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.