Drivers of the Sex Disparity in Statin Therapy in Patients with Coronary Artery Disease: A Cohort Study

Abstract

Background: Women are less likely to be prescribed statins than men. Existing reports explain only a fraction of this difference. We conducted a study to identify factors that account for sex differences in statin therapy among patients with coronary artery disease (CAD). Methods and Results: We retrospectively studied 24,338 patients with CAD who were followed for at least a year between 2000 and 2011 at two academic medical centers. Women (9,006 / 37% of study patients) were less likely to either have initiated statin therapy (81.9% women vs. 87.7% men) or to have persistent statin therapy at the end of follow-up (67.0% women vs. 71.4% men). Women were older (72.9 vs. 68.4 years), less likely to have ever smoked (49.8% vs. 65.6%), less likely to have been evaluated by a cardiologist (57.5% vs. 64.5%) and more likely to have reported an adverse reaction to a statin (27.1% vs. 21.7%) (p < 0.0001 for all). In multivariable analysis, patients with history of smoking (OR 1.094; p 0.017), younger age (OR 1.013 / year), cardiologist evaluation (OR 1.337) and no reported adverse reactions to statins (OR 1.410) were more likely (p < 0.0001 for all) to have persistent statin therapy. Together, these four factors accounted for 90.4% of the sex disparity in persistent statin therapy. Conclusions: Several specific factors appear to underlie divergent statin therapy in women vs. men. Identifying such drivers may facilitate programmatic interventions and stimulate further research to overcome sex differences in applying proven interventions for cardiovascular risk reduction.