Background: The extent to which CKD is associated with 30-day and 1-year post ischemic stroke mortality and rehospitalization rates has not been well studied.
Methods: Data from 232,236 fee for service Medicare patients admitted with ischemic stroke to 1581 AHA GWTG-Stroke participating hospitals between January 2009 and December 2012 were analyzed. Estimated GFR in mL/min/1.73 m2 was determined based on the MDRD study equation categorized as: no CKD (GFR ≥60); stage 3a CKD (GFR 45-59); stage 3b CKD (GFR 30-44); stage 4 CKD, (GFR 15-29); stage 5 CKD (GFR <15 excluding those on dialysis). Dialysis was identified by ICD-9 codes. Multivariable Cox proportional hazards models adjusted for demographics, medical history, NIHSS, arrival hour, and hospital characteristics were used to determine the independent associations of CKD (reference group those without CKD) with mortality and readmission at 30 days and 1 year.
Results: After adjustment, 30-days poststroke mortality was highest among those with CKD stage 5 (HR 1.94, 95%CI 1.72-2.18), even after excluding in-hospital mortality and patients discharged to hospice (HR 2.09, 95%CI 1.66-2.63). Unadjusted 1-year mortality and readmission rates were highest among patients on dialysis (Figure). After adjustment, 1-year post-stroke mortality remained highest among patients on dialysis (HR 2.19, 95%CI 2.08-2.31), even after excluding in-hospital mortality and discharge to hospice (HR 2.65, 95%CI 2.49-2.81). For those discharged alive, 30-day and 1-year rehospitalization rates were also highest among patients on dialysis (HR 2.10, 95%CI 1.95-2.26; HR 2.55, 95%CI 2.44-2.66, respectively) as was the 30-day and 1-year composite of mortality and rehospitalization (HR 2.04, 95%CI 1.90-2.18; HR 2.46, 95% CI 2.36-2.56, respectively).
Conclusion: Among Medicare beneficiaries with acute ischemic stroke, poststroke mortality and rehospitalization varied by CKD stage and were highest among those with advanced CKD.