Background Immune checkpoint inhibitor-associated acute kidney injury (ICPi-AKI) has emerged as an important toxicity among patients with cancer. Methods We collected data on 429 patients with ICPi-AKI and 429 control patients who received ICPis contemporaneously but who did not develop ICPi-AKI from 30 sites in 10 countries. Multivariable logistic regression was used to identify predictors of ICPi-AKI and its recovery. A multivariable Cox model was used to estimate the effect of ICPi rechallenge versus no rechallenge on survival following ICPi-AKI. Results ICPi-AKI occurred at a median of 16 weeks (IQR 8–32) following ICPi initiation. Lower baseline estimated glomerular filtration rate, proton pump inhibitor (PPI) use, and extrarenal immune-related adverse events (irAEs) were each associated with a higher risk of ICPi-AKI. Acute tubulointerstitial nephritis was the most common lesion on kidney biopsy (125/151 biopsied patients [82.7%]). Renal recovery occurred in 276 patients (64.3%) at a median of 7 weeks (IQR 3–10) following ICPi-AKI. Treatment with corticosteroids within 14 days following ICPi-AKI diagnosis was associated with higher odds of renal recovery (adjusted OR 2.64; 95% CI 1.58 to 4.41). Among patients treated with corticosteroids, early initiation of corticosteroids (within 3 days of ICPi-AKI) was associated with a higher odds of renal recovery compared with later initiation (more than 3 days following ICPi-AKI) (adjusted OR 2.09; 95% CI 1.16 to 3.79). Of 121 patients rechallenged, 20 (16.5%) developed recurrent ICPi-AKI. There was no difference in survival among patients rechallenged versus those not rechallenged following ICPi-AKI. Conclusions Patients who developed ICPi-AKI were more likely to have impaired renal function at baseline, use a PPI, and have extrarenal irAEs. Two-thirds of patients had renal recovery following ICPi-AKI. Treatment with corticosteroids was associated with improved renal recovery.

Background Immune checkpoint inhibitors (ICPi) are a novel and promising anti-cancer therapy. There are limited data on the incidence, risk factors and outcomes of acute kidney injury (AKI) in patients receiving ICPi. Methods We conducted a cohort study of patients receiving ICPi at our center between 2010 and 2017 via electronic health record. The primary outcome was AKI (increase of >50% from baseline serum creatinine (sCr)). Risk factors for AKI were assessed using logistic regression. Survival among those with and without AKI was compared using the Kaplan-Meier method. Results Among 309 patients on ICPi, 51 (16.5%) developed AKI (Kidney Disease Improving Global Outcomes (KDIGO) stages 1: 53%, 2: 22%, 3: 25%). AKI was associated with other immune-related adverse events (IRAE) (OR 3.2, 95% CI 1.6 to 6; p<0.001), hypertension (OR 4.3, 95% CI 1.8 to 6.1; p<0.001) and cerebrovascular disease (OR 9.2; 95% CI 2.1 to 40; p<0.001). Baseline sCr, cancer, and ICPi type was not associated with AKI. Use of angiotensin-converting enzyme inhibitors/angiotensin-receptor blockers (OR 2.9; 95% CI 1.5 to 5.7; p=0.002), diuretics (OR 4.3; 95% CI 1.9 to 9.8; p<0.001), and corticosteroid treatment (OR 1.9; 95% CI 1.1 to 3.6; p=0.03) were associated with AKI. In the multivariable analysis, AKI was associated only with other IRAE (OR 2.82; 95% CI 1.45 to 5.48; p=0.002) and hypertension (OR 2.96; 95% CI 1.33 to 6.59; p=0.008). AKI was not associated with increased risk of mortality (HR 1.1; 95% CI: 0.8 to 1.6; p=0.67). ICPi nephrotoxicity was attributed via biopsy or nephrologist assessment in 12 patients (six interstitial nephritis, two membranous nephropathy, two minimal change disease, and two thrombotic microangiopathy). Subsequent doses of ICPi were administered to 12 patients with prior AKI, with one (8.3%) having recurrent AKI. Conclusion AKI is a common complication in patients receiving ICPi treatment. The development of other IRAE and previous diagnosis of hypertension were associated with increased AKI risk. AKI was not associated with worse survival. Distinguishing kidney IRAE from other causes of AKI will present a frequent challenge to oncology and nephrology practitioners. Kidney biopsy should be considered to characterize kidney lesions and guide potential therapy.

