Impact of risk factors on in-hospital mortality for octogenarians undergoing cardiac surgery.

BACKGROUND: Octogenarians undergoing cardiac surgery have higher mortality than their younger counterparts. OBJECTIVES: To determine if various risk factors have the same effect on mortality in octogenarians as in younger patients. METHODS: The National Inpatient Sample data set from 2004 to 2014 was queried to select patients aged 65 years and older who underwent either coronary artery bypass grafting (CABG), valvular heart surgery (VHS), or both (CABG + VHS) within 10 days of hospital admission. The patients were divided into two groups 65-79 years and 80 years and greater. Hospital mortality, patient demographics, comorbidities, and type of hospital admission was evaluated and compared using χ2 and multivariable logistic regressions. RESULTS: About 397,713 patients were identified including 86,345 (21.7%) aged 80 and above. Octogenarians had higher in-hospital mortality for all procedures: CABG (4.94% vs. 2.39%, p < .001), VHS (5.49% vs. 4.08%, p < .001), and CABG + VHS (7.59% vs. 5.95%, p < .001), and this relationship persisted when gender, race, comorbidities, and type of hospital admission were controlled for: CABG (odds ratio [OR] = 1.71; 95% confidence interval [CI] 1.62-1.81); VHS (OR = 1.18; 95% CI 1.11-1.27); and CABH + VHS (OR = 1.17; 95%CI 1.10-1.26). Female gender, renal, or heart failure, nonelective admission, and CABG + VHS were associated with increased risk of in-hospital mortality. Octogenarians had higher rates of these factors (p < .001). The effect size of renal and heart failure and type of surgery was smaller for octogenarians. CONCLUSIONS: Octogenarians undergoing cardiac surgery have higher rates of nonelective admissions, renal and heart failure, and female gender, which are most strongly associated with in-hospital mortality. Differing effect sizes suggest that certain risk factors, such as renal and heart failure, contribute more to mortality in younger patients.