This document includes these contents: Appraising articles on harm/etiology, cohort study, case control study, randomized controlled trial, clinical scenario, clinical resolution,.Invite you to result. | Appraising Articles on Harm/Etiology Cohort Study A cohort study is an analytical study in which individuals with differing exposures to a suspected factor are identified and then observed for the occurrence of certain health effects over some period, commonly years rather than weeks or months. The occurrence rates of the disease of interest are measured and related to estimated exposure levels. Cohort studies can either be performed prospectively or retrospectively from historical records. Cohort Study Patients who have developed a disorder are identified and their exposure to suspected causative factors is compared with that of controls who do not have the disorder. This permits estimation of odds ratios (but not of absolute risks). The advantages of case-control studies are that they are quick, cheap, and are the only way of studying very rare disorders or those with a long time lag between exposure and outcome. Disadvantages include the reliance on records to determine exposure, difficulty in selecting control groups, and difficulty in eliminating confounding variables. Case Control Study A case-control study is an observational, retrospective study which "involves identifying patients who have the outcome of interest (cases) and control patients without the same outcome, and looking back to see if they had the exposure of interest." Case Control Study Patients with and without the exposure of interest are identified and followed over time to see if they develop the outcome of interest, allowing comparison of risk. Cohort studies are cheaper and simpler than RCTs, can be more rigorous than case-control studies in eligibility and assessment, can establish the timing and sequence of events, and are ethically safe. However, they cannot exclude unknown confounders, blinding is difficult, and identifying a matched control group may also be difficult. Case Control - Retrospective Retrospective case-control studies rely on people’s memories, making | Appraising Articles on Harm/Etiology Cohort Study A cohort study is an analytical study in which individuals with differing exposures to a suspected factor are identified and then observed for the occurrence of certain health effects over some period, commonly years rather than weeks or months. The occurrence rates of the disease of interest are measured and related to estimated exposure levels. Cohort studies can either be performed prospectively or retrospectively from historical records. Cohort Study Patients who have developed a disorder are identified and their exposure to suspected causative factors is compared with that of controls who do not have the disorder. This permits estimation of odds ratios (but not of absolute risks). The advantages of case-control studies are that they are quick, cheap, and are the only way of studying very rare disorders or those with a long time lag between exposure and outcome. Disadvantages include the reliance on records to determine
