The Magnitude and Potential Causes of Sex Disparities in Statin Therapy in Veterans with Type 2 Diabetes: A 10-year Nationwide Longitudinal Cohort Study

Background: Past research has shown that women eligible for statin therapy are less likely than their male counterparts to receive any statin therapy or be prescribed a statin at the guideline-recommended intensity. We compared statin treatment in men and women veterans from a national cohort of older veterans with type 2 diabetes. Methods: The Veterans Health Administration Corporate Data Warehouse and Centers for Medicare and Medicaid Services data were used to create a unique dataset and perform a longitudinal study of veterans with type 2 diabetes from 2007 to 2016. Mixed-effects logistic regression was used to model the association between the primary exposure (sex) and statin use. Results: The study included 714,212 veterans with diabetes, including 9,608 women, with an overall mean age of 75.9 years. In the unadjusted model for any statin use, women veterans had a 14% significantly lower odds of having any statin use compared with men. After adjusting for all covariates, including markers of Veterans Administration care use (service-connected disability rating, Veterans Administration use, and primary care visits) that serve as proxies for access and mental health comorbidities (depression and psychiatric disorder), this disparity narrowed from 14% to 3% and was no longer statistically significant. In the model for high-intensity statin therapy (high-intensity vs. low or none), women were 10% less likely than men to use high-intensity statins in the base model that included only time and sex. After adjusting for all measured covariates, the direction of the association changed and women had 16% higher odds of high-intensity statin use compared with men (odds ratio, 1.16; 95% confidence interval, 1.03-1.31). Conclusions: Consistent with prior research, in the unadjusted analysis a significant sex disparity was observed in statin use, with lower rates observed in women. For the outcome of any statin use, after adjustment for covariates that included variables that are proxies for access as well as psychiatric and depression comorbidities, this disparity lost statistical significance and narrowed. In the high-intensity statin versus low or none model, the direction of the association changed after controlling for measured covariates and women had a 16% higher odds of high-intensity statin use compared with men. This study highlights a persistent health disparity in lipid-lowering therapy for women veterans. Additional research is needed to further elucidate the reasons for and develop interventions to mitigate this persistent sex disparity in cholesterol management for veterans with diabetes. Published by Elsevier Inc. on behalf of Jacobs Institute of Women's Health, George Washington University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).