Sy‐Go, Janina Paula T.

Background Little is known about the prognostic significance of monoclonal gammopathy of undetermined and renal significance (MGUS and MGRS) in patients with CKD. The objective of this study was to determine the clinical and kidney outcomes of patients with CKD with either MGUS or MGRS compared with those with CKD without MGUS or MGRS. Methods We conducted a retrospective cohort study from 2013 to 2018. Patients who had both CKD diagnosis and monoclonal testing were identified. Patients were divided into MGRS, MGUS, and no monoclonal gammopathy groups. Cumulative incidence functions and Cox proportional hazards regression were used to model time to event data and to evaluate the association between monoclonal gammopathy status and risk of kidney failure, with death treated as a competing risk. Results Among 1535 patients, 59 (4%) had MGRS, 648 (42%) had MGUS, and 828 (54%) had no monoclonal gammopathy. Unadjusted analysis showed that compared with no monoclonal gammopathy patients, patients with MGRS were at higher risk of kidney failure (hazard ratio [HR] [95% confidence interval]: 2.5 [1.5 to 4.2] but not patients with MGUS (HR [95% confidence interval]: 1.3 [0.97 to 1.6]), after taking death into account as a competing risk. However, in the multivariable analysis, after adjusting for age, sex, eGFR, proteinuria, and Charlson Comorbidity Index, the risk of progression to kidney failure (with death as competing risk) in the MGRS group was no longer statistically significant (HR: 0.9 [0.5 to 1.8]). The same was also true for the MGUS group compared with the group with no monoclonal gammopathy (HR: 1.3 [0.95 to 1.6]). When evaluating the association between MGUS/MGRS status and overall survival, MGRS was significantly associated with mortality in fully adjusted models compared with the group with no monoclonal gammopathy, while MGUS was not. Conclusions After adjusting for traditional risk factors, MGUS/MGRS status was not associated with a greater risk of kidney failure, but MGRS was associated with a higher risk of mortality compared with patients with no monoclonal gammopathy.

The combination of endocrine therapy and cyclin-dependent kinase (CDK) 4/6 inhibitors is currently one of the preferred first-line regimens for patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer. CDK 4/6 inhibitors can cause serum creatinine (SCr) elevation and corresponding estimated glomerular filtration rate (eGFR) reduction without affecting kidney function by inhibiting tubular secretory transporters in the kidneys—a phenomenon called pseudo-acute kidney injury (pseudo-AKI). We report a case of a 69-year old woman found to have elevated SCr while on ribociclib for treatment of metastatic breast cancer. Further evaluation with cystatin C-based eGFR and measured GFR by urinary iothalamate clearance revealed values close to her baseline Cr-based eGFR prior to initiation of treatment with ribociclib. She was therefore diagnosed with ribociclib-induced pseudo-AKI. Treatment with ribociclib was continued with steady favorable response. This case highlights that, in addition to true AKI, ribociclib can cause pseudo-AKI. Alternative methods of kidney function assessment may be necessary in patients who develop elevated SCr while on this medication to help discriminate between artifactual and true kidney function impairment. Doing so can help avoid unnecessary work-up and/or premature discontinuation of the treatment.

Background: The objectives of this study were to classify patients with serum magnesium derangement on hospital admission into clusters using unsupervised machine learning approach and to evaluate the mortality risks among these distinct clusters. Methods: Consensus cluster analysis was performed based on demographic information, principal diagnoses, comorbidities, and laboratory data in hypomagnesemia (serum magnesium ≤ 1.6 mg/dL) and hypermagnesemia cohorts (serum magnesium ≥ 2.4 mg/dL). Each cluster’s key features were determined using the standardized mean difference. The associations of the clusters with hospital mortality and one-year mortality were assessed. Results: In hypomagnesemia cohort (n = 13,320), consensus cluster analysis identified three clusters. Cluster 1 patients had the highest comorbidity burden and lowest serum magnesium. Cluster 2 patients had the youngest age, lowest comorbidity burden, and highest kidney function. Cluster 3 patients had the oldest age and lowest kidney function. Cluster 1 and cluster 3 were associated with higher hospital and one-year mortality compared to cluster 2. In hypermagnesemia cohort (n = 4671), the analysis identified two clusters. Compared to cluster 1, the key features of cluster 2 included older age, higher comorbidity burden, more hospital admissions primarily due to kidney disease, more acute kidney injury, and lower kidney function. Compared to cluster 1, cluster 2 was associated with higher hospital mortality and one-year mortality. Conclusion: Our cluster analysis identified clinically distinct phenotypes with differing mortality risks in hospitalized patients with dysmagnesemia. Future studies are required to assess the application of this ML consensus clustering approach to care for hospitalized patients with dysmagnesemia.

AbstractPeritoneal–mediastinal communication is a rare complication of peritoneal dialysis (PD). We report the first case of peritoneal–mediastinal communication complication in a 36‐year‐old Caucasian man on continuous cycler peritoneal dialysis (CCPD) after undergoing cardiac surgery. He developed end‐stage kidney disease (ESKD) due to calcineurin inhibitor nephrotoxicity and BK virus nephropathy in the setting of prior heart transplantation. He was initially started on intermittent hemodialysis (iHD) and was switched to CCPD 1 year later. He presented with increased drainage from his sternal incision site and reduced ultrafiltration. A contrast‐enhanced chest computed tomography scan revealed an anterior chest wall subcutaneous fluid collection. He was found to have a peritoneal–mediastinal communication intraoperatively. He was successfully managed with “low‐volume” PD by using reduced fill volumes for all his exchanges and did not require transition to iHD. He also had no vascular access options because of multiple prior thromboses, which would have made transitioning to iHD not feasible. This case further highlights the complex management of an ESKD patient who cannot do iHD and only do low‐volume PD because of a surgical complication and the need for a multidisciplinary approach to ensure appropriate patient care.