Misclassification of study designs in the dermatology literature

The appropriate classification of study designs is important for review and assessment of the relevant scientific literature as a basis for decision making; however, little is known about whether study designs have been appropriately reported in the dermatology literature. We aimed to validate the study designs in the dermatology literature and investigate discrepancies between author-reported and actual study designs. We reviewed all issues of 3 major dermatology journals from January to December 2016. A total of 295 original articles investigating associations between exposures and health outcomes were included for analysis. We used a validated algorithm to classify the study designs. Among the 295 articles, 174 (59.0%) clearly mentioned the study design in the text. All interventional studies were correctly classified on the basis of study design (n = 42); however, 35 of 132 observational studies (26.5%) showed discrepancies between the author-reported and actual study design. When the author-reported design was a prospective cohort, retrospective cohort, or case-control study (n = 61), approximately half of the studies were misclassified by the authors (n = 30). We analyzed only 3 journals in the dermatology field. Our findings revealed substantial discrepancies between author-reported and actual study designs in the dermatologic literature, particularly among observational studies.