rachet Workshop on Flexible Models for Longitudinal and Survival Data with Applications in Biostatistics Warwick, 27-29 July 2015 Missing data and net survival analysis Bernard Rachet General context Population-based,

More information

Research Skills for Non-Researchers: Using Electronic Health Data and Other Existing Data Resources

Research Skills for Non-Researchers: Using Electronic Health Data and Other Existing Data Resources Research Skills for Non-Researchers: Using Electronic Health Data and Other Existing Data Resources James Floyd, MD, MS Sep 17, 2015 UW Hospital Medicine Faculty Development Program Objectives Become more

More information

Big Data Health Big Health Improvements? Dr Kerry Bailey MBBS BSc MSc MRCGP FFPH Dr Kelly Nock MPhys PhD

Big Data Health Big Health Improvements? Dr Kerry Bailey MBBS BSc MSc MRCGP FFPH Dr Kelly Nock MPhys PhD Big Data Health Big Health Improvements? Dr Kerry Bailey MBBS BSc MSc MRCGP FFPH Dr Kelly Nock MPhys PhD Epidemiology Infection 2006 Dec;134(6):1167-73. Epub 2006 Apr 20. Risk factors for hospital-acquired

More information

WH RESEARCH TRAINING WORKSHOP 2013 Date: Thursdays,12:30-1:30pm Venue: Auditorium Western Centre for Health Research & Education Sunshine Hospital

WH RESEARCH TRAINING WORKSHOP 2013 Date: Thursdays,12:30-1:30pm Venue: Auditorium Western Centre for Health Research & Education Sunshine Hospital WH RESEARCH TRAINING WORKSHOP 2013 Date: Thursdays,12:30-1:30pm Venue: Auditorium Western Centre for Health Research & Education Sunshine Hospital Workshop Topic Presenters Date Research Ethics & Governance

More information

New Cholesterol Guidelines: Carte Blanche for Statin Overuse Rita F. Redberg, MD, MSc Professor of Medicine

New Cholesterol Guidelines: Carte Blanche for Statin Overuse Rita F. Redberg, MD, MSc Professor of Medicine New Cholesterol Guidelines: Carte Blanche for Statin Overuse Rita F. Redberg, MD, MSc Professor of Medicine Disclosures & Relevant Relationships I have nothing to disclose No financial conflicts Editor,

More information

Medical statistics. Lecture 2: Types of medical studies. Krista Fischer

Medical statistics. Lecture 2: Types of medical studies. Krista Fischer Medical statistics Lecture 2: Types of medical studies. Krista Fischer The evidence pyramid Motivated by: http://library.downstate.edu/ebm/2100.htm Clinical research, providing results that are relevant

More information

Drug discontinuation and switching during the Medicare Part D coverage gap

Drug discontinuation and switching during the Medicare Part D coverage gap Drug discontinuation and switching during the Medicare Part D coverage gap Jennifer M. Polinski, ScD, MPH William H. Shrank, MD, MSHS; Haiden A. Huskamp, PhD; Robert J. Glynn, PhD, ScD; Joshua N. Liberman,

More information

Prevalence of ischaemic heart disease and its management with statins and aspirin in general practice in England and Wales, 1994 and1998

Prevalence of ischaemic heart disease and its management with statins and aspirin in general practice in England and Wales, 1994 and1998 Prevalence of ischaemic heart disease and its management with statins and aspirin in general practice in England and Wales, 1994 and1998 Ronan Ryan, Office for National Statistics Azeem Majeed, School

More information

Can we establish cause-and-effect relationships in large healthcare databases?

Can we establish cause-and-effect relationships in large healthcare databases? Can we establish cause-and-effect relationships in large healthcare databases? Lawrence McCandless Associate Professor lmccandl@sfu.ca Faculty of Health Sciences, Simon Fraser University Spring 2016 Example

More information

Hormones and cardiovascular disease, what the Danish Nurse Cohort learned us

Hormones and cardiovascular disease, what the Danish Nurse Cohort learned us Hormones and cardiovascular disease, what the Danish Nurse Cohort learned us Ellen Løkkegaard, Clinical Associate Professor, Ph.d. Dept. Obstetrics and Gynecology. Hillerød Hospital, University of Copenhagen

