Quality Reporting Windows May Not Capture the Effects of Surgical Site Infections After Orthopaedic Surgery

Abstract

Background: Postoperative surgical site infections (SSIs) and the associated complications impact morbidity and mortality and result in substantial burden to the health-care system. These complications are typically reported during the 90-day surveillance period, with implications for reimbursement and quality measurement; however, the long-term effects of SSI are not routinely assessed. We evaluated the long-term effects of SSI on health-care utilization and cost following orthopaedic surgery in an observational cohort study.

Methods: Patients in the Veterans Affairs health-care system who underwent an orthopaedic surgical procedure were included. The exposure of interest was an SSI within 90 days after the index procedure. The primary outcome was health-care utilization in the 2 years after discharge. Data for inpatient admission, inpatient days, outpatient visits, emergency room visits, total costs, and subsequent surgeries were also obtained. After adjusting for factors affecting SSI, we examined differences in each health-care utilization outcome by postoperative SSI occurrence and across time with use of differences-in-differences analysis. Cost differences were modeled with use of a gamma distribution with a log link.

Results: A total of 96,983 patients were included, of whom 4,056 (4.2%) had an SSI within 90 days of surgery. After adjusting for factors known to impact SSI and preoperative health-care utilization, SSI was associated with a greater risk of outpatient visits (relative risk [RR], 1.29; 95% confidence interval [CI], 1.26 to 1.32), emergency room visits (RR, 1.18; 95% CI, 1.15 to 1.21), and inpatient admission (RR, 1.35; 95% CI, 1.32 to 1.38) at 2 years postoperatively. The average cost among patients with an SSI was $148,824 ± $268,358 compared with $42,125 ± $124,914 among those without an SSI (p < 0.001). In the adjusted analysis, costs for patients with an SSI were 64% greater at 2 years compared with those without an SSI (RR, 1.64; 95% CI, 1.57 to 1.70). Overall, of all subsequent surgeries conducted within the 2-year postoperative period, 37% occurred within the first 90 days.

Conclusions: The reported effects of a postoperative SSI on health-care utilization and cost are sustained at 2 years post-surgery-a long-term impact that is not recognized in quality-measurement models. Efforts, including preoperative care pathways and optimization, and policies, including reimbursement models and risk-adjustment, should be made to reduce SSI and to account for these long-term effects.

Level of evidence: Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.