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

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1 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 Dr Tam Nguyen 14-Feb-13 Introduction to Clinical Research Dr Harin Karunajeewa 28-Feb-13 Evaluating the literature A/Professor Kerrie Sanders 14-Mar-13 Writing a research proposal Dr Lizzie Skinner 28-Mar-13 Beginners statistics: Study Design Professor Danny Liew 11-Apr-13 Referencing and EndNote Dr Tam Nguyen & Lynn Higgins 24-Apr-13 Mixed Methods: Quantitative & Qualitative Professor Terrence McCann 9-May-13 Using Excel for research Dr Lizzie Skinner 23-May-13 Making sense of your results Professor Danny Liew 6-Jun-13 Getting your work published A/Professor Kerrie Sanders 20-Jun-13 Writing Abstract for Research Week/ Conferences Dr Debra Kerr 4-Jul-13 Introduction to Study Designs and Biostatistics Danny Liew 1

2 Overview overview of study designs observational studies clinical trials basic biostatistics Classification of Study Designs observational [case series, case reports] ecological cross-sectional descriptive case-control cohort interventional clinical trials analytical 2

3 Classification of Study Designs observational [case series, case reports] ecological cross-sectional case-control nonlongitudinal cohort interventional clinical trials longitudinal Ecological Studies 3

4 CANCER Disease incidence 4/12/2013 Ecological Studies study of data at population/group level - no data on individuals easily and opportunistically undertaken, often using routinely collected data hypothesis-generating studies Ecological Study - Hypothetical Example plots of individual countries SMOKING Average smoking (cig/week) 4

5 Cross-Sectional Studies Cross-Sectional Studies sample of population selected and information obtained at one point/period in time large studies can take place over years, but each subject contributes data only once that is, there is no follow-up of subjects 5

6 Cross-Sectional Studies data collected via: questionnaires ± examinations ± investigations mostly descriptive outputs, especially prevalence eg, of CHD among Australians Example of Cross-Sectional Study 6

7 Case Control Studies Case Control Studies comparison of previous exposure status between: subjects with outcome of interest (cases) subjects without outcome of interest (controls) controls are often matched with cases, 1:1 or n:1 matching by confounders - eg: age, sex 7

8 Case Control Studies time exposure outcome step 1: define and recruit cases; recruit controls by matching to cases (outcome ascertainment 1st) step 2: determine previous exposure among subjects Case Control Studies explicit knowledge about temporal relationship between exposure and outcome useful for studying rare outcomes key output: odds ratio, approximation of relative risk of outcome conferred by exposure 8

9 Hypothetical Example Controls: no Kafoop s Syndrome Cases: Kafoop s Syndrome No smoking Smoking OR = (200*150) / (100*150) = 2.0 Interpretation: smoking doubles likelihood of Kafoop s Syndrome Kafoop s Syndrome 9

10 10

11 Cohort Studies Cohort Studies longitudinal, with follow-up of subjects collect incidence data comparison of outcomes between/among subgroups eg, not exposed vs exposed to risk factor derive relative risks (recall examples from British Doctor s Study) 11

12 Prospective Cohort Study time exposure outcome Key: explicit knowledge about the temporal relationship between exposure and outcome. Retrospective Cohort Study time exposure outcome Key: explicit knowledge about the temporal relationship between exposure and outcome. 12

13 Cohort Studies explicit (often-detailed) knowledge about temporal relationship between exposure and outcome can include multiple exposures and outcomes research hypotheses can be addressed post hoc in established cohorts The Framingham Heart Study 13

14 Framingham Risk Equation Clinical Trials 14

15 Clinically Proven Is it all a male conspiracy? The Age 11 July

16 Clinical Trials longitudinal studies designed to assess if an intervention (removal of exposure) changes the incidence of an outcome most interventions are expected to decrease the incidence of the outcome most involve a control group for comparison Clinical Trials intervention A assign intervention placebo / intervention B prospective follow-up to capture outcomes 16

17 Clinical Trials gold standard for evidence of causality active change of exposure status tightly controlled study environment provides most of the evidence for EBP 17

18 Key Outcomes relative measures of intervention effect: relative risks hazard ratios absolute measures of intervention effect: absolute risk/rate reduction number needed to treat survival analysis Randomisation random allocation of subjects into each arm of a clinical trial objective: treatment groups identical in all aspects other than the intervention rationale: reduce confounding 18

19 Confounding exposure outcome confounder Confounding in Clinical Trials intervention outcome confounder (age/sex etc...) 19

20 JAMA 2002; 288:

21 Basic Biostatistics Studies and Samples studies are undertaken on samples of the population of interest (cf census) studies are used to make inferences about the population of interest biostatistics is concerned with the extent to which study (sample) results reflect the truth 21

22 p value probability of the study result if it is assumed that the null hypothesis applies - truly no difference between the groups being compared ie, probability that the study result was a chance finding p value = conventional cut-off = 0.05 p < 0.05: statistically significant p 0.05: not statistically significant p = 0.02 p = 0.01 JAMA 2002; 288:

23 95% Confidence Interval interval within which there is 95% confidence that the true value lies if the null value is excluded, result is stat significant null value: value if the null hypothesis applies null value: 1.0 for ratios (eg HR, RR, OR) and 0 for differences (eg absolute risk differences) JAMA 2002; 288:

24 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 Dr Tam Nguyen 14-Feb-13 Introduction to Clinical Research Dr Harin Karunajeewa 28-Feb-13 Evaluating the literature A/Professor Kerrie Sanders 14-Mar-13 Writing a research proposal Dr Lizzie Skinner 28-Mar-13 Beginners statistics: Study Design Professor Danny Liew 11-Apr-13 Referencing and EndNote Dr Tam Nguyen & Lynn Higgins 24-Apr-13 Mixed Methods: Quantitative & Qualitative Professor Terrence McCann 9-May-13 Using Excel for research Dr Lizzie Skinner 23-May-13 Making sense of your results Professor Danny Liew 6-Jun-13 Getting your work published A/Professor Kerrie Sanders 20-Jun-13 Writing Abstract for Research Week/ Conferences Dr Debra Kerr 4-Jul-13 24