Objective: Pneumonia is the most common healthcare-associated infection (HAI) in patients undergoing cardiac surgery. While current efforts have focused on risk factors and clinical implications of pneumonia, few have examined its overall financial impact. Our objective was to compare 90-day episode expenditures for Medicare patients undergoing coronary artery bypass graft surgery (CABG) with and without pneumonia.
Methods and Results: Using 2014-2015 Medicare Part A and B administrative claims data, we identified 50,550 patients undergoing isolated CABG. From this sample, we applied an established claims-based algorithm to identify 3,224 (6.4%) patients with new onset of pneumonia during their index admission and after their surgical procedure. Using generalized linear models, we found that average 90-day episode expenditures were 30% higher in patients with pneumonia ($55,442 vs. $42,745, p<0.001), adjusting for patient factors (age, sex, race, dual eligible status, and Elixhauser comorbidities) and hospital random intercepts (Table). Half of the added 90-day expenditures can be attributed to payments made for higher severity diagnosis-related group (DRG) billing codes in patients with pneumonia (+$6,275, p<0.001). The greatest relative increase in expenditures was for outlier hospitalization expenditures (+211%, p<0.001). Pneumonia was also associated with greater expenditures for post-discharge care, outpatient physician services, and readmissions, although these accounted for less than 20% of added expenditures. We estimated that 2% of all Medicare payments for CABG episodes during the study period are due to pneumonia.
Conclusion: New onset pneumonia is associated with 30% higher 90-day episode expenditures in CABG, independent of patient case mix. Prevention efforts could reduce excessive hospital inpatient utilization and save payers hundreds of millions of dollars every year.