Andrew J. Epstein, MPP, PhD a Mark J. Schlesinger, PhD a Bradford H. Gray, PhD b a Yale University School of Public Health Division of Health Policy and Administration b Urban Institute Racial and Ethnic Differences in Use of High Volume Hospitals and Surgeons Funding from the Robert Wood Johnson Foundation

Background Hospital and surgeon volume have been associated with lower mortality rates Minority patients suffer worse access to a range of surgical procedures, and worse outcomes Do minority patients also suffer worse access to high quality medical care providers? If so, why?

Study Objective To measure racial and ethnic differences in the use of high volume hospitals and surgeons in the New York City area To decompose the influence of inter- and intra- hospital referral patterns on differences in high volume surgeon use

Project Scope This presentation focuses on results for carotid endarterectomy (CE), percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery We examine 7 other procedures with a volume- mortality association: –Abdominal aortic aneurysm repair –Surgery for pancreatic, breast, colorectal, gastric and lung cancers –Total hip replacement

Data New York hospital discharge data –All discharges for hospitals treating patients residing in New York City, Westchester and Nassau Counties –Contains demographic, diagnosis, procedure, payer, admission and discharge status data, and unique hospital and surgeon identifiers –Covers Surgeon volume calculated statewide and checked against discharge data during

Study Sample Patient inclusion criteria –CE: ICD-9-CM principal procedure code –PCI: procedure code 36.01, 36.02, or –CABG: procedure code – 18 years of age –Residential ZIP Code in New York City area –Non-missing surgeon identifier Sample size –CE: 4,638(276 Black, 63 Asian, 225 Latino) –PCI: 34,598(2,332 B, 668 A, 2,030 L) –CABG: 14,509(988 B, 332 A, 919 L)

Provider Volume Thresholds HospitalSurgeon CE50 a 30 a PCI400 b 138 a CABG450 b 150 a To be designated high volume, a provider had to perform at least the following number of procedures annually on average during a – Halm, Lee Chassin, Ann Int Med, 2002; b – Leapfrog Group, and Birkmeyer and Dimick, Surgery, 2004

Statistical Analysis Χ 2 tests and linear regression were used to determine association of race and high volume provider use Regressions adjusted for patient sex, age, admission type and source, insurance status and number of Elixhauser comorbidities Models alternatively included patient residence ZIP Code fixed effects and hospital fixed effects.

Crude Percent High Volume Provider Use by Race - CE p<0.0001

Crude Percent High Volume Provider Use by Race - PCI p<0.0001

Crude Percent High Volume Provider Use by Race - CABG p<0.0001

Adjusted Probability of High Volume Hospital Use by Race Baseline ModelCEPCICABG Black-0.315***-0.138***-0.190*** Asian ***-0.244*** Latino-0.182***0.017***-0.086*** Incl. Patient ZIP Code Fixed EffectsCEPCICABG Black-0.147***-0.105***-0.164*** Asian ***-0.168*** Latino-0.066*0.036***0.025 *** p<0.01, ** p<0.05, * p<0.10 Findings expressed as the absolute difference in the probability of treatment at a high volume hospital for minority patients compared with white patients. A negative number indicates a lower probability for minority patients.

Adjusted Probability of High Volume Surgeon Use by Race *** p<0.01, ** p<0.05, * p<0.10 Findings expressed as the absolute difference in the probability of treatment by a high volume surgeon for minority patients compared with white patients. A negative number indicates a lower probability for minority patients. Baseline ModelCEPCICABG Black-0.235***-0.161***-0.268*** Asian **-0.154*** Latino-0.172***-0.133***-0.232*** Incl. Patient ZIP Code & Hospital Fixed EffectsCEPCICABG Black *** Asian Latino-0.098* ***

Results Summary Minorities significantly (p<0.10) less likely to use high volume hospitals –Baseline models: 8-9 procedures –ZIP Code fixed effects: 5-8 procedures Minorities significantly (p<0.10) less likely to use high volume surgeons Baseline ZIP Code & modelsZIP Code FEsHospital FEs Blacks1052 Asians 643 Latinos 753

Limitations Data do not reveal patients true sets of provider choices We cannot rule out that referrals of patients to providers were based on other (i.e., non-volume) quality of care measures Data field indicating operating physician is not audited

Conclusion Minority patients in the New York City area were less likely to be treated by high volume providers Differences in the geographic distributions of patients and providers explain a large proportion of racial and ethnic differences in access However, minority patients from the same ZIP Codes were still less likely to be treated by high volume providers For a few procedures, minority patients from the same ZIP Codes treated at the same hospitals were less likely to be treated by high volume surgeons

Policy Significance Evidence that minority patients are steered to low volume surgeons within a hospital was found only for 3 of 10 procedures This suggests systematic racial discrimination is not the primary driver Instead, minority patients and their referring physicians appear to have both differing availability and preferences for providers than white patients Is it easier to improve the quality of care at these institutions than it would be to shift minority referral patterns toward higher quality institutions?