Kidney function and progression of carotid intima-media thickness in a community study

Background: Limited data exist regarding the relationship between decreased kidney function, carotid intima-media thickness (IMT) progression, and vascular events. Study Design: A community-based cohort study. Setting & Participants: 3,364 participants in the Intervention Project on Cerebrovascular Diseases and Dementia in the Community of Ebersberg, Bavaria Study. Predictor: Quartiles of kidney function level estimated by means of creatinine clearance (Ccr) using the Cockcroft-Gault equation (Ccr < 64, 64 to 75, 75 to 89, and > 89 mL/min/1.73 m(2)). Outcomes & Measurements: Change in carotid IMT during 2 years. Composite clinical study end point is the occurrence of major adverse cardiovascular events, a composite of myocardial infarction, stroke, and vascular death after 2 years. Results: Baseline mean carotid IMT was 0.79 +/- 0.19 (SD) mm. Mean change in carotid IMT was 0.02 +/- 0.11 mm/y. Lower Ccr quartile at baseline was associated with a greater change in adjusted mean values: 0.024 (95% confidence interval [CI], 0.020 to 0.027); 0.019 (95% Cl, 0.015 to 0.023); 0.012 (95% CI, 0.009 to 0.016); and 0.0077 (95% CI, 0.005 to 0.011), respectively (P < 0.01). After evaluation of change in carotid IMT, 36 patients (11.1%) experienced a fatal and nonfatal vascular event. Subjects with baseline Ccr less than the median (75 mL/min/1.73 m(2)) and change in carotid IMT greater than the median (0.008 mm/y) had the worst prognosis (log-rank test, P = 0.04). By means of multivariable analysis with the Cox proportional hazard model, lower baseline Ccr (hazard ratio, 1.04; 95% CI, 1.02 to 1.23; P = 0.03 per 1-mL/min/1.73 m(2) decrease) and faster change in carotid IMT (hazard ratio, 1.15; 95% CI, 1.11 to 1.93; P= 0.01 per 0.1-mm increase) were associated with fatal and nonfatal vascular events. Limitations: Microalbuminuria, associated with carotid atherosclerosis, was not available. Conclusion: Decreased kidney function is associated strongly with faster change in carotid IMT. In addition, decreased kidney function and faster change in carotid IMT are associated with cardiovascular events.