Plasma renin activity and metabolic risk factors in essential hypertension

Abstract

Elevated plasma renin activity (PRA) has been shown to be associated with enhanced cardiovascular morbidity. In small series of patients (pts), high PRA levels have been observed in subjects with clustering of classical risk factors. Aim of the present study was to investigate the relationshipS between PRA and plasma lipids, glucose (G), insulin (I) and uric acid (UA) in a population of essential hypertensives (EH). Records of 487 EH, either untreated or whose treatment with diuretics, betablockers or ACE-inhibitors had been withdrawn at least 4 weeks before, were reviewed for baseline PRA, total, LDL- and HDL-cholesterol, triglycerides, serum G and UA and plasma I. All pts were on controlled Na intake; they were grouped according to quartiles of PRA (ngAI/ml/h)(I quart., median 0.15, range 0.05-0.25; II quart., median 0.40, range 0.30-0.60; III quart., median 0.90, range 0.65-1.30; IV quart., median 2.1, range 1.35-6.75). Sex distribution, body mass index (BMI), systolic and diastolic blood pressure values and 24-hour urinary Na were similar across quartiles of PRA. The pts in the highest quartile were slightly but significantly younger than those in the lowest quartile (46±11 vs 53±11, P<0.01). There were no significant differences in plasma lipids and serum G, whereas plasma I was highest in the highest quartile (Table). HOMA-IR, an index of insulin resistance, was also significantly higher in the IV compared with the I quartile (2.50±2.12 vs 2.05±1.35, P=0.016), even after correction for age and BMI. Serum UA was also significantly higher in the highest compared with the lowest PRA quartile. We conclude that in middle-aged, nondiabetic EH moderately elevated PRA levels are not associated with an unfavourable plasma lipid pattern; however, insulin resistance and UA levels appear to increase with increasing PRA values.