Introduction to Observational studies Dr. Javaria Gulzar Clinical Research Associate SCRC.

Transcription

1 Introduction to Observational studies Dr. Javaria Gulzar Clinical Research Associate SCRC.

2 Observational Study A study in which a researcher simply observes behavior in a systemic manner with out any active intervention.

3 Study designs Cross-sectional studies. Cohort studies. Case- control studies.

4 Cross- sectional studies To identify disease/ health related states at a particular point in time. Speech and verbal communication skills in children. Prevalence Aims.

5 Aims- cross-sectional study To identify disease or health related states and suspected determinants. To test hypothesis on disease causation by showing degree of co relation between possible determinants and disease. To assist health service planning by measuring the burden of disease in subgroups and identifying those in greater need of services.

6 Cohort Studies Group of persons who share a common experience. Followed over time to assess:- - Incidence of disease -Progression of disease

7 AOM -GSK Study Title : An observational, retrospective, multicountry, cohort study to evaluate the incidence of acute Otitis media in children aged 0-5 years in the Middle East and North African countries. Study duration : 05 Dec 2012 to 23 Dec Approved from IRB at Shifa. Target enrolment : 1000 subjects

8 AOM- OBJECTIVE To estimate incidence of clinical acute Otitis media in medical practice. To estimate proportion of subject with recurrent disease. To estimate proportion of subjects with treatment failures. To describe clinical management.

9 Study description

10 AOM. Data locked: 08 April Data collection : Remote data entry using electronic case report forms.

11 Case Control study Recruits cases with the disease and then find concurrent group of controls with out the disease and looks back through time to compare their exposure to see if any appear to relate to the development of the disease. Retrospective. Investigating rare diseases.

12 PARTICIPANTS: Inclusion criteria were parkinsonism (>or=2 cardinal signs), diagnosis within 8 years of recruitment (to minimize survival bias), and ability to Occupation and risk of parkinsonism-a case control Risk of parkinsonism in occupations (agriculture, study education, health care, welding, and mining) and toxicant exposures (solvents and pesticides) putatively associated with parkinsonism. OBJECTIVE: To investigate occupations, specific job tasks, or exposures and risk of parkinsonism and clinical subtypes. DESIG n:case-control

13 Case control study. Control subjects were primarily nonblood relatives or acquaintances of patients. Results : 519 cases and 511 controls Pesticides exposure was reported to have high rates of parkinsonism rather work type.

14 Impact of study design on bias and confounding Probability of Crosssectional Cohort Case-control Randomized control trial Selection bias medium low high low Observer bias medium low high Low[blinded trials ] Recall bias high low high low Confounding bias Loss to follow up medium low medium Very low nil high low medium Sample size large Very large medium large Economical Cheap and easy costly cheap Expensive

15 scenarios To investigate the association between the hepatitis B surface antigen(hbsag) and the development of primary hepatocellular carcinoma. The study was conducted among male government employees who were enrolled through routine health care services. All participants completed a health questionnaire and provided a blood sample at the time of their entry into the study. Participants were then followed up for an average of 3.3 years..type OF STUDY IS

16 CASE -1 COHORT STUDY

17 CASE-2 Demonstration of the link between tobacco smoking and lung cancer..

18 Case-2 CASE-CONTROL STUDY

19 CASE 03 How early do the speech and verbal skills develop in children..

20 Case-03 CROSS SECTIONAL STUDY

21 Case 04 Comparison of single dose oral Secnidazole with multiple doses of intravaginal Clindamycin for symptomatic Bacterial Vaginosis

22 Case-04 Randomized controlled trial.

23 THANK YOU