Impact of subclinical carotid atherosclerosis on incident chronic kidney disease in the elderly.

BACKGROUND: Cardiovascular disease (CVD) is increased in persons with chronic kidney disease (CKD); however, no prospective studies have examined carotid intima-media thickness (CIMT) as a risk factor for CKD.

METHODS: A total of 2751 participants who were in the Intervention Project on Cerebrovascular Diseases and Dementia in the community of Ebersberg, Bavaria study and had normal baseline kidney function composed the study cohort. Measures of kidney function were estimated glomerular filtration rate (eGFR) using the Cockcroft-Gault formula in mL/min/1.73 m(2). The main outcome measure was incident CKD defined as an eGFR < 60 mL/min/1.73 m(2) at study year 2 among those with an eGFR >or= 60 mL/min/1.73 m(2) at baseline. Multivariate Cox regression models were used to assess the association between CIMT and incident CKD.

RESULTS: In multivariate analysis, there was a significant and graded association in eGFR decline, -8 +/- 21, -10 +/- 22, -11 +/- 12 and -15 +/- 11 mL/min/1.73 m(2) for the baseline CIMT quartiles 1 (<0.66 mm), 2 (0.66-0.77 mm), 3 (0.77-0.88 mm) and 4 (>0.88 mm), respectively (P for trend: 0.01), during the 2-year follow-up period. Subjects with a baseline CIMT in the fourth quartile developed a significant decrease in eGFR as compared with subjects with a baseline CIMT in the first quartile (P < 0.01). After adjustment for confounding factors, the baseline CIMT remained a predictor for the occurrence of CKD [hazard ratio, 1.17; 95% confidence interval (CI), 1.08-1.30].

CONCLUSIONS: Increases in CIMT, as measured non-invasively by ultrasonography, are directly associated with an increased risk of CKD in elderly individuals.