More information

Neal Rouzier responds to the JAMA article on Men and Testosterone

Neal Rouzier responds to the JAMA article on Men and Testosterone Neal Rouzier responds to the JAMA article on Men and Testosterone On the first day the JAMA article was released I received 500 emails from physicians and patients requesting my opinion of the article

More information

Comparative effectiveness between bisoprolol and metoprolol succinate among patients with heart failure

Comparative effectiveness between bisoprolol and metoprolol succinate among patients with heart failure Comparative effectiveness between bisoprolol and metoprolol succinate among patients with heart failure Author: Anders Mattsson, MD Department of internal medicine, Visby Hospital Research supervisor:

More information

The Impact of Obesity on Cancer Survivorship

The Impact of Obesity on Cancer Survivorship The Impact of Obesity on Cancer Survivorship Leslie Bernstein, Ph.D. Professor and Director, Division of Cancer Etiology Department of Population Sciences Beckman Research Institute City of Hope Measuring

More information

AMBREEN RAZA MBBS VARUN MALAYALA MBBS, MPH. University at Buffalo/Sisters of Charity Hospital

AMBREEN RAZA MBBS VARUN MALAYALA MBBS, MPH. University at Buffalo/Sisters of Charity Hospital AMBREEN RAZA MBBS VARUN MALAYALA MBBS, MPH University at Buffalo/Sisters of Charity Hospital Conflict of interest: None Financial disclosures: None United States Preventive Services Taskforce (USPSTF)

More information

If several different trials are mentioned in one publication, the data of each should be extracted in a separate data extraction form.

If several different trials are mentioned in one publication, the data of each should be extracted in a separate data extraction form. General Remarks This template of a data extraction form is intended to help you to start developing your own data extraction form, it certainly has to be adapted to your specific question. Delete unnecessary

More information

26/09/2015. Agenda. Background. Overprescribing of statin for primary prevention especially for women? Statins for primary prevention, evidence based?

26/09/2015. Agenda. Background. Overprescribing of statin for primary prevention especially for women? Statins for primary prevention, evidence based? 26/9/215 Faculty c u l ty of o f Helth Heal th and a nd Medical M e al Sciences S c ce s Agenda Initiation of statin therapy for primary prevention: Overprescribing in postmenopausal women with hypercholesterolemia?

More information

Understanding Evidence-Based Healthcare: A Foundation for Action Module 3: ALIGN. Research Design, Bias, and Levels of Evidence Musa Mayer, MS, MFA

Understanding Evidence-Based Healthcare: A Foundation for Action Module 3: ALIGN. Research Design, Bias, and Levels of Evidence Musa Mayer, MS, MFA Section G HRT: The Women s Health Initiative Advocates Speak Out Menopause is not a disease. So why are millions of American women taking a drug for this natural body process? The widespread popularity

More information

Cardiovascular disease (CVD) is the leading cause of death in women, accounting for 54% of deaths in women in Europe

Cardiovascular disease (CVD) is the leading cause of death in women, accounting for 54% of deaths in women in Europe Red Alert for Women s Hearts Summary FACTS ON WOMEN AND CARDIOVASCULAR RESEARCH Cardiovascular disease (CVD) is the leading cause of death in women, accounting for 54% of deaths in women in Europe Women

More information

Estrogen Alone and Health Outcomes in Black Women by African Ancestry

Estrogen Alone and Health Outcomes in Black Women by African Ancestry Estrogen Alone and Health Outcomes in Black Women by African Ancestry Wendy E. Barrington, PhD, MPH Rowan T. Chlebowski, Aaron K. Aragaki, JoAnn E. Manson, Gloria Sarto, Mary J. O Sullivan, Jane A. Cauley,

More information

An Application of the G-formula to Asbestos and Lung Cancer. Stephen R. Cole. Epidemiology, UNC Chapel Hill. Slides: www.unc.

