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 m²).

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% CI, 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 (1.1%) experienced a fatal and nonfatal vascular event. Subjects with baseline Ccr less than the median (75 mL/min/1.73 m²) 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 m² 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.

Index Words: Chronic kidney disease, intima-media thickness, cardiovascular mortality