Critical Appraisal of a research article Dr Vimal Karani Associate Professor in Nutrigenetics & Nutrigenomics Programme Director for UG Nutrition Degree programmes University of Reading, UK What is a critical appraisal? Critical appraisal is a systematic process used to identify the strengths and weaknesses of a research article in order to assess the usefulness and validity of research findings. Critical appraisal is an important element of evidence- based medicine What are the components of a critical appraisal? Two important components: 1. An evaluation of the appropriateness of the study design for the research question & 2. A careful assessment of the key methodological features of this design. Other factors to consider the suitability of the statistical methodologies used and their subsequent interpretation the relevance of the research to one's own practice. Things to remember Decide whether studies have been undertaken in a way that makes their findings reliable Make sense of the results Know what these results mean in the context of the decision they are making Different types of questions require different study designs Aetiology: what caused this illness? Diagnosis: what does this test result mean in this patient? Prognosis: what is likely to happen to this patient? Harm: is having been exposed to this substance likely to do harm, and, if so, what? Effectiveness: is this treatment likely to help patients with this illness? Qualitative: what are the outcomes that are most important to patients with this condition? Things to remember When reading any research (systematic review, RCT, economic evaluation or other study design), it is important to remember that there are three broad things to consider: Validity, Results, Relevance It is always necessary to consider the following questions: Has the research been conducted in such a way as to minimise bias? If so, what does the study show? What do the results mean for the particular patient or context in which a decision is being made? Assignment You will be provided with a research article You will have to identify the strengths and weaknesses of the article General epidemiology - principles Outcome: disease or continuous trait Exposure: continuous or categorical Design: observational (cohort, case-control), experimental (trials) Co-variables/confounders: e.g. age, gender, … Epidemiological studies Case-control Prospective Cohort Longitudinal cross-sectional Retrospective Cohort Longitudinal Randomised Trial now Concept time Exposed Unexposed disease Cohort studies – study population Selection of study population important to avoid bias Select on exposure vs non-exposure Select defined population Age-range suitable for follow-up often difficult to find representative sample due to selection bias onset of disease within 10 – 15 years Large sample size for rare diseases