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

Abstract

Background and Objectives: About 30% of patients with acute kidney injury (AKI) may require ongoing dialysis in the outpatient setting after hospital discharge. A 2017 CMS 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 AKI dialysis patients and non-AKI incident dialysis patients. Design, setting, participants, and measurements: Retrospective cohort design, using 2017 Medicare Claims to follow outpatient AKI dialysis patients 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: 10,821 of 401,973 (3%) Medicare dialysis patients had at least one AKI claim, and 52,626 patients were Medicare non-AKI incident dialysis patients. AKI dialysis patients were more likely to be White (76% vs 70%), non-Hispanic (92% vs 87%), and age 60 or greater (82% vs 72%) compared to non-AKI incident dialysis patients. Unadjusted mortality was markedly higher for AKI dialysis patients compared to non-AKI incident dialysis patients. 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 AKI dialysis patients vs non-AKI incident dialysis patients was lower throughout month 4 (1.5 v .60, 1.20 v 0.84, 1.00 v 0.80, 0.95 v 0.74, all P<0.001 which persisted through month 7. Overall adjusted mortality risk was 22% higher for AKI dialysis patients (1.22, CI 1.17, 1.27). Conclusions: In fully adjusted analyses AKI dialysis patients had higher early mortality compared to 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.

Early Comprehensive Kidney Care in Dialysis-Requiring Acute Kidney Injury Survivors: A Populational Study

“…Whereas, only 19% of them recovered kidney function to the extent without the need of further dialysis. Furthermore, 16% of D-AKI patients died (7). In a study involving intensive care patients surviving D-AKI, the subsequent risk of ESRD for D-AKI patients was 8.5%, within 180 days following ICU admission, compared with 0.1% for non-D-AKI ICU patients.…”

“…Dialysis-Requiring Acute Kidney Injury (D-AKI) is one of the most severe entities of AKI KDIGO stage 3 (6), with high rates of mortality and ESRD (7,8). A retrospective study found that 66% of D-AKI patients had no recovery in kidney function, and they required chronic dialysis.…”

Dialyzing Acute Kidney Injury Patients after Hospital Discharge

“…In this issue of CJASN , Dahlerus et al (1) report the results of a retrospective cohort study using 2017 outpatient dialysis Medicare claims to examine patient characteristics and mortality in patients with dialysis-requiring AKI discharged to receive outpatient dialysis compared with the non-AKI incident dialysis population. The authors found that patients with dialysis-requiring AKI had more comorbidities documented.…”

“…The study by Dahlerus et al (1) distinguishes itself from similar prior studies by being national in scope (whereas most prior outpatient dialysis-requiring AKI studies were on the basis of single-center or single–health care system data only). Another strength is the nonreliance on the Centers for Medicare & Medicaid Services (CMS) Medical Evidence 2728 Form to identify AKI.…”

“…In summary, Dahlerus et al (1) provide evidence that in the contemporary era, patients with dialysis-requiring AKI make up a sizable fraction of new patients requiring care in the outpatient dialysis unit. These patients experience high rates of mortality but simultaneously have the potential for much better outcomes than other patients initiating treatment in the outpatient dialysis unit because of possible kidney function recovery to come off dialysis completely.…”