Healthy Skepticism Library item: 5560

Warning: This library includes all items relevant to health product marketing that we are aware of regardless of quality. Often we do not agree with all or part of the contents.

Publication type: Journal Article

Glynn RJ, Schneeweiss S, Wang PS, Levin R, Avorn J.
Selective prescribing led to overestimation of the benefits of lipid-lowering drugs.
J Clin Epidemiol 2006 Aug 01; 59:(8):819-28
http://linkinghub.elsevier.com/retrieve/pii/S0895-4356(06)00047-3

Abstract:

OBJECTIVE: Observational studies have found beneficial effects of lipid-lowering drugs on diverse outcomes, including venous thromboembolism, hip fracture, dementia, and all-cause mortality. Selective use of these drugs in frail people may confound these relationships. STUDY DESIGN AND SETTING: We measured 1-year mortality in two cohorts of New Jersey residents, aged 65-99 years, enrolled in state-sponsored drug benefits programs: 112,463 persons hospitalized during the years 1991-1994 and 106,838 nonhospitalized enrollees. Use of lipid-lowering drugs and other medications, as well as diagnoses, were evaluated before follow-up. RESULTS: In age- and sex-adjusted analyses, users of lipid-lowering drugs had a 43% reduced death rate relative to nonusers among hospitalized enrollees and a 56% reduction in the nonhospitalized sample. Available markers of frailty and comorbidity predicted decreased use of these drugs. Control for the propensity to use lipid-lowering drugs attenuated but did not eliminate these effects. After such adjustment, users had a 30% reduction in death rate (95% confidence interval [CI]: 25%-35%) among hospitalized enrollees and a 41% reduction (95% CI: 35%-47%) in the nonhospitalized sample. Unmeasured frailty associated with a 26%-33% reduced odds of receiving lipid-lowering therapy could explain this effect. CONCLUSION: Frailty and comorbidity that influence use of preventive therapies can substantially confound apparent benefits of lipid-lowering drugs on outcomes.