Cystatin C and cardiac hypertrophy in primary hypertension

INTRODUCTION: Cystatin C is a marker of kidney function and a predictor of cardiovascular morbidity and mortality. It is unknown whether this protein may be related to the cardiac involvement that is common among patients with essential hypertension. PATIENTS AND METHODS: We evaluated the relationship between serum cystatin C, serum creatinine, estimated glomerular filtration rate and cardiac structure assessed by echocardiography, in a group of 49 non-diabetic patients with primary hypertension and normal serum creatinine. RESULTS: Mean cystatin C levels were 0.74 +/- 0.15 mg/l. Age, body mass index, triglycerides and creatinine, estimated glomerular filtration rate and left ventricular mass index were independently associated with cystatin C levels. Seventy three per cent of patients had cardiac hypertrophy. The prevalence of left ventricular hypertrophy was higher in patients who had cystatin C levels above the 70th percentile (0.79 mg/dl) than patients below this percentile (93.3% vs 66.7%, respectively, p = 0.04). Serum cystatin C (beta = 0.48, p = 0.009), but not serum creatinine nor estimated glomerular filtration rate, was independently related to left ventricular mass index in a logistic regression analysis. CONCLUSION: Cystatin C is closely related to left ventricular mass in hypertensive patients, and could be a marker for cardiac hypertrophy in these patients.