Little is known about disability in early-stage chronic kidney disease (CKD).
Cross-sectional national survey (National Health and Nutrition Examination Survey 1999–2006).
Setting and Participants
Community-based survey of 16,011 non-institutionalized U.S. civilian adults (≥20 years).
CKD, categorized as: no CKD, stages 1 and 2 [albuminuria and estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m2], and stages 3 and 4 (eGFR 15–59).
Self-reported disability, defined by limitations in working, walking, and cognition; and difficulties in activities of daily living (ADL), instrumental ADL, leisure and social activities, lower extremity mobility, and general physical activity.
Albuminuria and eGFR assessed from urine and blood samples; disability, demographics, access to care, and comorbid conditions assessed by standardized questionnaire.
Age-adjusted prevalence of reported limitations was generally significantly greater with CKD: e.g., difficulty with ADLs was reported by 17.6%, 24.7%, and 23.9% of older (≥65 years) and 6.8%, 11.9%, and 11.0% of younger (20–64 years) adults with no CKD, stages 1 and 2, and stages 3 and 4, respectively. CKD was also associated with greater reported limitations and difficulty in other activities after age adjustment, including instrumental ADL, leisure and social activities, lower extremity mobility, and general physical activity. Other demographics, socioeconomic status, and access to care generally only slightly attenuated the observed associations, particularly among older individuals; adjustment for cardiovascular disease, arthritis, and cancer attenuated most associations such that statistical significance was no longer achieved.
Inability to establish causality and possible unmeasured confounding.
CKD is associated with higher prevalence of disability in the United States. Age and other comorbid conditions account for most, but not all, of this association.