Comparison on metabolic disorders and uric acid levels between patients with primary aldosteronism and essential hypertension

Abstract

Objective: To compare the incidence of metabolic disorders and uric acid (UA) levels between patients with primary aldosteronism (PA) and essential hypertension (EH), and to explore factors associated with UA levels in these patients. Methods: A total of 117 PA and 117 EH patients individually matched by sex, age, blood pressure and duration of hypertension were recruited from in-hospital patients who were hospitalized in our department because of suspicion of secondary hypertension from January 2008 to December 2014. Clinical data including metabolic disorders and UA levels were analyzed. Results: (1) Body mass index (BMI), waist circumference, plasma triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), free fatty acid (FFA) were significantly higher in EH than in PA group (all P<0.05). Prevalence of diabetes mellitus or impaired glucose tolerance (DM+ IGT) was significantly higher in EH than in PA group (41.9% (49/117) vs. 17.1% (20/117), P<0.01). The prevalence of metabolic syndrome (MS) was also significantly higher in EH than in PA group (51.3% (60/117) vs. 24.8% (29/117), P<0.01). (2) EH patients had higher homeostasis model assessment for insulin resistance (HOMA-IR) and lower insulin sensitivity index composite (ISI comp) than PA patients, but basic insulin secretion index (HOMA-β) and modified β cell function index (MBCI) were significantly lower in PA than in EH group (P<0.05). (3) With regard to target organs damages, PA patients revealed higher 24-hour urinary protein, urinary albumin excretion rate (UAER), urinary IgG, urinary α-1 microglobulin, left ventricular mass index and lower urine specific gravity than EH patients (all P<0.05). There was no significant difference in estimated glomerular filtration rate (eGFR) between two groups (P=0.103). (4) UA level was significantly lower in PA group than in EH group ((314.00±89.52) μmol/L vs. (379.16±101.25) μmol/L, P<0.01). Higher plasma aldosterone concentration and lower plasma renin activity were associated with lower UA level in PA group. Conclusions: Compared with sex, age and hypertension duration matched EH patients, PA patients revealed lower UA level and less severe abnormalities of glucose and lipid metabolism, but are associated with severer renal and cardiac damages. The reduced UA level in PA patients is possibly due to the high plasma aldosterone concentration and low plasma renin activity.