Statins have strong recommendations for secondary prevention of future cardiovascular events in patients with ischemic heart disease (IHD). However, statins remain vastly underused in patients with cardiovascular disease and those at high risk of cardiovascular disease. The identified factors contributing to health care disparities in vulnerable population include having a low income, older age, being residents of rural area, and residing in southeastern United States. Multiple analyses from various databases have reported that disparities in optimal use of statins are more prevalent among racial/ethnic minorities. , Despite adequate availability, statin use is affected by insurance coverage and out-of-pocket cost especially in low-income households. , Consequently, we sought to evaluate the utilization trends of statins among outpatient visits of adults with IHD within the Medicaid population in the United States from 2006 to 2015 using the National Ambulatory Medical Care Survey (NAMCS) database.
NAMCS is a national 2-stage sample survey of visits to non–federally employed office-based physicians in the United States, which is conducted by the National Center for Health Statistics in the Centers for Disease Control and Prevention. We conducted a retrospective analysis of adult (age 18 to 64 years) patient visits, with Medicaid insurance, to office-based physicians from NAMCS database between 2006 and 2015, which provided annual nationally representative samples of physician visits.
Patients with IHD were identified using an affirmative response to the question “Does the patient have ischemic heart disease?” in the patient record form. Descriptive statistics were used to analyze the visits in which statin use was reported. Multivariable logistic regression analysis was used to identify the predictors of statin use. Covariates included were age, gender, ethnicity, race, metropolitan statistical area, region, and calendar year (2006 to 2007, 2008 to 2009, 2010 to 2011, 2012 to 2013, 2014, and 2015). Overall prescribing trends were studied from 2006 to 2015.
Weighted sample of 5194688 visits (36.83%) reported use of statin in IHD with the mean patient age of 54.03 (0.57) years and men (45.25%). The study population included predominantly White participants (77.8%), whereas Black participants constituted 17.4%. The region-wise distribution of visits included South (38.55%), Northeast (24.79%), West (18.42), and finally, Midwest regions (18.24%). Most visits occurred in the metropolitan statistical area (88.21%). There was no significant trend seen in statin use from 2006 to 2007 (30.3%) to 2014 to 2015 (38%) (p = 0.64; Figure 1 ).
Multivariate analysis showed that the increased likelihood of statin use was associated with increasing age (adjusted odds ratio [aOR] 1.04, 95% confidence interval [CI] 1.01 to 1.07, p = 0.019) and the decreased likelihood of statin use was associated with South (aOR 0.43, 95% CI 0.19 to 0.96, p = 0.04) and West (aOR 0.36, 95% CI 0.14 to 0.90, p = 0.029) regions compared with the Northeast region. There was no difference in statin use when stratified by gender (men: aOR 1.54, 95% CI 0.82 to 2.89, p = 0.179), race (Black: aOR 0.98, 95% CI 0.40 to 2.40, p = 0.958), others (aOR 1.20, 95% CI 0.38 to 3.73, p = 0.758), and metropolitan area (nonmetropolitan statistical area: aOR 1.32, 95% CI 0.65 to 2.68, p = 0.443).
Our study showed that (1) statins were vastly underused in patients with Medicaid (cumulatively just one-third of the patient population), and (2) there were no significant disparities in statin use among various demographics within the Medicaid population.
A similar NAMCS 2004–based study reported lipid-lowering medicine use in 40.4% of patients with IHD in ambulatory medical visits. Despite strong guideline recommendations, statin use remained suboptimal in IHD over the next 10 years, as evidenced by our study. Previous studies have reported that lack of insurance and racial disparity pose a challenge in the uptake of statins for secondary prevention of IHD in vulnerable patient populations. , Moreover, there is also a racial disparity in screening for hyperlipidemia in Black and Hispanicminorities. Interestingly, our study revealed no significant racial disparities in the Medicaid population, which potentially emphasizes the importance of insurance in reducing the disparities in health care. Recent expansion of Medicaid with the Affordable Care Act has shown to increase the number of prescriptions of statins by 89.7% from 2011 to 2018. This may have potential long-term cardiovascular benefits among lower-income and uninsured patient populations.
Our study has some limitations. NAMCS does not provide details of medication adherence. However, statin underuse is less likely due to nonadherence. The generalizability of our results is limited due to being primarily based on patients with Medicaid. Moreover, there are no data available regarding contraindication or adverse effects of statins, which may have affected statin prescription.
In conclusion, to the best of our knowledge, our study is the first to report statin use in patients with Medicaid with IHD at a national level. Our results point toward the importance of access to affordable health care through insurance, which can help mitigate the disparities in medication use in vulnerable patient population. Strenuous efforts should be made to expand insurance access to optimize health care outcomes.
Ethical Approval
This study is exempted from institutional review board approval, as this is a publicly available deidentified data set.
Declaration of Competing Interest
The authors have no conflicts of interest to declare.
Acknowledgments
None.
References
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