Abstract 21: Post-Coronary Revascularization Mortality in Diabetes Patients With and Without End-Stage Renal Disease: Do Outcome Disparities Exist?

Abstract

Background: Previously conducted studies have demonstrated that diabetes mellitus (DM) and end-stage renal disease (ESRD) can worsen survival prognosis in coronary artery disease (CAD) patients. It remains unclear whether racial and socio-economic disparities can affect the outcomes of coronary revascularization procedures in CAD patients with DM (CAD-DM), in particular in relation to the presence of ESRD. Study Objective: To investigate racial and socio-economic disparities in the in-hospital mortality outcomes of coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in CAD-DM patients with and without ESRD. Methods: We conducted a retrospective cohort study of in-hospital mortality in 353,711 CAD-DM patients [mean±SD age: 66.1±11.1 years; 65.2% (230,617 of 353,711) males] after CABG and PCI during 2007-2011. Median household income state quartile was used as a measure of patients’ socio-economic status (SES). Race was defined as white, black, Asian, or Native American. In-hospital patient death was a dichotomous outcome of interest. Adjusted odds ratios were obtained from multivariable logistic regression, adjusted for the type of coronary revascularization procedure and known clinical, demographic, and socio-economic covariates. Results: In the covariate-adjusted multivariable logistic regression analysis, post-procedure mortality in CAD-DM patients with ESRD was significantly higher than in their counterparts without ESRD (adjusted OR = 1.70, 95% CI: 1.56-1.87, p<0.001). Post-procedure mortality was independently associated not only with the type of procedure (PCI vs CABG, adjusted OR = 0.69, 95% CI: 0.65-0.73, p<0.001), age (3.7% increase for each year, 95% CI: 3.4-3.9%, p<0.001) and comorbidities status (12.5% increase for each point increase of the modified Elixhauser-Walraven score, 95% CI: 12.1-12.9%, p<0.001), but with race and SES too. Patients of the lowest household income quartile were more likely to die than the ones of the highest income quartile (adjusted OR = 1.14, 95% CI: 1.06-1.24, p=0.003). Blacks were more likely to undergo an emergency admission (44.9%) than Asians (38.3%), whites (37.0%) or Native Americans (34.0%; p<0.01 with multiple comparisons correction), and emergency admission was an independent predictor of post-procedure mortality (adjusted OR = 2.02, 95% CI: 1.90-2.13, p<0.001). C-statistic for the multivariable logistic regression model was 0.788. Conclusions: Results suggest existence of SES and racial disparities in in-hospital post-coronary revascularization mortality in CAD-DM patients independently of the type of procedure, presence of ESRD, comorbidities and demographic covariates. Further studies investigating the responsible mechanisms for these outcome disparities – possibly, disparities in the realized access to primary care – are warranted.