A new marker of carotid atherosclerosis in middle aged adults: cystatin C or microalbuminuria.

OBJECTIVE: Cystatin C and microalbuminuria, the new markers of atherosclerosis, have been shown to predict cardiovascular outcome in older individuals. However there is limited data regarding their role in middle aged individuals with preserved renal functions. Hence this study. METHODS: Patients aged 45 to 65 years irrespective of presence or absence of diabetes, hypertension or coronary artery disease were subjected to high resolution B mode ultrasonography for carotid artery intimal-medial complex thickness (IMT). Patients with maximal intimal-medial complex thickness greater than 800 microm at the far wall of the common carotid artery, excluding raised lesions and plaques, were selected for the study. Study participants were subjected to biochemical tests for serum cystatin-C, serum creatinine, glomerular filtration rate (GFR) and for presence of microalbuminuria. The relationship of carotid artery intimal-medial complex thickness with serum cystatin C and microalbuminuria was compared. RESULTS: The mean carotid IMT of the study group was 928 +/- 117 microm. Carotid IMT was significantly associated with advancing age, raised systolic blood pressure, ESR, GFR, LDL cholesterol and microalbuminuria but not with cystatin C. Carotid IMT has significant association with systolic blood pressure but not with diastolic blood pressure. There was a statistically significant difference in ESR across tertiles (p < 0.05). There was a statistically significant difference in GFR across tertiles (p < 0.05) and an inverse relationship was found between GFR and IMT. Carotid IMT was positively and significantly correlated with microalbuminuria but there was no significant correlation of carotid IMT with serum cystatin C. CONCLUSION: Microalbuminuria was found to be associated with carotid atherosclerosis in middle aged individuals. However cystatin C was not associated with carotid atherosclerosis in patients with preserved renal functions.