An Application of the G-formula to Asbestos and Lung Cancer. Stephen R. Cole. Epidemiology, UNC Chapel Hill. Slides: www.unc. An Application of the G-formula to Asbestos and Lung Cancer Stephen R. Cole Epidemiology, UNC Chapel Hill Slides: www.unc.edu/~colesr/ 1 Acknowledgements Collaboration with David B. Richardson, Haitao

More information

Key Components of the Research Question PICOT

Key Components of the Research Question PICOT Key Components of the Research Question PICOT CONTEXT: Low birth weight is implicated as a risk factor for type 2 diabetes. However, the strength, consistency, independence, and shape of the association

More information

Study Design STUDY DESIGN CASE SERIES AND CROSS-SECTIONAL STUDY DESIGN STUDY DESIGNS AND CORRESPONDING QUESTIONS

Study Design STUDY DESIGN CASE SERIES AND CROSS-SECTIONAL STUDY DESIGN STUDY DESIGNS AND CORRESPONDING QUESTIONS STUDY DESIGN CASE SERIES AND CROSS-SECTIONAL Daniel E. Ford, MD, MPH Vice Dean for Clinical Investigation Johns Hopkins School of Medicine Introduction to Clinical Research STUDY DESIGN Provides differential

More information

Vitamin D and Calcium in Midlife Women

Vitamin D and Calcium in Midlife Women Vitamin D and Calcium in Midlife Women JoAnn E. Manson, MD, DrPH, NCMP Chief, Division of Preventive Medicine Brigham and Women's Hospital Professor of Medicine and the Michael and Lee Bell Professor of

More information

Introduction to study design

Introduction to study design Introduction to study design Doug Altman EQUATOR Network, Centre for Statistics in Medicine, NDORMS, University of Oxford EQUATOR OUCAGS training course 4 October 2014 Objectives of the day To understand

More information

SECOND M.B. AND SECOND VETERINARY M.B. EXAMINATIONS INTRODUCTION TO THE SCIENTIFIC BASIS OF MEDICINE EXAMINATION. Friday 14 March 2008 9.00-9.

SECOND M.B. AND SECOND VETERINARY M.B. EXAMINATIONS INTRODUCTION TO THE SCIENTIFIC BASIS OF MEDICINE EXAMINATION. Friday 14 March 2008 9.00-9. SECOND M.B. AND SECOND VETERINARY M.B. EXAMINATIONS INTRODUCTION TO THE SCIENTIFIC BASIS OF MEDICINE EXAMINATION Friday 14 March 2008 9.00-9.45 am Attempt all ten questions. For each question, choose the

More information

Measures of disease frequency

Measures of disease frequency Measures of disease frequency Madhukar Pai, MD, PhD McGill University, Montreal Email: madhukar.pai@mcgill.ca 1 Overview Big picture Measures of Disease frequency Measures of Association (i.e. Effect)

More information

Big Healthcare Data: How the UK is leading the way

Big Healthcare Data: How the UK is leading the way Big Healthcare Data: How the UK is leading the way Maggie Massam Head of Business Development Clinical Practice Research Datalink December 2014 The world s best primary care data Single payer system cradle

More information

Epidemiology-Biostatistics Exam Exam 1, 2001 PRINT YOUR LEGAL NAME:

Epidemiology-Biostatistics Exam Exam 1, 2001 PRINT YOUR LEGAL NAME: Epidemiology-Biostatistics Exam Exam 1, 2001 PRINT YOUR LEGAL NAME: Instructions: This exam is 25% of your course grade. The maximum number of points for the course is 1,000; hence this exam is worth 250

More information

Informatics: Opportunities & Applications. Professor Colin McCowan Robertson Centre for Biostatistics and Glasgow Clinical Trials Unit

Informatics: Opportunities & Applications. Professor Colin McCowan Robertson Centre for Biostatistics and Glasgow Clinical Trials Unit Informatics: Opportunities & Applications Professor Colin McCowan Robertson Centre for Biostatistics and Glasgow Clinical Trials Unit Routine Data "routine data" is data collected as byproducts of clinical

More information

Epidemiology-Biostatistics Exam Exam 2, 2001 PRINT YOUR LEGAL NAME:

Epidemiology-Biostatistics Exam Exam 2, 2001 PRINT YOUR LEGAL NAME: Epidemiology-Biostatistics Exam Exam 2, 2001 PRINT YOUR LEGAL NAME: Instructions: This exam is 30% of your course grade. The maximum number of points for the course is 1,000; hence this exam is worth 300

