Incidence and Risk Factors for Dialysis Reinitiation among Patients with a History of Dialysis Dependency.

BACKGROUND AND OBJECTIVES: Recovery of kidney function after the start of maintenance dialysis can occur, but data on the incidence and risk factors for restarting dialysis after recovery of kidney function in this population are limited. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a retrospective study of adult Medicare beneficiaries who started dialysis between 2005 and 2015 according to the United States Renal Data System but who had recovery of kidney function (defined as a ≥90-day dialysis-free interval). We identified risk factors that were associated with the risk for the reinitiation of dialysis within a 3-year time frame following the recovery of kidney function and at any time during follow-up using Cox proportional hazards models. RESULTS: Of the 34,530 individuals previously on dialysis who had recovery of kidney function, 7217 (21%) restarted dialysis (absolute rate of 11.5 per 100 person-years) within 3 years of recovery of kidney function, and 9120 (26%) restarted dialysis during the entire follow-up period (absolute rate of 8.8 per 100 person-years). Among those with CKD stage 1 or 2 after recovery of kidney function, 10% of individuals restarted dialysis within 3 years of their recovery of kidney function, whereas among those with CKD stage 3, 4, or 5, 13%, 27%, and 36% of individuals restarted dialysis within 3 years of recovery of kidney function, respectively. Age at first dialysis, cause of kidney disease, history of CKD or nephrology care prior to starting dialysis, presence of heart failure, CKD stage following recovery of kidney function, and location of first dialysis initiation (inpatient versus outpatient) were some of the risk factors that were strongly associated with the risk of restarting dialysis after the recovery of kidney function. CONCLUSIONS: Over one in five patients with recovery of kidney function after kidney failure restarted dialysis within 3 years.

Post-Acute Kidney Injury Proteinuria and Subsequent Kidney Disease Progression: The Assessment, Serial Evaluation, and Subsequent Sequelae in Acute Kidney Injury (ASSESS-AKI) Study.

Importance: Among patients who had acute kidney injury (AKI) during hospitalization, there is a need to improve risk prediction such that those at highest risk for subsequent loss of kidney function are identified for appropriate follow-up. Objective: To evaluate the association of post-AKI proteinuria with increased risk of future loss of renal function. Design, Setting, and Participants: The Assessment, Serial Evaluation, and Subsequent Sequelae in Acute Kidney Injury (ASSESS-AKI) Study was a multicenter prospective cohort study including 4 clinical centers in North America included 1538 patients enrolled 3 months after hospital discharge between December 2009 and February 2015. Exposures: Urine albumin-to-creatinine ratio (ACR) quantified 3 months after hospital discharge. Main Outcomes and Measures: Kidney disease progression defined as halving of estimated glomerular filtration rate (eGFR) or end-stage renal disease. Results: Of the 1538 participants, 769 (50%) had AKI durring hospitalization. The baseline study visit took place at a mean (SD) 91 (23) days after discharge. The mean (SD) age was 65 (13) years; the median eGFR was 68 mL/min/1.73 m2; and the median urine ACR was 15 mg/g. Overall, 547 (37%) study participants were women and 195 (13%) were black. After a median follow-up of 4.7 years, 138 (9%) participants had kidney disease progression. Higher post-AKI urine ACR level was associated with increased risk of kidney disease progression (hazard ratio [HR], 1.53 for each doubling; 95% CI, 1.45-1.62), and urine ACR measurement was a strong discriminator for future kidney disease progression (C statistic, 0.82). The performance of urine ACR was stronger in patients who had had AKI than in those who had not (C statistic, 0.70). A comprehensive model of clinical risk factors (eGFR, blood pressure, and demographics) including ACR provided better discrimination for predicting kidney disease progression after hospital discharge among those who had had AKI (C statistic, 0.85) vs those who had not (C statistic, 0.76). In the entire matched cohort, after taking into account urine ACR, eGFR, demographics, and traditional chronic kidney risk factors determined 3 months after discharge, AKI (HR, 1.46; 95% CI, 0.51-4.13 for AKI vs non-AKI) or severity of AKI (HR, 1.54; 95% CI, 0.50-4.72 for AKI stage 1 vs non-AKI; HR, 0.56; 95% CI, 0.07-4.84 for AKI stage 2 vs non-AKI; HR, 2.24; 95% CI, 0.33-15.29 for AKI stage 3 vs non-AKI) was not independently associated with more rapid kidney disease progression. Conclusions and Relevance: Proteinuria level is a valuable risk-stratification tool in the post-AKI period. These results suggest there should be more widespread and routine quantification of proteinuria after hospitalized AKI.