How Manipulated Clinical Evidence Could Distort Guidelines - the Case of Statins for Primary Prevention

This study excluded many patient for whom the statins were not contraindicated or warned against: uncontrolled hypertension; type 1 or type 2 diabetes mellitus on insulin or with a HgBA1C at least 10%; and body weight more than 50% "desirable limit for height."  (Based on the official contraindications and warnings for commonly used statins, e.g., see contraindications for Lipitor here, active liver disease, pregnancy for likely to become pregnant, nursing mothers, hypersensitivity to the medicine; and warnings: use of cyclosprine or strong CYP3A4 inhibitors, uncontrolled hypothyroidism, renal impairment.)  Thus the results may not generalize to many patients who would otherwise be considered statin candidates.  By excluding such patients, the results may bias the study towards minimizing the probabilities of harms that might occur were statins used on a wide population for primary prevention.Unknown Randomization and Allocation Concealment Procedures - According to the Cochrane Review, the study report did not explain how randomization or allocation concealment were accomplished.   Early Termination/ Multiple Comparisons - The study was terminated early based on an early look at the number of outcome events.  Two such early or interim analyses were planned.  Taking multiple looks at the data over time raises a multiple comparisons problem, and may lead to exaggerating the benefits of the treatment.(8). Furthermore, stopping early decreases the s...
Source: Health Care Renewal - Category: Health Medicine and Bioethics Commentators Tags: American College of Cardiology American Heart Association clinical trials conflicts of interest evidence-based medicine guidelines manipulating clinical research review articles Source Type: blogs