More information

Measure #257 (NQF 1519): Statin Therapy at Discharge after Lower Extremity Bypass (LEB) National Quality Strategy Domain: Effective Clinical Care

Measure #257 (NQF 1519): Statin Therapy at Discharge after Lower Extremity Bypass (LEB) National Quality Strategy Domain: Effective Clinical Care Measure #257 (NQF 1519): Statin Therapy at Discharge after Lower Extremity Bypass (LEB) National Quality Strategy Domain: Effective Clinical Care 2016 PQRS OPTIONS FOR INDIVIDUAL MEASURES: REGISTRY ONLY

More information

Confounding in health research

Confounding in health research Confounding in health research Part 1: Definition and conceptual issues Madhukar Pai, MD, PhD Assistant Professor of Epidemiology McGill University madhukar.pai@mcgill.ca 1 Why is confounding so important

More information

Self-controlled Case Series (SCCS), the basics. Irene Petersen, PhD Senior Lecturer (Epidemiology and Statistics) Primary Care and Population Health

Self-controlled Case Series (SCCS), the basics. Irene Petersen, PhD Senior Lecturer (Epidemiology and Statistics) Primary Care and Population Health Self-controlled Case Series (SCCS), the basics Irene Petersen, PhD Senior Lecturer (Epidemiology and Statistics) Primary Care and Population Health Acknowledgements Paddy Farrington Heather Whitaker Open

More information

Why is benefit-to-harm balance essential to treatment decisions?

Why is benefit-to-harm balance essential to treatment decisions? Chapter 2 Why is benefit-to-harm balance essential to treatment decisions? The 1962 amendments to the U.S. Federal Food, Drug and Cosmetic Act require that for a new drug to be approved for marketing,

More information

MOH CLINICAL PRACTICE GUIDELINES 6/2011 DEPRESSION

MOH CLINICAL PRACTICE GUIDELINES 6/2011 DEPRESSION MOH CLINICAL PRACTICE GUIDELINES 6/2011 DEPRESSION Executive summary of recommendations Details of recommendations can be found in the main text at the pages indicated. Clinical evaluation D The basic

More information

A list of FDA-approved testosterone products can be found by searching for testosterone at http://www.accessdata.fda.gov/scripts/cder/drugsatfda/.

A list of FDA-approved testosterone products can be found by searching for testosterone at http://www.accessdata.fda.gov/scripts/cder/drugsatfda/. FDA Drug Safety Communication: FDA cautions about using testosterone products for low testosterone due to aging; requires labeling change to inform of possible increased risk of heart attack and stroke

More information

Cohort Studies. ISPE Midyear Meeting 2013 Introduction to Pharmacoepidemiology. Conflict of Interest

Cohort Studies. ISPE Midyear Meeting 2013 Introduction to Pharmacoepidemiology. Conflict of Interest ISPE Midyear Meeting 2013 Introduction to Pharmacoepidemiology Cohort Studies Almut G. Winterstein, RPh, PhD Pharmaceutical Outcomes & Policy, College of Pharmacy Epidemiology, Colleges of Medicine & Public

More information

Critical Appraisal of a Randomized Controlled Trial Are the Results of the Study Valid?

Critical Appraisal of a Randomized Controlled Trial Are the Results of the Study Valid? Critical Appraisal of a Randomized Controlled Trial Are the Results of the Study Valid? Objectives: 1. Compare and contrast observational and experimental studies. 2. Define study population and inclusion

More information

Case-Control Studies. Sukon Kanchanaraksa, PhD Johns Hopkins University

Case-Control Studies. Sukon Kanchanaraksa, PhD Johns Hopkins University This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike License. Your use of this material constitutes acceptance of that license and the conditions of use of materials on this

More information

Long-term adherence to statins and outcome after acute myocardial infarction: A nationwide French survey of administrative data.

Long-term adherence to statins and outcome after acute myocardial infarction: A nationwide French survey of administrative data. Long-term adherence to statins and outcome after acute myocardial infarction: A nationwide French survey of administrative data. Anke Neumann, PhD, Philippe Tuppin, MD, Nicolas Danchin, MD, Christine De

More information

COHORT STUDIES. Concept of a cohort : A group of individuals that are all similar in some trait and move forward together as a unit.

