Incidence and Impact of Surgical Site Infections on Length of Stay and Cost of Care

Introduction: Surgical site infections (SSIs) are associated with increased morbidity and mortality; however, current incidence rates of SSIs across procedures and their impact on healthcare delivery are unknown.

This study identified the incidence of SSIs in patients undergoing open surgical procedures in the United States and examined the impact of these SSIs on length of stay (LOS) and costs.

Methods: Retrospective analyses using data from Medicare (2019) and Premier (2019-2020), a national all-payer hospital database, identified patients who underwent common open surgical procedures. SSIs occurring during index hospitalization or within 90 days of discharge were identified by diagnostic related group and ICD-10 diagnosis codes. Patients with SSIs were matched to those without SSIs using propensity scoring to calculate incremental LOS and costs attributable to SSIs. The mean LOS and costs attributable to SSIs for the index admission, readmissions, and outpatient visits were summed by surgery and Charlson Comorbidity Index score to estimate the overall impact of an SSI on LOS and costs across health care settings.

Results: SSI rates were 2.0% for the 1,546,574 Medicare and 1.7% for the 781,991 Premier open surgeries. Of patients with an SSI, an estimated 19.7% of Medicare and 24.1% of Premier patients had an SSI occur during the index admission resulting in an additional 11 and 12 days of LOS and $19,563 and $34,353 in costs, respectively. Approximately 66.4% of Medicare and 57.8% of Premier patients with an SSI had SSI-related readmissions incurring an additional 10.7 and 8.3 days of LOS and $21,624 and $21,742 in costs, respectively.

For all patients with an SSI, the mean incremental LOS and cost per SSI, including index admission, readmissions, and costs of SSI-related outpatient visits were 9.3 days and $18,328 for Medicare patients and 7.7 days and $21,279 for Premier patients.

Conclusions: SSIs occur infrequently but generate substantial increases in LOS and cost. Extrapolating study findings nationally results in more than 404,000 additional hospital days and $1.1 billion in costs attributable to SSIs in patients undergoing open surgical procedures annually. Implementation of interventions that reduce SSIs, particularly in high-risk patients, may decrease healthcare utilization and costs.