Does Payer Status Impact Clinical Outcomes after Cardiac Surgery? A Propensity Analysis

Abstract

Medicaid patients bear proportionately greater financial responsibility for the cost of outpatient care and medication than non-Medicaid patients. We hypothesized that this difference in provision of continuing care would be associated with adverse clinical outcomes after cardiac surgery. In a retrospective cohort analysis, 5056 consecutive adult patients undergoing cardiac surgery at a single institution between 2005 and 2010 were divided according to payer status. Propensity scores were calculated using 16 preoperative and demographic variables for each patient, and 461 1:1 propensity score-matched pairs were analyzed. Patient socioeconomic position was determined using aggregate data derived from zip codes. The main outcome measures were early mortality, postoperative complications, and patient survival. In multivariate analysis, Medicaid was found to be an independent predictor of worse survival after cardiac surgery (hazard ratio [HR], 2.1; 95% confidence interval [CI], 1.2-3.7; P = .01). No significant difference was observed in operative mortality in the 2 groups. After propensity score matching and controlling for socioeconomic position, the only independent predictors of worse midterm survival were an ejection fraction = 30% (HR, 1.7; 95% CI, 1.1-2.7; P = .02) and a higher logistic EuroSCORE (HR, 1.03; 95% CI, 1.0-1.1; P = .02). Comorbidity and lower socioeconomic status appear to be more important predictors of late mortality after cardiac surgery than payer status, which does not have a significant impact on survival.