Effects of Intensive Low-Salt Diet Education on Albuminuria among Nondiabetic Patients with Hypertension Treated with Olmesartan: A Single-Blinded Randomized, Controlled Trial

Abstract

Background and objectives The antiproteinuric effect of a renin-angiotensin-aldosterone system blockade can be magnified by dietary salt restriction. This study sought to determine the effect of intensive low-salt diet education on BP and urine albumin excretion in nondiabetic patients with hypertension and albuminuria. Design, setting, participants, & measurements This study was conducted between March of 2012 and March of 2013 as an open-label, randomized, controlled trial. After a run-in period of 8 weeks, all patients received the angiotensin II receptor blocker olmesartan (40 mg daily). Patients were then divided into two groups. One group was treated for another 8 weeks with angiotensin II receptor blocker plus conventional low-salt diet education, and the other group was treated for 8 weeks with angiotensin II receptor blocker plus intensive low-salt diet education. The final analyses was performed with 245 completed patients. Results The amount of daily albuminuria was significantly decreased from 0 (566.0 [25.0-5398.6] mg/d) to 8 weeks (282.5 [16.1-4898.5] mg/d; P<0.001). From 8 to 16 weeks, the 24-hour urinary sodium excretion was decreased by 36.0 +/- 5.9 mmol/d in the intensive education group and 8.8 +/- 4.9 mmol/d in the conventional education group (interaction P<0.001). Patients who completed intensive low-salt diet education exhibited greater decreases in urinary albumin excretion than the control group (change in albuminuria from 8 to 16 weeks, -154.0 versus 0.4 mg/ d; P=0.01). Urinary albumin excretion tended to decrease as the 24-hour urinary sodium excretion amount decreased (R=0.32; 95% confidence interval, 0.20 to 0.43; P<0.001). Conclusions The 24-hour urinary albumin excretion was decreased more in patients in the intensive low-salt diet education group than patients in the conventional education group. Weekly intensive education on a low-salt diet would be a suitable method for clinical practice.