Physician specialty and carotid stenting among elderly medicare beneficiaries in the United States

Abstract

Background: The use of carotid stenting is rising across the United States. How physician specialty relates to its utilization rates or outcomes is uncertain.

Methods: We performed an observational analysis of fee-for-service Medicare beneficiaries 65 years or older undergoing carotid stenting between 2005 and 2007 in 306 hospital referral regions (HRRs). We first determined how frequently carotid stenting was performed by different specialists within each HRR and then used multivariable regression models to compare population-based utilization rates and 30-day outcomes for this procedure across HRRs based on the proportion performed by cardiologists, surgeons, radiologists, or a mix of specialists.

Results: In 272 HRRs where at least 15 procedures were performed during the study period, we identified 28 700 carotid stenting procedures performed by 2588 operators. While cardiologists made up approximately one-third of these operators, they were responsible for 14 919 (52.0%) procedures. Significant differences were noted in the characteristics of patients treated by cardiologists compared with other specialties, including higher rates of invasive cardiac procedures and lower rates of acute stroke or transient ischemic attacks in the 180 days prior to carotid stenting. Population-based utilization rates were significantly higher in HRRs where cardiologists performed most procedures relative to HRRs where most were done by other specialists or a mix of specialists (P < .001). In contrast, risk-standardized outcomes did not differ across HRRs based on physician specialty.

Conclusions: Carotid stenting is being performed by operators from diverse specialties. Hospital referral regions where cardiologists perform most procedures have higher population-based utilization rates with similar outcomes.

Figure 1

Cumulative number of procedures of carotid stenting over time by specialty.

Figure 2

Map of HRRs where cardiologists, surgeons and radiologists perform most carotid stenting.

Figure 3

Mean rate of carotid stenting per 10,000 enrollees in hospital referral regions (HRRs) based on the proportion performed by cardiologists. HRRs where cardiologists performed most carotid stenting had higher adjusted utilization rates than others(P<0.001).