The Impacts of Deep Surgical Site Infections on Readmissions, Length of Stay, and Costs: A Matched Case–Control Study Conducted in an Academic Hospital in the Netherlands

Objective: This study aimed to evaluate the impacts of deep surgical site infections (dSSIs) regarding hospital readmissions, prolonged length of stay (LoS), and estimated costs. Patients and Methods: We designed and applied a matched case–control observational study using the electronic health records at the University Medical Center Groningen in the Netherlands. We compared patients with dSSI and non-SSI, matched on the basis of having similar procedures. A prevailing topology of surgeries categorized as clean, clean-contaminated, contaminated, and dirty was applied. Results: Out of a total of 12,285 patients, 393 dSSI were identified as cases, and 2864 patients without SSIs were selected as controls. A total of 343 dSSI patients (87%) and 2307 (81%) controls required hospital readmissions. The median LoS was 7 days (P 25 -P 75 : 2.5– 14.5) for dSSI patients and 5 days (P 25 -P 75 : 1– 9) for controls ( p -value: < 0.001). The estimated mean cost per hospital admission was € 9,016 (SE± 343) for dSSI patients and € 5,409 (SE± 120) for controls (p< 0.001). Independent variables associated with dSSI were patient’s age ≥ 65 years (OR: 1.334; 95% CI: 1.036– 1.720), the use of prophylactic antibiotics (OR: 0.424; 95% CI: 0.344– 0.537), and neoplasms (OR: 2.050; 95% CI: 1.473– 2.854). Conclusion: dSSI is associated with increased costs, prolonged LoS, and increased readmission rates. Elevated risks were seen for elderly patients and those with neoplasms. Additionally, a protective effect of prophylactic antibiotics was found.