Predictors of urinary tract infection after lower gastrointestinal surgery

Abstract

Background: Urinary tract infections (UTIs) cause postoperative morbidity in patients undergoing lower gastrointestinal (GI) surgery that can prolong postoperative hospital stays. In patients with a fever of unknown origin (FUO), clinicians ignore what to do while waiting for the results of the urine culture test. This study aimed to develop a nomogram predicting UTI in the case of postoperative FUO.

Methods: This observational, retrospective study included all consecutive patients from 1 November 2020 to 1 November 2021 undergoing lower-GI surgery at the Chirurgia Generale 3, University Hospital of Padua, Italy. A nomogram was created and externally validated in 90 consecutive patients undergoing urine culture tests for FUO at the Chirurgia Oncologica Unit, Veneto Institute of Oncology.

Results: In the development cohort, 109 (N = 109) patients performed a urine culture test for FUO, and 39 were diagnosed with UTI. In a multivariate analysis of patients who underwent urine culture tests for FUO, UTI was associated with female sex, older age, and duration of catheterization at the date of the urine culture test. We developed a nomogram to predict UTI in surgical patients with a C-index of 0.76. In the validation cohort, 90 consecutive patients, who had lower-GI surgery, underwent a urine culture test for FUO and were tested with this nomogram. In the validation cohort, the C-index of the nomogram for predicting a positive urine culture test was 0.71.

Conclusions and relevance: UTIs are a common problem in patients undergoing lower-GI surgery. A nomogram including the major risk factors may help to reduce the inappropriate use of antibiotics during the period awaiting the result of the urine culture test.

Keywords: Lower gastrointestinal surgery; Nomogram; Postoperative complications; Surgical outcomes; Urinary tract infection; Validation.