When Are Statins Cost-Effective in Cardiovascular Prevention? A Systematic Review of Sponsorship Bias and Conclusions in Economic Evaluations of Statins

BACKGROUND: We examined sponsorship of published cost-effectiveness analyses of statin use for cardiovascular (CV) prevention, and determined whether the funding source is associated with study conclusions. METHODS AND FINDINGS: We searched PubMed/MEDLINE (up to June 2011) to identify cost-effectiveness analyses of statin use for CV prevention reporting outcomes as incremental costs per quality-adjusted life years (QALY) and/or life years gained (LYG). We examined relationships between the funding source and the study conclusions by means of tests of differences between proportions. Seventy-five studies were included. Forty-eight studies (64. 0%) were industry-sponsored. Fifty-two (69. 3%) articles compared statins versus non-active alternatives. Secondary CV prevention represented 42. 7% of articles, followed by primary CV prevention (38. 7%) and both (18. 7%). Overall, industry-sponsored studies were much less likely to report unfavourable or neutral conclusions (0% versus 37. 1%; p<0. 001). For primary CV prevention, the proportion with unfavourable or neutral conclusions was 0% for industry-sponsored studies versus 57. 9% for non-sponsored studies (p<0. 001). Conversely, no statistically significant differences were identified for studies evaluating secondary CV prevention (0% versus 12. 5%; p=0. 222). Incremental costs per QALY/LYG estimates reported in industry-sponsored studies were generally more likely to fall below a hypothetical willingness-to-pay threshold of US 50, 000. CONCLUSIONS: Our systematic analysis suggests that pharmaceutical industry sponsored economic evaluations of statins have generally favored the cost-effectiveness profile of their products particularly in primary CV prevention.