Variations in risk-adjusted cesarean delivery rates according to race and health insurance

OBJECTIVE. To assess the association between race and insurance and Cesarean delivery rates after adjusting for clinical risk factors that increase the likelihood of cesarean delivery. DESIGN. Retrospective cohort study in 21 hospitals in northeast Ohio. SUBJECTS. 25,697 women without prior cesarean deliveries admitted for labor and delivery January 1993 through June 1995. METHODS. Demographic and clinical data were abstracted from patients' medical records. The risk of cesarean delivery was adjusted for 39 maternal and neonatal risk factors that were included in a previously developed risk-adjustment model using nested logistic regression analysis. MAIN OUTCOME MEASURES. Odds ratios for cesarean delivery in nonwhite patients relative to whites and for patients with government insurance or who were uninsured relative to patients with commercial insurance. RESULTS. The overall rate of cesarean delivery was similar in white and nonwhite patients (15.8% and 16.1%, respectively), but rates varied (P < 0.001) according to insurance (17.0%, 14.2%, 10.7% in patients with commercial insurance, government insurance, and without insurance, respectively). However, after adjusting for clinical factors, the adjusted odds ratio (OR) of cesarean delivery was higher in nonwhite patients (OR = 1.34; 95% CI: 1.14-1.57; P < 0.001), but similar for patients with government insurance (OR = 1.01; 95% CI: 0.90-1.14; P = 0.84) and lower for uninsured patients (OR = 0.65; 95% CI, 0.41, 1.03; P = 0.067), albeit not statistically significant. In analyses stratified according to quintiles of predicted risk of cesarean delivery, racial differences were largely limited to patients in the lower risk quintiles. However, differences in odds ratios for uninsured patients were seen across the risk quintiles, although odds ratios were not statistically significant. CONCLUSION. After adjusting for clinical factors, race and insurance status may independently influence the use of cesarean delivery. The higher rates in nonwhites and lower rates in the uninsured may reflect differences in patient preferences or expectations, differences in physician practice, or unmeasured risk factors. The lower adds of cesarean delivery in uninsured women, particularly women at high risk, may raise the issue of underutilization of services and warrants further study.