COHORT STUDIES. Concept of a cohort : A group of individuals that are all similar in some trait and move forward together as a unit. OCW Epidemiology and Biostatistics, 2010 Alice Tang Tufts University School of Medicine October 5, 2010 COHORT STUDIES Learning objectives for this session: 1) Know when it is appropriate/feasible to use

More information

RESEARCH GUIDELINES 1. Consider the research hypothesis: 2. Consider the design of the study: 3. Consider the outcome variable:

RESEARCH GUIDELINES 1. Consider the research hypothesis: 2. Consider the design of the study: 3. Consider the outcome variable: RESEARCH GUIDELINES 1. Consider the research hypothesis: a) Is there a clear statement of the research hypothesis? b) Does the study address a question that has clinical relevance? 2. Consider the design

More information

Outline. Clinical Characteristics VA N=13, Midwest N=57,864. Northeast N=39,405. South N=63,137.

Outline. Clinical Characteristics VA N=13, Midwest N=57,864. Northeast N=39,405. South N=63,137. Outline Heart Failure in the Nursing Home Evelyn Hutt MD Geriatric Grand Rounds University of Colorado Denver January 2011 Prevalence and demographics Clinical characteristics Outcomes Preserved versus

More information

Introduction to epidemiology and study designs. Janusz Kaczorowski PhD University of British Columbia

Introduction to epidemiology and study designs. Janusz Kaczorowski PhD University of British Columbia Introduction to epidemiology and study designs Janusz Kaczorowski PhD University of British Columbia What is epidemiology? Epidemiology is the study of factors affecting the health and illness of populations

More information

Biostatistics and Epidemiology within the Paradigm of Public Health. Sukon Kanchanaraksa, PhD Marie Diener-West, PhD Johns Hopkins University

Biostatistics and Epidemiology within the Paradigm of Public Health. Sukon Kanchanaraksa, PhD Marie Diener-West, PhD Johns Hopkins University This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike License. Your use of this material constitutes acceptance of that license and the conditions of use of materials on this

More information

Why are men at increased risk of depression compared to women in palliative care?

Why are men at increased risk of depression compared to women in palliative care? Why are men at increased risk of depression compared to women in palliative care? William Lee, Richard Hayes, Lauren Rayner, Annabel Price, Matthew Hotopf Background Depression is more common in the palliative

More information

SULFONYLUREA USE AND RISK OF HIP FRACTURES AMONG ELDERLY MEN AND WOMEN WITH TYPE 2 DIABETES

SULFONYLUREA USE AND RISK OF HIP FRACTURES AMONG ELDERLY MEN AND WOMEN WITH TYPE 2 DIABETES SULFONYLUREA USE AND RISK OF HIP FRACTURES AMONG ELDERLY MEN AND WOMEN WITH TYPE 2 DIABETES Swapnil N. Rajpathak 1, Chunmay Fu 1, Kimberly G. Brodovicz 1, Samuel S. Engel 1, Kate Lapane 2 1 Merck Sharp

More information

OUTCOMES RESEARCH USING A LEARNING HEALTH SYSTEM: PROMISE & PITFALLS

OUTCOMES RESEARCH USING A LEARNING HEALTH SYSTEM: PROMISE & PITFALLS OUTCOMES RESEARCH USING A LEARNING HEALTH SYSTEM: PROMISE & PITFALLS Richard L. Tannen, M.D. University of Pennsylvania Perelman School of Medicine KFF director of Medical research u More than a decade

More information

Propensity score. Per Kragh Andersen, Biostatistisk Afdeling, KU. Dansk Selskab for Farmakoepidemiologi,

Propensity score. Per Kragh Andersen, Biostatistisk Afdeling, KU. Dansk Selskab for Farmakoepidemiologi, Propensity score Per Kragh Andersen, Biostatistisk Afdeling, KU Dansk Selskab for Farmakoepidemiologi, 16-11-2010 Introduction (Rosenbaum and Rubin, 1983); average causal effect vs. conditional effect

