Implication of acute tubular injury in minimal change nephrotic syndrome

While acute tubular injury (ATI) is known to occur in a significant number of minimal change disease (MCD) nephrotic syndrome cases with acute kidney injury (AKI), the clinical significance is not certain, and AKI may also occur without ATI. This study aimed to evaluate whether the severity of AKI defined by Kidney Disease Improving Global Outcomes (KDIGO) criteria correlated with the presence or severity of ATI in a series of adult patients with MCD. We also looked at whether time to remission of nephrotic syndrome (NS) with treatment correlated with the presence of ATI in those with and without AKI. We excluded patients with secondary MCD. Of 61 patients, 20 had AKI (33%). ATI was significantly more likely to occur in those with AKI than in those without AKI (60 vs. 24%). Overall, the severity of AKI did not clearly correspond with the severity of ATI. Remission rates at 4 weeks were lowest (25%) in those with both AKI and ATI, while they were highest (100%) in those with neither AKI nor ATI. Patients with AKI but no ATI and those with no AKI but having ATI were intermediate in remission rates and similar to each other (60 and 62%, respectively). The time to remission in the group of those without AKI was significantly longer in those with ATI than in those without (p = 0.0027), but the numerical difference in remission did not reach statistical significance in the smaller group of AKI patients. Patients with ATI were older and more often male than those without ATI. It appears that having ATI may predict a slower remission rate in MCD though the reason for this is unclear. The different demographics of those with ATI may also play a role.