Statin use and uterine fibroid risk in hyperlipidemia patients: a nested case-control study

BACKGROUND: Statins are 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors primarily used for treatment of hyperlipidemia. Recently, they have been shown to inhibit proliferation of uterine fibroid cells and inhibit tumor growth in fibroid animal models. OBJECTIVE: We sought to examine the association between statin use and the risk of uterine fibroids and fibroid-related symptoms in a nationally representative sample of commercially insured women diagnosed with hyperlipidemia. STUDY DESIGN: We performed a nested case-control study of > 190,000 women enrolled in one of the nation's largest commercial health insurance programs. From a cohort of women aged 18-65 years diagnosed with hyperlipidemia from January 2004 through March 2011, we identified 47,713 cases (women diagnosed with uterine fibroids) and 143,139 controls (women without uterine fibroids) matched at a 1: 3 ratio on event/index date (month and year) and age (+/- 1 year). We used conditional and unconditional logistic regression to calculate odds ratios and 95% confidence intervals for the risk of uterine fibroids and fibroid-related symptoms associated with prior use of statins. RESULTS: Exposure to statins within 2 years before the event/index date was associated with a decreased risk of uterine fibroids (odds ratio, 0.85; 95% confidence interval, 0.83-0.87). In a separate subanalysis restricted to cases, statin users had a lower likelihood of having menorrhagia (odds ratio, 0.88; 95% confidence interval, 0.84-0.91), anemia (odds ratio, 0.84; 95% confidence interval, 0.79-0.88), or pelvic pain (odds ratio, 0.85; 95% confidence interval, 0.81-0.91) and of undergoing myomectomy (odds ratio, 0.76; 95% confidence interval, 0.66-0.87) compared to nonusers. CONCLUSION: The use of statins was associated with a lower risk of uterine fibroids and fibroid-related symptoms. Further studies, including randomized controlled trials, may be warranted.