Current guidelines recommend low dietary salt intake in patients with diabetes to reduce blood pressure. However, low salt intake has been associated with higher mortality rates in people with diabetes. Our aim is to examine the effect of angiotensin II receptor blocker (ARB), telmisartan, with and without dietary sodium chloride (NaCl) supplementation, on blood pressure (mean arterial pressure, MAP), plasma renin activity (PRA), serum aldosterone level and estimated glomerular filtration rate (eGFR) in hypertensive patients with type 2 diabetes. In a randomised, double blind, controlled study (RCT), 28 patients with type 2 diabetes, treated with telmisartan (40mg daily), received two weeks of placebo or NaCl capsules (100mmol/24h). Following a six-week washout, the protocol was repeated in reverse. Twenty-four hour urinary sodium excretion (24hUNa), ambulatory blood pressure monitoring and blood tests were performed before and after each study phase. The telmisartan associated increase in PRA was blunted by approximately 50% during salt supplementation compared with placebo; median PRA was 2.3 ug/l/hr with placebo vs 1.7ug/l/hr with salt (p<0.001). A trend towards blunting of ARB induced increases of serum aldosterone was also demonstrated. Salt supplementation significantly reduced the MAP lowering effects of telmisartan (p<0.05). This study demonstrates that salt supplementation blunts the telmisartan induced increase in PRA in patients with type 2 diabetes.
- Copyright 2015 The Author(s)
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