Descriptive Studies 2019 PDF

DESCRIPTIVE STUDIES BISOLA ADEBAYO DEPARTMENT OF COMMUNITY HEALTH & PHC LASUCOM Why Conduct Studies To determine the burden of diseases or prevalence of risk factors, health behaviour or other characteristics that influence disease risk To the determine cause or risk factors for illness...

DESCRIPTIVE STUDIES BISOLA ADEBAYO DEPARTMENT OF COMMUNITY HEALTH & PHC LASUCOM Why Conduct Studies To determine the burden of diseases or prevalence of risk factors, health behaviour or other characteristics that influence disease risk To the determine cause or risk factors for illness To determine relative effectiveness of interventions Descriptive Studies Characterize who, where, or when in relation to what (outcome) Person: characteristics (age, sex, occupation) of the individuals affected by the outcome Place: geography (residence, work, hospital) of the affected individuals Time: when events (diagnosis, reporting; testing) occurred Purpose of Descriptive Studies To answer what, who, To generate where and hypothesis when Application of Descriptive Studies Knowledge of populations or subgroups most or least affected by a disease Efficient allocation of resources First step in search for determinants or risk factors that can be altered or eliminated to reduce or prevent disease Source of Data for Descriptive Studies Clinical Vital Census records Statistics data from health records facilities Employmen National Other t health data from surveys examinatio surveys done ns  Advantages of Descriptive Studies Generally less Less time- expensive consuming  Precludes the ability to test Limitations epidemiologic hypotheses  Aggregate Individual Ecological Studies Case Report Case Series Cross-sectional Study Types of Descriptive Studies  Also known as Ecological Studies Carried at population level, unit of analysis is the group Correlational Measure of association is the correlation coefficient, denoted by Studies ‘r’ Data represent average exposure levels rather than actual individual values Can be descriptive or analytical  Types Ecologic Ecologic trend comparison studies studies Advantages QUICK COMPARISON OF CHEAP DIFFERENT REGIONS/SUB-GROUPS  An ecological fallacy or bias results if inappropriate conclusions are drawn based on ecological data Characteristics ascribed to a group which the individual does not possess Disadvantage The bias occurs because an association observed between variables at the group/aggregate level does not necessarily represent the association that exists at the individual level Socio-economic confounding Case Reports and Case Series Case reports and case series are a type of descriptive study based on singular or grouped uncontrolled observations of patients or case-patients Case reports refer to singular reports on one individual patient, while case series are collections Empirical inquiries or investigations of a patient or a group of patients in a natural, real-world clinical setting Case reports and case series usually contain demographic information about the patient(s), for example, age, gender, ethnic origin.  Formal summary of a unique patient and his or her illness, including the presenting signs and symptoms, diagnostic studies, treatment course and outcome” Case Detailed report of the diagnosis, treatment, response to treatment, and follow-up after treatment of an Reports individual patient A case report consists of one or two cases, most often only one  Also known as case studies A case series is group of case reports involving patients who were Case given similar involve Case studies treatment multiple Series patients; they are a qualitative research method and include in- depth analyses or experiential inquiries of a person or group in their real-world setting. The case series or case series report usually consists of three to ten cases Advantages AFFORDABLE SHORT TIME SPAN FORM OBSERVATION MORE FLEXIBLE STRUCTURE  No epidemiological quantities Causal inference not possible, cannot test for valid association Lack of generalizability Bias including recall bias, its subjective Limitation Overinterpretation/ misinterpretation Emphasis on the rare Confidentiality Often not repeatable seldom published by high-impact medical journals  Also known as a prevalence study Data on exposure and disease are obtained at the level of the individual Cross- sectional Both data collected simultaneously Studies Based on single examination of a cross section of population ‘at one point of time’ Result is projected to whole population. No temporality  Descriptive Types Analytical  Collects information on frequency and distribution on Health-related exposures Descriptive Cross- Outcomes sectional Studies Main epidemiological outcome is prevalence of that outcome Often include a mix of questions and measurements on current and past events  Undertaken to investigate association between exposure to a risk factor and the outcome of interest Analytical Cross- sectional Study More appropriate to collect exposure and outcome data at same time if exposure to risk factor is constant  Relatively easy Cheap Advantages Useful for chronic diseases Snapshot of a population  Difficult to assess reasons for associations shown in cross-sectional studies Cannot establish temporality No causality Limitations Limited usefulness in inferring aetiology Include prevalent not incident cases Tells about distribution of disease but no aetiology