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

<div><p>Background</p><p>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.</p> <p>Methods and Findings</p><p>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%; <i>p</i><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 (<i>p</i><0.001). Conversely, no statistically significant differences were identified for studies evaluating secondary CV prevention (0% versus 12.5%; <i>p</i>=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.</p> <p>Conclusions</p><p>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.</p> </div

Flow diagram of study selection

<p><b>process</b>.</p

Variations in cost-effectiveness results by funding source and prevention category: a) Primary CV prevention and b) Secondary CV prevention.

<div><p>CV: Cardiovascular.</p> <p>Note: Each dot represents an incremental cost (in US$) per QALY/LYG in the reviewed articles. The horizontal line represents the willingness-to-pay threshold.</p></div

Productivity and patterns of collaboration by 50 top countries.

<p>Productivity and patterns of collaboration by 50 top countries.</p

Most prolific journals and most commonly used keywords per journal subject category.

<p>Most prolific journals and most commonly used keywords per journal subject category.</p

Most productive authors.

<p>Most productive authors.</p

Co-words network of the author keywords.

<p>Node sizes are proportional to the number of papers and line thicknesses are proportional to the number of co-occurrences of words. Node colors: blue = words related to general terms; green = words related to diseases/disorders, signs and symptoms; yellow = interventions.</p

Productivity and patterns of collaboration by 50 top countries.

<p>Productivity and patterns of collaboration by 50 top countries.</p

Selection of papers.

<p>Flowchart.</p

Number of papers by year of publication.

<p>Note: Data for 2016 up to November 8^th.</p