Nondisease-specific problems and all-cause mortality among older adults with CKD: the REGARDS Study

Abstract

Background and objectives: The term "nondisease-specific" has been used to describe problems that cross multiple domains of health and are not necessarily the result of a single underlying disease. Although individuals with reduced eGFR and elevated albumin-to-creatinine ratio have many comorbidities, the prevalence of and outcomes associated with nondisease-specific problems have not been well studied.

Design, setting, participants, & measurements: Participants included 3557 black and white United States adults ≥75 years of age from the Reasons for Geographic and Racial Differences in Stroke Study. Nondisease-specific problems included cognitive impairment, depressive symptoms, exhaustion, falls, impaired mobility, and polypharmacy. Hazard ratios for mortality over a median (interquartile range) of 5.4 (4.2-6.9) years of follow-up associated with one, two, or three to six nondisease-specific problems were calculated and stratified by eGFR (≥60, 45-59, and <45 ml/min per 1.73 m(2)) and separately, albumin-to-creatinine ratio (<30, 30-299, and ≥300 mg/g). Secondary outcomes included hospitalizations and emergency department visits over 1.8 (0.7-4.0) and 2.3 (0.9-4.7) years of follow-up, respectively.

Results: The prevalence of nondisease-specific problems was more common at lower eGFR and higher albumin-to-creatinine ratio levels. Within each eGFR and albumin-to-creatinine ratio strata, the risk for mortality was higher among those with a greater number of nondisease-specific problems. For example, among those with an eGFR=45-59 ml/min per 1.73 m(2), the multivariable adjusted hazard ratios (95% confidence intervals) for mortality associated with one, two, or three to six nondisease-specific problems were 1.17 (0.78 to 1.76), 1.95 (1.24 to 3.07), and 2.44 (1.39 to 4.27; P trend <0.001). Risk for hospitalization and emergency department visits was higher among those with more nondisease-specific problems within eGFR and albumin-to-creatinine ratio strata.

Conclusions: Among older adults, nondisease-specific problems commonly co-occur with reduced eGFR and elevated albumin-to-creatinine ratio. Identification of nondisease-specific problems may provide mortality risk information independent of measures of kidney function.

Keywords: CKD; epidemiology and outcomes; geriatric nephrology.