Association Between Kidney Function, Rehabilitation Outcome, and Survival in Older Patients Discharged From Inpatient Rehabilitation

Citation

Doyle EM, Sloan JM, Goodbrand JA, McMurdo MET, Donnan PT, McGilchrist MM, Frost H & Witham MD (2015) Association Between Kidney Function, Rehabilitation Outcome, and Survival in Older Patients Discharged From Inpatient Rehabilitation. American Journal of Kidney Diseases, 66 (5), pp. 768-774. https://doi.org/10.1053/j.ajkd.2015.04.041

Abstract
Background  Chronic kidney disease (CKD) is common in older people, but it is unclear if it affects survival and rehabilitation outcomes independent of comorbid conditions and physical function in this population.  Study Design  Cohort analysis of prospective, routinely collected, linked clinical data sets.  Setting & Participants  Patients discharged from a single inpatient geriatric rehabilitation center over a 12-year period.  Predictors  Admission estimated glomerular filtration rate (eGFR) category as a predictor of improvement in the 20-point Barthel score (activities of daily living measure) during rehabilitation; discharge eGFR category and Barthel score as predictors of survival postdischarge.  Outcomes  Survival postdischarge was modeled using Cox regression analyses, unadjusted and adjusted for age, sex, morbidities (ischemic heart disease, chronic obstructive pulmonary disease, stroke, diabetes, and heart failure), Barthel score and eGFR category on discharge, and serum calcium, hemoglobin, and albumin levels. The effect of admission eGFR category on change in Barthel score during admission was modeled using analysis of covariance, adjusted for admission, Barthel score, and comorbid conditions.  Results  3,012 patients were included; mean age, 84 years. 2,394 patients died during a mean follow-up of 8.3 years. Compared with patients with eGFR of 60 to 89mL/min/1.73m2, adjusted HRs for death were 1.26(95% CI, 1.13-1.40), 1.45 (95% CI, 1.29-1.63), and 1.68 (95% CI, 1.42-1.99) for eGFR categories of 45 to 59, 30 to 44, and<30mL/min/1.73m2, respectively. The relationship between discharge Barthel score and survival was similar within each discharge eGFR category (HRs of 0.95, 0.93, 0.92, 0.95, and 0.90 per Barthel scorepoint within eGFR categories of≥90, 60-89, 45-59, 30-44, and<30mL/min/1.73m2;Pfor interaction=0.2). Similar improvements in Barthel score between admission and discharge were seen for each admission eGFR category.  Limitations  Single-center study using routinely collected clinical data.  Conclusions  eGFR category and Barthel score are independent risk markers for survival in older rehabilitation patients, but advanced CKD does not preclude successful rehabilitation.

Keywords
Chronic kidney disease (CKD); reduced renal function; older adults; oldest old; geriatric; Barthel score; activities of daily living (ADLs); mortality; physical function; functional impairment; frailty; rehabilitation

Journal
American Journal of Kidney Diseases: Volume 66, Issue 5