Chronic Inflammation, Albuminuria, and Functional Disability in Older Adults with Cardiovascular Disease: the National Health and Nutrition Examination Survey, 1999-2008

Objective: Although C-reactive protein (CRP) and albuminuria are well-documented cardiovascular risk markers, the functional implications of these biomarkers and their combination on functional disability and metabolic risks in patients with cardiovascular disease (CVD) are unknown.

Methods: Data were from 1403 adults (≥60 years, mean 73.2 years) with CVD, ascertained by self-reported diagnosis of angina, coronary heart disease, congestive heart failure, myocardial infarction or stroke, in the National Health and Nutrition Examination Survey 1999-2008. Disability in activities of daily living (ADL), instrumental activities of daily living (IADL), leisure and social activities (LSA), general physical activities (GPA), and lower-extremity mobility (LEM) were obtained from self-reports. The urinary albumin-to-creatinine ratio (UACR) was calculated by dividing the urinary albumin value by the urinary creatinine concentration. CRP levels were quantified by latex-enhanced nephelometry.

Results: Inflammation and albuminuria were associated with disability. In the full-adjusted models, odds ratios (ORs) (95% confidence intervals [CIs]) of disability in ADL, LSA, and LEM were 1.60 (1.13-2.28), 1.76 (1.22-2.55) and 2.31 (1.62-3.31), respectively, comparing participants in the highest CRP quartile to the lowest (p values for trend across CRP quartiles<0.01). The corresponding ORs (95% CI) for disability in ADL, IADL, LSA, and LEM were 1.71 (1.20-2.45), 1.72 (1.21-2.45), 1.46 (1.01-2.12) and 2.50 (1.73-3.62), respectively, comparing participants in the highest UACR quartile to the lowest. We found combined association of inflammation and albuminuria with disability and with metabolic risks. Based on medians of both UACR and CRP, subjects with both higher levels of both markers had higher odds of disability and a more unfavorable metabolic profile than those with lower levels.

Conclusions: Elevated levels of CRP and UACR independently correlate with disability among older adults with CVD. There is a combined association of inflammation and albuminuria on multiple domains of disability and metabolic risks, suggesting the presence of elevated UACR may amplify the association of inflammation with disability and with metabolic risk in older adults living with CVD.