Immune checkpoint inhibitors (ICIs) are increasingly used to treat cancers. Kidney immune-related adverse events (IRAEs) are now well recognized, with the incidence of IRAEs ranging from 2% to 5%. Most of the initial data related to kidney IRAEs have focused on acute interstitial nephritis (AIN). There are minimal data on the types and relative frequencies of glomerular diseases associated with ICIs, their treatment, and outcomes. We performed a systematic review and meta-analysis of all biopsy-proven published cases/series of glomerular pathology associated with ICIs. We searched the MEDLINE, EMBASE, and Cochrane databases from inception to February 2020. We abstracted patient-level data, including demographics, cancer and ICI therapy details, and characteristics of kidney injury. After screening, 27 articles with 45 cases of biopsy-confirmed ICI-associated glomerular disease were identified. Several lesion types were observed, with the most frequent being pauci-immune glomerulonephritis (GN) and renal vasculitis (27%), podocytopathies (24%), and complement 3 GN (C3GN; 11%). Concomitant AIN was reported in 41%. Most patients had ICIs discontinued (88%), and nearly all received corticosteroid treatment (98%). Renal replacement therapy (RRT) was required in 25%. Most patients had full (31%) or partial (42%) recovery from acute kidney injury (AKI), although 19% remained dialysis-dependent, and approximately one-third died. Complete or partial remission of proteinuria was achieved in 45% and 38%, respectively. Multiple forms of ICI-associated glomerular disease have been described. Pauci-immune GN, podocytopathies, and C3GN are the most frequently reported lesions. ICI-associated glomerular disease may be associated with poor kidney and mortality outcomes. Oncologists and nephrologists must be aware of glomerular pathologies associated with ICIs and consider obtaining a kidney biopsy specimen when features atypical for AIN are present.

Background and objectives: Survivors of AKI are at higher risk of CKD and death, but few patients see a nephrologist after hospital discharge. Our objectives during this 2-year vanguard phase trial were to determine the feasibility of randomizing survivors of AKI to early follow-up with a nephrologist or usual care, and to collect data on care processes and outcomes. Design, setting, participants, & measurements: We performed a randomized controlled trial in patients hospitalized with Kidney Disease Improving Global Outcomes (KDIGO) stage 2–3 AKI at four hospitals in Toronto, Canada. We randomized patients to early nephrologist follow-up (standardized basket of care that emphasized BP control, cardiovascular risk reduction, and medication safety) or usual care from July 2015 to June 2017. Feasibility outcomes included the proportion of eligible patients enrolled, seen by a nephrologist, and followed to 1 year. The primary clinical outcome was a major adverse kidney event at 1 year, defined as death, maintenance dialysis, or incident/progressive CKD. Results: We screened 3687 participants from July 2015 to June 2017, of whom 269 were eligible. We randomized 71 (26%) patients (34 to nephrology follow-up and 37 to usual care). The primary reason stated for declining enrollment included hospitalization-related fatigue (n=65), reluctance to add more doctors to the health care team (n=59), and long travel times (n=40). Nephrologist visits occurred in 24 of 34 (71%) intervention participants, compared with three of 37 (8%) participants randomized to usual care. The primary clinical outcome occurred in 15 of 34 (44%) patients in the nephrologist follow-up arm, and 16 of 37 (43%) patients in the usual care arm (relative risk, 1.02; 95% confidence interval, 0.60 to 1.73). Conclusions: Major adverse kidney events are common in AKI survivors, but we found the in-person model of follow-up posed a variety of barriers that was not acceptable to many patients. Clinical Trial registry name and registration number: Nephrologist Follow-up versus Usual Care after an Acute Kidney Injury Hospitalization (FUSION), NCT02483039 CJASN 16: 1005–1014, 2021. doi: https://doi.org/10.2215/CJN.17331120