Predictors of time-to-nadir serum creatinine after drainage of bilaterally obstructed kidneys due to bladder cancer

Background

There are persistent controversies about the outcomes and benefits of drainage of malignant ureteral obstruction by percutaneous nephrostomy (PCN). This study aimed to assess the predictors of the time-to-nadir (TTN) of serum creatinine (SCr) levels after drainage of bilaterally obstructed kidneys (BOKs) due to bladder cancer (BC) by PCN.

Materials and methods

This prospective nonrandomized study included patients with BOKs due to BC treated by PCN between April 2019 and March 2022. The primary outcome measure was TTN.

Results

Of the 55 patients with a median age (range) of 66 years (47-86 years), 32 (58.2%) had a normal nadir SCr and 23 (41.8%) had a high nadir SCr within 21 days after drainage of BOKs due to BC. High nadir SCr was associated with a higher mean age (p = 0.011) and lower body mass index (BMI, p = 0.043). However, patients with normal nadir SCr had a significantly shorter TTN (p = 0.023) and an increased mean SCr trajectory (p < 0.001) during TTN. In multivariate analysis, low urine output at presentation (p = 0.021) and high BMI (p = 0.006) were associated with longer TTN. However, the mean parenchymal thickness (p = 0.428) and laterality of drainage (p = 0.466) were not associated with the mean TTN and SCr normalization rates. According to the modified Clavien-Dindo classification, 8 cases of hematuria were managed conservatively (grade 2), and 2 cases of PCN slippage were repositioned using local anesthesia (grade 3).

Conclusions

Despite the safety of PCN for drainage of BOKs due to BC, more than 41% of the patients failed to have a normal nadir SCr. Predrainage low urine output and high BMI were associated with longer TTN. Laterality of drainage had no significant effects on the TTN and SCr trajectory.