Association Between Postoperative Pneumonia and 90-Day Episode Payments and Outcomes Among Medicare Beneficiaries Undergoing Cardiac Surgery

Abstract

Background Postoperative pneumonia is the most common healthcare-associated infection in cardiac surgical patients, yet their impact across a 90-day episode of care remains unknown. Our objective was to examine the relationship between pneumonia and 90-day episode payments and outcomes among Medicare beneficiaries undergoing cardiac surgery. Methods and Results Medicare claims were used to identify beneficiaries with episodes of coronary artery bypass grafting (CABG; n=56 728) and valve surgery (n=56 377) across 1045 centers between April 2014 and March 2015. Using a published diagnosis code-based algorithm, we identified pneumonia in 6.4% CABG episodes and 6.6% of valve surgery episodes. We compared price-standardized 90-day episode payments and outcome measures (postoperative length of stay, discharge to postacute care, mortality, and readmission) between beneficiaries with and without pneumonia using hierarchical regression models, adjusting for patient factors and hospital random effects. Pneumonia was associated with 24.5% higher episode payments for CABG ($46 723 versus $37 496; P<0.001) and 26.5% higher episode payments for valve surgery ($61 544 versus $48 549; P<0.001). For both cohorts, pneumonia was significantly associated with longer postoperative length of stay (CABG: +4.1 days, valve: +5.6 days), more frequent discharge to postacute care (CABG: odds ratio [OR]=1.99, valve: OR=2.17), and higher rates of 30-day mortality (CABG: OR=2.42, valve: OR=2.57) and 90-day readmission (CABG: OR=1.20, valve: OR=1.25), all P<0.001. We compared episode payments and outcomes across terciles of pneumonia rates and found that high pneumonia rate hospitals had higher episode payments and poorer outcomes compared with episodes at low pneumonia rate hospitals in both CABG and valve surgery cohorts. Conclusions Postoperative pneumonia was associated with significantly higher 90-day episode payments and inferior outcomes at the patient and hospital level. Future work should examine whether reducing pneumonia after cardiac surgery reduces episode spending and improves outcomes, which could facilitate hospital success in value-based reimbursement programs.

Keywords: cardiac surgical procedures; medicare; outcomes assessment; pneumonia.