Glomerular filtration rate and blood pressure are unchanged by increased sodium intake in atorvastatin‐treated healthy men

Abstract

Objective. Improved cardiovascular survival during statin treatment might be due to effects in addition to cholesterol lowering. We hypothesize that sodium intake affects renal function and vasoactive hormones in atorvastatin‐treated healthy subjects. Methods. In a randomized, placebo‐controlled, double‐blind, crossover study we measured the effect of a moderate change in sodium intake on glomerular filtration rate (GFR), blood pressure (BP), renal tubular function, plasma concentrations of vasoactive hormones and urinary excretion of aquaporin‐2 (u‐AQP2) in 22 healthy subjects. The subjects were randomized to standardized fluid intake and diet corresponding to the need for calories in the 4 days before each of the 2 examination days. In one of the periods they were randomized to receive sodium chloride tablets (2 g) thrice daily for 4 days. Two doses of atorvastatin (80 mg) were given; one at 2200 h the evening before the study day, the other at 0830 h in the morning. Results. 24‐h urinary sodium excretion increased by 23 %. GFR and BP were unchanged. Sodium clearance, fractional excretion of sodium and u‐AQP2 increased, whereas free water clearance decreased during high sodium intake. PRC and aldosterone were suppressed during the high sodium diet. Conclusions. A change in dietary sodium intake of approximately 100 mmol daily does not change GFR and BP in atorvastatin‐treated healthy men. The lack of change in BP might reflect that the subjects studied were not sodium sensitive, or that atorvastatin treatment modified sodium sensitivity.Trial registration: ClinicalTrials.gov identifier: NCT00678184.