Analysis of Clostridium difficile infections after cardiac surgery: epidemiologic and economic implications from national data

Abstract

Objectives: Clostridium difficile infections (CDIs) have increased during the past 2 decades, especially among cardiac surgical patients, who share many of the comorbidity risk factors for CDI. Our objectives were to use a large national database to identify the regional-, hospital-, patient-, and procedure-level risk factors for CDI; and determine mortality, resource usage, and cost of CDIs in cardiac surgery.

Methods: Using the Nationwide Inpatient Sample database, we identified 349,122 patients who had undergone coronary artery bypass, valve, or thoracic-aortic surgery from 2004 to 2008. Of these, 2581 (0.75%) had been diagnosed with CDI. Multivariable regression analysis and the propensity method were used for risk adjustment.

Results: Compared with the West, CDIs were more likely to occur in the Northeast (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.12-1.47) and Midwest (OR, 1.27, 95% CI, 1.11-1.46) and less likely in the South (OR, 0.80; 95% CI, 0.70-0.90). Medium-size hospitals (OR, 0.88; 95% CI, 0.78-0.99) had a lower risk of CDI than did large hospitals. Older age (>75 years; OR, 2.59; 95% CI, 1.93-3.49), longer preoperative length of stay (OR, 1.51; 95% CI, 1.43-1.60), Medicare (OR, 1.21; 95% CI, 1.05-1.39) and Medicaid (OR, 1.60; 95% CI, 1.31-1.96) coverage, and more comorbidities were associated with CDI. Among the matched pairs, patients with CDIs had greater mortality (302 [12%] vs 187 [7.2%], P<.001), a longer median length of stay (21 vs 11 days, P<.001), and greater median hospital charges ($193,330 vs $112,245, P<.001). The cumulative incremental cost of CDIs was an estimated $212 million annually.

Conclusions: Our results have shown that CDI is associated with increased morbidity and resource usage. Additional work is needed to better understand the complex interplay among regional-, hospital-, and patient-level factors.