More information

GRIP STRENGTH AS A MARKER FOR DIABETES RISK? Luke Wander, R2 Internal Medicine

GRIP STRENGTH AS A MARKER FOR DIABETES RISK? Luke Wander, R2 Internal Medicine GRIP STRENGTH AS A MARKER FOR DIABETES RISK? Luke Wander, R2 Internal Medicine BACKGROUND Diabetes risk factors 1 : Age Obesity Fat distribution Birth weight Ethnicity Lack of exercise Family history Smoking

More information

EXPANDING THE EVIDENCE BASE IN OUTCOMES RESEARCH: USING LINKED ELECTRONIC MEDICAL RECORDS (EMR) AND CLAIMS DATA

EXPANDING THE EVIDENCE BASE IN OUTCOMES RESEARCH: USING LINKED ELECTRONIC MEDICAL RECORDS (EMR) AND CLAIMS DATA EXPANDING THE EVIDENCE BASE IN OUTCOMES RESEARCH: USING LINKED ELECTRONIC MEDICAL RECORDS (EMR) AND CLAIMS DATA A CASE STUDY EXAMINING RISK FACTORS AND COSTS OF UNCONTROLLED HYPERTENSION ISPOR 2013 WORKSHOP

More information

Diet and Cancer: Evaluating the Quality of the Evidence

Diet and Cancer: Evaluating the Quality of the Evidence Diet and Cancer: Evaluating the Quality of the Evidence Kevin C. Maki, PhD, CLS, FNLA, FTOS, FACN MB Clinical Research & DePaul University Chicago, IL Evidence-based Medicine An approach to the development

More information

Intervention and clinical epidemiological studies

Intervention and clinical epidemiological studies Intervention and clinical epidemiological studies Including slides from: Barrie M. Margetts Ian L. Rouse Mathew J. Reeves,PhD Dona Schneider Tage S. Kristensen Victor J. Schoenbach Experimental / intervention

More information

Basic Study Designs in Analytical Epidemiology For Observational Studies

Basic Study Designs in Analytical Epidemiology For Observational Studies Basic Study Designs in Analytical Epidemiology For Observational Studies Cohort Case Control Hybrid design (case-cohort, nested case control) Cross-Sectional Ecologic OBSERVATIONAL STUDIES (Non-Experimental)

More information

GHQ SCORES PREDICT UNIQUELY SUBSEQUENT SURVIVAL IN SUCCESSFULLY TREATED HEAD AND NECK CANCER PATIENTS: A PROSPECTIVE COHORT STUDY

GHQ SCORES PREDICT UNIQUELY SUBSEQUENT SURVIVAL IN SUCCESSFULLY TREATED HEAD AND NECK CANCER PATIENTS: A PROSPECTIVE COHORT STUDY GHQ SCORES PREDICT UNIQUELY SUBSEQUENT SURVIVAL IN SUCCESSFULLY TREATED HEAD AND NECK CANCER PATIENTS: A PROSPECTIVE COHORT STUDY Anne K.H. Aarstad 2,3, Arild A Osthus 1, Jan Olofsson 1,2, Hans J. Aarstad

More information

EBM Cheat Sheet- Measurements Card

EBM Cheat Sheet- Measurements Card EBM Cheat Sheet- Measurements Card Basic terms: Prevalence = Number of existing cases of disease at a point in time / Total population. Notes: Numerator includes old and new cases Prevalence is cross-sectional

More information

The direct costs to the NHS of discontinuing and switching prescriptions for hypertension

The direct costs to the NHS of discontinuing and switching prescriptions for hypertension Journal of Human Hypertension (1998) 12, 533 537 1998 Stockton Press. All rights reserved 0950-9240/98 $12.00 http://www.stockton-press.co.uk/jhh ORIGINAL ARTICLE The direct costs to the NHS of discontinuing

More information

Study Design for Chemoprevention. Cancer Epidemiology, Prevention and Control Workshop Shanghai, March 12, 2008

Study Design for Chemoprevention. Cancer Epidemiology, Prevention and Control Workshop Shanghai, March 12, 2008 Study Design for Chemoprevention Cancer Epidemiology, Prevention and Control Workshop Shanghai, March 12, 2008 I. INTRODUCTION Experimental studies are conducted to assess the effect of a treatment using

More information

A Guide to Clinical Trials

A Guide to Clinical Trials A Guide to Clinical Trials For young people with cancer and their parents Children s Cancer and Leukaemia Group www.cclg.org.uk Original booklet produced in conjunction with the CCLG Patient Advocacy Committee.

