What Isn't a Case-Control Study?

BACKGROUND: Confusion exists among neurosurgeons when choosing and implementing an appropriate study design and statistical methods when conducting research. We noticed particular difficulty with mislabeled and inappropriate case-control studies in the neurosurgical literature. OBJECTIVE: To quantify and to rigorously review this issue for appropriateness in publication and to establish quality of the manuscripts using a rigorous technique. METHODS: Following a literature search, pairs drawn from 5 independent reviewers evaluated a complete sample of 125 manuscripts claiming to be case-control studies with respect to basic case-control criteria. Seventy-five papers were then subjected to a more rigorous appraisal for quality using the SIGN Methodology Checklist for case-control studies. RESULTS: Fifty publications were rejected based on basic criteria used to identify case-control design. Of the 75 subjected to quality analysis, 46 were felt to be acceptable for publication. Only 11 papers (9%) achieved the designation of high quality. Of the original 125 papers evaluated, 79 (63%) were inappropriately labeled case-control studies. CONCLUSION: Mislabeling and use of inappropriate study design are common in the neurosurgical literature. Manuscripts should be evaluated rigorously by reviewers and readers, and neurosurgical training programs should include instruction on choice of appropriate study design and critical appraisal of the literature.