Acute Kidney Injury Requiring Dialysis and Incident Dialysis Patient Outcomes in US Outpatient Dialysis Facilities

Background and objectives About 30% of patients with AKI may require ongoing dialysis in the outpatient setting after hospital discharge. A 2017 Centers for Medicare & Medicaid Services policy change allows Medicare beneficiaries with AKI requiring dialysis to receive outpatient treatment in dialysis facilities. Outcomes for these patients have not been reported. We compare patient characteristics and mortality among patients with AKI requiring dialysis and non-AKI incident dialysis patients. Design, setting, participants, & measurements We used a retrospective cohort design with 2017 Medicare claims to follow outpatients with AM requiring dialysis and non-AKI incident dialysis patients up to 365 days. Outcomes are unadjusted and adjusted mortality using Kaplan-Meier estimation for unadjusted survival probability, Poisson regression for monthly mortality, and Cox proportional hazards modeling for adjusted mortality. Results In total, 10,821 of 401,973 (3%) AKI Medicare patients requiring dialysis had at least one AM claim, and 52,626 patient; were non-AKI Medicare incident dialysis patients. Patient; with AKI requiring dialysis were more likely to be White (76% versus 70%), non-Hispanic (92% versus 87%), and age 60 or older (82% versus 72%) compared with non-AKI incident dialysis patients. Unadjusted mortality was markedly higher for patients with AM requiring dialysis compared with patients with non-AKI incident dialysis. Adjusted mortality differences between both cohorts persisted through month 4 of the follow-up period (all P-0.01), then declined and were no longer statistically significant. Adjusted monthly mortality stratified by Black and other race between patients with AM requiring dialysis and non-AKI incident dialysis patients was lower throughout month 4 (1.5 versus 0.60, 1.20 versus 0.84, 1.00 versus 0.80, and 0.95 versus 0.74; all P<0.001), which persisted through month 7. Overall adjusted mortality risk was 22% higher for patients with AKI requiring dialysis (1.22; 95% confidence interval, 1.17 to 1.27). Conclusions In fully adjusted analyses, patients with AKI requiring dialysis had higher early mortality compared with non-AKI incident dialysis patients, but these differences declined after several months. Differences were also observed by age, race, and ethnicity within both patient cohorts.