More information

This supplementary material has been provided by the authors to give readers additional information about their work.

This supplementary material has been provided by the authors to give readers additional information about their work. SUPPLEMENTAL MATERIAL Table S1. The logistic regression model used to calculate the propensity score. Table S2. Distribution of propensity score among the treat and control groups of the full and matched

More information

Selective Serotonin Reuptake Inhibitors in Patients with Depression and Coronary Heart Disease: a meta-analysis.

Selective Serotonin Reuptake Inhibitors in Patients with Depression and Coronary Heart Disease: a meta-analysis. Selective Serotonin Reuptake Inhibitors in Patients with Depression and Coronary Heart Disease: a meta-analysis. Carmine Pizzi, MD 1, Anne Wilhelmina Saskia Rutjes, PhD 2,3 Grazia Maria Costa, MD 4, Fiorella

More information

Statins and Risk for Diabetes Mellitus. Background

Statins and Risk for Diabetes Mellitus. Background Statins and Risk for Diabetes Mellitus Kevin C. Maki, PhD, FNLA Midwest Center for Metabolic & Cardiovascular Research and DePaul University, Chicago, IL 1 Background In 2012 the US Food and Drug Administration

More information

STUDY DESIGN. Gregory W. Heath, D.H.Sc., M.P.H. Department of Medicine. Adapted from Jack M. Guralnik, M.D., PhD NIA/NIH, 2004.

STUDY DESIGN. Gregory W. Heath, D.H.Sc., M.P.H. Department of Medicine. Adapted from Jack M. Guralnik, M.D., PhD NIA/NIH, 2004. CLINICAL RESEARCH METHODS AND STUDY DESIGN Gregory W. Heath, D.H.Sc., M.P.H. Department of Medicine University of Tennessee College of Medicine, Chattanooga Adapted from Jack M. Guralnik, M.D., PhD NIA/NIH,

More information

Direct and Indirect Measures of Treatment Effects Including Surrogate Endpoints

Direct and Indirect Measures of Treatment Effects Including Surrogate Endpoints Direct and Indirect Measures of Treatment Effects Including Surrogate Endpoints John H Powers, MD SAIC in support of Division of Clinical Research, NIH Associate Clinical Professor of Medicine George Washington

More information

Supplementing Claims Data with Outpatient Lab Test Results to Improve Confounding Control

Supplementing Claims Data with Outpatient Lab Test Results to Improve Confounding Control Supplementing Claims Data with Outpatient Lab Test Results to Improve Confounding Control Sebastian Schneeweiss, MD, ScD Professor of Medicine and Epidemiology Division of Pharmacoepidemiology and Pharmacoeconomics,

More information

Extrinsic allergic alveolitis: incidence and mortality in the general population

Extrinsic allergic alveolitis: incidence and mortality in the general population Q J Med 2007; 100:233 237 doi:10.1093/qjmed/hcm008 Extrinsic allergic alveolitis: incidence and mortality in the general population M. SOLAYMANI-DODARAN 1, J. WEST 1, C. SMITH 2 and R. HUBBARD 2 From the

More information

Professional Certificate in Primary Care Psychology

Professional Certificate in Primary Care Psychology Professional Certificate in Primary Care Psychology The NAPPP Primary Care Psychology Certificate training program requires the completion of 10 courses. Each course awards 15 CE credit hours. NAPPP is

More information

Cigarette Smoking and Lung Cancer

Cigarette Smoking and Lung Cancer Centers for Disease Control and Prevention Case Studies in Applied Epidemiology No. 731-611 Cigarette Smoking and Lung Cancer Student's Guide Learning Objectives After completing this case study, the participant

More information

FULL COVERAGE FOR PREVENTIVE MEDICATIONS AFTER MYOCARDIAL INFARCTION IMPACT ON RACIAL AND ETHNIC DISPARITIES

FULL COVERAGE FOR PREVENTIVE MEDICATIONS AFTER MYOCARDIAL INFARCTION IMPACT ON RACIAL AND ETHNIC DISPARITIES FULL COVERAGE FOR PREVENTIVE MEDICATIONS AFTER MYOCARDIAL INFARCTION IMPACT ON RACIAL AND ETHNIC DISPARITIES Niteesh K. Choudhry, MD, PhD Harvard Medical School Division of Pharmacoepidemiology and Pharmacoeconomics

