Hospital variation in postoperative infection and outcome after congenital heart surgery

Abstract

Background: Several initiatives aim to reduce postoperative infection across a variety of surgical patients as a means to improve overall quality of care and reduce variation across centers. However, the association of infection rates with hospital-level outcomes and resource utilization has not been well described. We evaluated this association across a multicenter cohort undergoing congenital heart surgery.

Methods: The Society of Thoracic Surgeons Congenital Heart Surgery Database was linked to resource utilization data from the Pediatric Health Information Systems Database for hospitals participating in both (2006 to 2010). Hospital-level infection rates (sepsis, wound infection, mediastinitis, endocarditis, pneumonia) adjusted for patient risk factors and case mix were calculated using Bayesian methodology, and association with hospital mortality rates, postoperative length of stay (LOS), and total costs evaluated.

Results: The cohort included 32,856 patients (28 centers); 3.7% had a postoperative infection. Across hospitals, the adjusted infection rate varied from 0.9% to 9.8%. Hospitals with the highest infection rates had longer (LOS) (13.2 vs 11.7 days, p < 0.001) and increased hospital costs ($71,100 vs $65,100, p < 0.001), but similar mortality rates (odds ratio 0.99, 95% confidence interval 0.80 to 1.21, p = 0.9). The proportion of variation in costs and LOS explained by infection was 15% and 6%, respectively.

Conclusions: Infection after congenital heart surgery contributes to prolonged LOS and increased costs on a hospital level. However, given that infection rates alone explained relatively little of the variation in these outcomes across hospitals, further study is needed to identify additional factors that may be targeted in initiatives to reduce variation and improve outcomes across centers.

Keywords: 20; 21; 4.

Fig 1

Adjusted infection rate across hospitals. (Boxes = adjusted estimates for each hospital; lines = 95% Bayesian probability intervals; dashed line = infection rate in overall cohort.)

Fig 2

Adjusted outcomes across hospitals ranked by infection rate. (A) Mortality; (B) postoperative LOS; (C) total hospital costs. See Table 2 for corresponding numeric data regarding adjusted outcomes across hospital infection groups. Of note, in the hospital-level analyses, patients who died within 7 days of surgery were excluded as described in Materials and Methods. (Boxes = adjusted estimates for each hospital; lines = 95% Bayesian probability intervals; dashed line = mean value in overall cohort; LOS = length of stay.)