Journal of clinical epidemiology
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Despite guidelines recommending the use of formal tests of interaction in subgroup analyses in clinical trials, inappropriate subgroup-specific analyses continue. Moreover, trials designed to detect overall treatment effects have limited power to detect treatment-subgroup interactions. This article quantifies the error rates associated with subgroup analyses. ⋯ Although it is generally recognized that subgroup analyses can produce spurious results, the extent of the problem may be underestimated.
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Comparative Study
24-item Roland-Morris Disability Questionnaire was preferred out of six functional status questionnaires for post-lumbar disc surgery.
Measurement properties of questionnaires should be based on samples of populations on whom these measurements will be used. The purpose of this study is to establish an evidence based recommendation regarding the use of functional status questionnaires in patients following a lumbar disc surgery by a direct comparison of the reproducibility and responsiveness. ⋯ The use of the RDQ-24 for this specific post-surgery population is suggested. The optimal cut-off point of the RDQ-24 that minimizes the overall classification error was found to be 3.5 with a sensitivity of 94.6% and a specificity of 88.2%.