Predictors of nadir serum creatinine after drainage of bilaterally obstructed kidneys due to different etiologies

Purpose To identify the predictors of nadir serum creatinine (SCr) after drainage of bilaterally obstructed kidneys (BOKs) by different modes: double-J stent (JJ) versus percutaneous nephrostomy (PCN) and unilateral versus bilateral drainage. Methods A prospective non-randomized study was performed on patients with BOKs and raised SCr during December 2019–November 2021. Relevant variables were studied for improvement and non-improvement and for benign and malignant underlying obstructions (BUO and MUO). Results This study included 107 patients with BOKs including 68 (63.6%) males and 39 (36.4%) females. After drainage, 86 (80.4%) patients get improved, while 21 (19.6%) patients failed to reach a nadir SCr. Drainage by PCN was significantly higher in MUO, while JJ was significantly higher in BUO ( p < 0.001). Also, bilateral drainage was a significant predictor of improvement in MUO ( p = 0.03). In contrast, mode of drainage had no significant effect on improvement in BUO ( p = 0.84), but bilateral drainage was a significant factor of rapid time to nadir ( p = 0.02). Univariate analyses revealed no significant effects on the improvement in SCr from the studied variables, except the male gender ( p = 0.01), old age ( p < 0.001), MUO ( p = 0.01), unilateral drainage ( p < 0.001), and use of PCN for drainage ( p < 0.001). By multivariate analysis, unilateral drainage ( p = 0.01) and MUO ( p < 0.001) were independent predictors of non-improvement in patients with BOKs. Conclusions Male gender, old age, MUO, unilateral drainage, and drainage by PCN were significant predictors of non-improvement in SCr after drainage of BOKs. However, unilateral drainage and MUO were the only independent predictors of non-improvement.