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.