Treatment differences by health insurance among outpatients with coronary artery disease: insights from the national cardiovascular data registry.

OBJECTIVES

This study examined the association between insurance status and physicians' adherence with providing evidence-based treatments for coronary artery disease (CAD).

METHODS

Within the PINNACLE (Practice Innovation and Clinical Excellence) registry of the NCDR (National Cardiovascular Data Registry), the authors identified 60,814 outpatients with CAD from 30 U.S. practices. Hierarchical modified Poisson regression models with practice site as a random effect were used to study the association between health insurance (no insurance, public, or private health insurance) and 5 CAD quality measures.

RESULTS

Of 60,814 patients, 5716 patients (9.4%) were uninsured and 11,962 patients (19.7%) had public insurance, whereas 43,136 (70.9%) were privately insured. After accounting for exclusions, uninsured patients with CAD were 9%, 12%, and 6% less likely to receive treatment with a beta-blocker, an angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker (ACE-I/ARB), and lipid-lowering therapy, respectively, than privately insured patients, and patients with public insurance were 9% less likely to be prescribed ACE-I/ARB therapy. Most differences by insurance status were attenuated after adjusting for the site providing care. For example, whereas uninsured patients with left ventricular dysfunction and CAD were less likely to receive ACE-I/ARB therapy (unadjusted RR: 0.88; 95% CI: 0.84 to 0.93), this difference was eliminated after adjustment for site (adjusted RR: 0.95; 95% CI: 0.88 to 1.03; p = 0.18).

CONCLUSIONS

Within this national outpatient cardiac registry, uninsured patients were less likely to receive evidence-based medications for CAD. These disparities were explained by the site providing care. Efforts to reduce treatment differences by insurance status among cardiac outpatients may additionally need to focus on improving the rates of evidence-based treatment at sites with high proportions of uninsured patients.