Racial variations in the rates of carotid angiography and endarterectomy in patients with stroke and transient ischemic attack

Background: Carotid endarterectomy is emerging as the treatment of choice for patients with symptomatic carotid artery stenosis at low operative risk. We sought to determine if racial variations in the rate of carotid angiography and endarterectomy exist in the Veteran Affairs health care system among patients who are insulated from the cost of their care. Methods: From a national database of all hospitalizations at Veterans Affairs medical centers, we identified a cohort of patients with diagnoses of stroke or transient ischemic attack who were likely to be candidates for carotid angiography and endarterectomy. We used logistic regression to determine if the patient's race was associated with receiving carotid angiography and endarterectomy, after adjusting for patient's age, degree of eligibility for Veterans Affairs care, socioeconomic status, comorbidities associated with hospital admission, and geographic region of the hospital. Results: Of the 35 922 veterans in the cohort, 3535 (9.8%) underwent angiography during the study period and 1249 (3.5%) had carotid endarterectomy. Blacks constituted 18.2% of the patients with a history of stroke or transient ischemic attack, 9.8% of the patients having angiography, but only 4.2% of the patients undergoing carotid endarterectomy. Whites constituted 77.1% of the patients with a history of stroke or transient ischemic attack, 86.1% of the patients receiving angiography, and 93.0% of those having carotid endarterectomies. Alter adjusting for confounding variables, black patients continued to have a significantly lower likelihood than white patients of undergoing angiography (risk ratio=0.47; 95% confidence interval=0.42, 0.53) and subsequent endarterectomy (risk ratio=0.28; 95% confidence interval=0.20, 0.38). Conclusions: Socioeconomic status and access to care within a large managed health care system do not fully explain racial differences in the rate of carotid angiography and endarterectomy. Either referral bias for evaluation for carotid endarterectomy or racial differences in the extent and location of cerebrovascular disease are more important explanations for the observed racial variations.