A group of rheumatologists wants to study the association between past use of procainamide for the treatment of arrhythmias and drug-induced lupus. The rheumatologists plan to conduct a case-control study to evaluate the association. Which of the following corresponds with the proposed study design?
A)Controls without a history of procainamide use should be excluded from the study
B)Individuals with a history of procainamide use should be identified as cases, and individuals with no history of procainamide use should be identified as controls
C)Individuals with and without drug-induced lupus should be compared with respect to their frequency of prior procainamide use
D)The frequency of drug-induced lupus should be compared in individuals with and without a history of procainamide use at the beginning of the study
E)The study should begin by identifying individuals based on their history of procainamide use and end by comparing the incidence of drug-induced lupus in each group

Question

A group of rheumatologists wants to study the association between past use of procainamide for the treatment of arrhythmias and drug-induced lupus.  The rheumatologists plan to conduct a case-control study to evaluate the association.  Which of the following corresponds with the proposed study design?
A)Controls without a history of procainamide use should be excluded from the study
B)Individuals with a history of procainamide use should be identified as cases, and individuals with no history of procainamide use should be identified as controls
C)Individuals with and without drug-induced lupus should be compared with respect to their frequency of prior procainamide use
D)The frequency of drug-induced lupus should be compared in individuals with and without a history of procainamide use at the beginning of the study
E)The study should begin by identifying individuals based on their history of procainamide use and end by comparing the incidence of drug-induced lupus in each group

Quizplus · Accepted Answer

Explanation: 11ec2b69_c109_ad55_8f63_65234b91c917_MD0005_00 A case-control study is a type of analytical observational study design in which potential participants are initially identified as "cases" or "controls" according to an outcome status (ie, disease or condition of interest). In this question, individuals with drug-induced lupus are cases and individuals without drug-induced lupus are controls. Once identified, cases and controls are then assessed for past exposure to ≥1 risk factors of interest. The risk factor here is past use of procainamide for the treatment of arrhythmias. The frequency of exposure to the risk factor is measured and compared between cases and controls to estimate the association between the risk factor and outcomes of interest. In other words, the frequency of prior procainamide use (ie, risk factor) should be compared among patients with (ie, cases) and without (ie, controls) drug-induced lupus. (Choice A) Controls without a history of procainamide use represent a portion of the control group. Excluding these individuals results in a frequency of exposure to the risk factor (eg, history of procainamide use) of 100% in the control group, which is incorrect. (Choice B) A case-control study begins by identifying individuals based on outcome or disease status (eg, drug-induced lupus), not risk factor status (eg, history of procainamide use). (Choices D and E) A cohort study (not a case-control study) begins by identifying individuals as exposed or nonexposed to a risk factor (eg, history of procainamide use) and ends by comparing outcome rates (eg, drug-induced lupus incidence) between the exposed and nonexposed groups. Educational objective: A case-control study is an observational study design. It begins with individuals who have the outcome (ie, cases) and compares them with individuals who do not have the outcome (ie, controls) according to a history of exposure to ≥1 risk factors.

A Group of Rheumatologists Wants to Study the Association Between