Context: Referral to high-volume hospitals has been recommended for operations with a demonstrated volume-outcome relationship. The characteristics of patients who receive care at low-volume hospitals may be different from those of patients who receive care at high-volume hospitals. These differences may limit their ability to access or receive care at a high-volume hospital.
Objective: To identify patient characteristics associated with the use of high-volume hospitals, using California's Office of Statewide Health Planning and Development patient discharge database.
Design, setting, and participants: Retrospective study of Californians receiving the following inpatient operations from 2000 through 2004: elective abdominal aortic aneurysm repair, coronary artery bypass grafting, carotid endarterectomy, esophageal cancer resection, hip fracture repair, lung cancer resection, cardiac valve replacement, coronary angioplasty, pancreatic cancer resection, and total knee replacement.
Main outcome measures: Patient race/ethnicity and insurance status in high-volume (highest 20% of patients by mean annual volume) and in low-volume (lowest 20%) hospitals.
Results: A total of 719,608 patients received 1 of the 10 operations. Overall, nonwhites, Medicaid patients, and uninsured patients were less likely to receive care at high-volume hospitals and more likely to receive care at low-volume hospitals when controlling for other patient-level characteristics. Blacks were significantly (P<.05) less likely than whites to receive care at high-volume hospitals for 6 of the 10 operations (relative risk [RR] range, 0.40-0.72), while Asians and Hispanics were significantly less likely to receive care at high-volume hospitals for 5 (RR range, 0.60-0.91) and 9 (RR range, 0.46-0.88), respectively. Medicaid patients were significantly less likely than Medicare patients to receive care at high-volume hospitals for 7 of the operations (RR range, 0.22-0.66), while uninsured patients were less likely to be treated at high-volume hospitals for 9 (RR range, 0.20-0.81).
Conclusions: There are substantial disparities in the characteristics of patients receiving care at high-volume hospitals. The interest in selective referral to high-volume hospitals should include explicit efforts to identify the patient and system factors required to reduce current inequities regarding their use.