Would the indwelling internal ureteral stent influence renal function despite relief of benign ureteral obstruction?

To assess the effect of internal ureteral stents (IUS) on renal function (RF) and to determine factors associated with the RF changes.

Between February 2009 and September 2012, 103 patients with bilateral or IUS in a solitary kidney were retrospectively analyzed. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration Equation (CKD-EPI). It was calculated from serum creatinine after adequate relief of obstruction (baseline) and at last follow-up. Deterioration of eGFR was considered if the last eGFR declined by >20% from the baseline value. Predictors of RF changes were detected using univariate and multivariate binary logistic regression analyses.

The mean patients' age was 54±14 years with males constituting 71.4% of the study population. During follow-up after IUS fixation, the median eGFR has declined from 50.6 mL/min/1.73 m(2) at baseline to 25 mL/min/1.73 m(2) at time of last follow-up (p<0.0001). Fifty-two (50.5%) patients experienced decline in their RF by >20% of baseline value. On multivariate analysis, positive urine culture (odds ratio [OR]: 3; p=0.026), baseline eGFR <60 mL/min (OR: 3.6; p=0.011), and extraluminal obstruction (OR: 2.9; p=0.035) were independent predictors of RF deterioration.

One half of patients with IUS lasting more than 3 months experienced RF deterioration during follow-up. This decline was significantly associated with positive urine cultures, presence of CKD, and extraluminal obstruction. All efforts should be exerted for active treatment of associated urinary tract infection and active follow-up of RF.