Development of a Novel Clinical and Radiologic Risk Score to Predict Septic Complications After Urinary Decompression in Patients with Obstructive Uropathy

Abstract

Background: Well-defined clinical predictors of sepsis after upper tract drainage for obstructive uropathy are lacking. The study aim is to develop a data-driven score to predict risk of sepsis after decompression of the upper urinary tract. Materials and Methods: Complete clinical and radiologic data from 271 patients entering the emergency department for obstructive uropathy and submitted to stent/nephrostomy tube decompression were evaluated. The Charlson Comorbidity Index (CCI) was used to score comorbidities. The definition of sepsis was an increase in ≥2 Sequential Organ Failure Assessment points (or a postoperative persistently elevated score +1 additional increase) and documented blood or urine cultures. Descriptive statistics and stepwise multivariable logistic regression modeling with receiver operating characteristic analysis were performed to obtain a composite risk score to predict the risk of sepsis after surgery. This study was approved by our local Ethics Commitee (Prot. 25508). Results: Fifty-five (20.3%) patients developed sepsis. At multivariable analysis, CCI ≥2 (odds ratio [OR] 3.10; 95% confidence interval [CI] 1.36-7.04), maximum body temperature ≥38°C (OR 4.35; 95% CI 1.89-9.44), grade III-IV hydronephrosis (OR 2.37; 95% CI 1.10-4.98), HU of the dilated collecting system ≥7.0 (OR 4.47; 95% CI 2.03-9.81), white blood cells ≥15 × 10³/mmc (OR 2.77; 95% CI 1.24-6.19), and C-reactive protein ≥10 (OR 3.27; 95% CI 1.41-7.56) were independently associated with sepsis. The positive predictive value of a true sepsis increased incrementally as a function of number of positive variables, ranging from 1.6% to 100.0% among patients with 1 and 6 positive variables, respectively. Conclusion: Our risk score identifies accurately patients with an increased risk of sepsis after urinary decompression for obstructive uropathy, hence improving clinical management.

Keywords: Hounsfield units; emergency; hydronephrosis; obstructive uropathy; risk score; sepsis.