More information

Mental Health in the Quality Outcomes Framework

Mental Health in the Quality Outcomes Framework Mental Health in the Quality Outcomes Framework Tony Kendrick Professor of Primary Care, University of Southampton Rationale for QOF SMI indicators Mortality rates for people with SMI (schizophrenia,

More information

Diabetes Prevention in Latinos

Diabetes Prevention in Latinos Diabetes Prevention in Latinos Matthew O Brien, MD, MSc Assistant Professor of Medicine and Public Health Northwestern Feinberg School of Medicine Institute for Public Health and Medicine October 17, 2013

More information

Office ID Location: City State Date / / PRIMARY CARE SURVEY

Office ID Location: City State Date / / PRIMARY CARE SURVEY A. Organizational Characteristics PRIMARY CARE SURVEY We want to learn more about the general features of your office. A1. What health-related services does your office provide (check all that apply)?

More information

ESCMID Online Lecture Library. by author

ESCMID Online Lecture Library. by author Do statins improve outcomes of patients with sepsis and pneumonia? Jordi Carratalà Department of Infectious Diseases Statins for sepsis & community-acquired pneumonia Sepsis and CAP are major healthcare

More information

Cancer research in the Midland Region the prostate and bowel cancer projects

Cancer research in the Midland Region the prostate and bowel cancer projects Cancer research in the Midland Region the prostate and bowel cancer projects Ross Lawrenson Waikato Clinical School University of Auckland MoH/HRC Cancer Research agenda Lung cancer Palliative care Prostate

More information

ESC/EASD Pocket Guidelines Diabetes, pre-diabetes and cardiovascular disease

ESC/EASD Pocket Guidelines Diabetes, pre-diabetes and cardiovascular disease Diabetes, prediabetes and cardiovascular disease Classes of recommendations Levels of evidence Recommended treatment targets for patients with diabetes and CAD Definition, classification and screening

More information

What is meant by "randomization"? (Select the one best answer.)

What is meant by randomization? (Select the one best answer.) Preview: Post-class quiz 5 - Clinical Trials Question 1 What is meant by "randomization"? (Select the one best answer.) Question 2 A. Selection of subjects at random. B. Randomization is a method of allocating

More information

Managing depression after stroke. Presented by Maree Hackett

Managing depression after stroke. Presented by Maree Hackett Managing depression after stroke Presented by Maree Hackett After stroke Physical changes We can see these Depression Emotionalism Anxiety Confusion Communication problems What is depression? Category

More information

THE NEW ZEALAND MEDICAL JOURNAL

THE NEW ZEALAND MEDICAL JOURNAL THE NEW ZEALAND MEDICAL JOURNAL Vol 117 No 1206 ISSN 1175 8716 Changes in the use of Hormone Replacement Therapy in New Zealand following the publication of the Women s Health Initiative Trial Irma Bilgrami,

More information

Drugs for MS.Drug fact box cannabis extract (Sativex) Version 1.0 Author

Drugs for MS.Drug fact box cannabis extract (Sativex) Version 1.0 Author Version History Policy Title Drugs for MS.Drug fact box cannabis extract (Sativex) Version 1.0 Author West Midlands Commissioning Support Unit Publication Date Jan 2013 Review Date Supersedes/New (Further

More information

Hospital and Post Hospital Care for STEMI: Hospital to Home

Hospital and Post Hospital Care for STEMI: Hospital to Home Hospital and Post Hospital Care for STEMI: Hospital to Home John P. Erwin, III, MD, FACC Associate Professor of Medicine Texas A&M College of Medicine Co-Director, Cardiovascular Fellowship Program Hospital

More information

The Women s Health Initiative: The Role of Hormonal Therapy in Disease Prevention

The Women s Health Initiative: The Role of Hormonal Therapy in Disease Prevention The Women s Health Initiative: The Role of Hormonal Therapy in Disease Prevention Robert B. Wallace, MD, MSc Departments of Epidemiology and Internal Medicine University of Iowa College of Public Health

More information