Prevalence and impact of non-cardiovascular comorbidities among older adults hospitalized for non-ST segment elevation acute coronary syndrome

Background: There is a paucity of information on the prognostic importance of non-cardiovascular comorbidities (NCCs) among patients with non-ST-elevation acute coronary syndrome (NSTE-ACS). This study examined the prevalence and impact of NCCs on the length of stay (LOS) and mortality among older adults hospitalized for NSTE-ACS. Methods: Among 1,488 older adults (mean age 79.4 +/- 8.4 years; 62.0% male) hospitalized for NSTE-ACS at a tertiary hospital in Melbourne, Australia, during 2013-2015, we collected data on comorbidities, LOS, and discharge outcomes. Thirteen NCCs were studied. Negative binomial and Cox proportional regression models were applied to examine the association between NCCs and LOS and in-hospital death, respectively. Results: Approximately 53% of the patients had >= 1 NCCs. Diabetes and renal disease as well as anemia and renal disease co-existed more frequently than expected. Compared to having no NCCs, having one NCC was not associated with a significant increase in the likelihood of longer LOS [incidence rate ratio (IRR) 1.07; 95% Cl: 0.99-1.15; P=0.085] or in-hospital death [hazard ratio (HR) 1.11; 95% CI: 0.65-1.90; P=0.707]. However, having >= 2 NCCs was associated with 22% and 79% increased likelihood of longer LOS (IRR 1.22, 95% CI: 1.11-1.33; P<0.001) and in-hospital death (HR 1.79, 95% CI: 1.06-3.03; P=0.029), respectively, compared to not having any NCC. Certain NCC dyads [e.g., chronic pulmonary disease (CPD) + renal disease] exhibited multiplicative effect such that their impact on patients' LOS or survival exceeded the sum of the individual effects of the component NCCs. Conclusions: Over half of older patients hospitalized with NSTE-ACS had NCCs. A higher burden of NCCs correlated with increased LOS and lower survival. Contemporary ACS management guidelines need to recognize and incorporate protocols for the treatment of individuals with multiple chronic conditions to reduce the occurrence of adverse outcomes.