EFFECTS OF ORAL POTASSIUM ON BLOOD-PRESSURE - METAANALYSIS OF RANDOMIZED CONTROLLED CLINICAL-TRIALS

Objective.-To assess the effects of supplementation with oral potassiu m on blood pressure in humans. Design.-Meta-analysis of randomized con trolled trials. Data Sources.-English-language articles published befo re July 1995. Study Selection.-Thirty-three randomized controlled tria ls (2609 participants) in which potassium supplementation was the only difference between the intervention and control conditions. Data Extr action.-Using a standardized protocol, 2 of us independently abstracte d information on sample size, duration, study design, potassium dose, participant characteristics, and treatment results. Results.-By means of a random-effects model, findings from individual trials were pooled , after results for each trial were weighted by the inverse of its var iance. An extreme effect of potassium in lowering blood pressure was n oted in 1 trial. After exclusion of this trial, potassium supplementat ion was associated with a significant reduction in mean (95% confidenc e interval) systolic and diastolic blood pressure of -3.11 mm Hg (-1.9 1 to -4.31 mm Hg) and -1.97 mm Hg (-0.52 to -3.42 mm Hg), respectively . Effects of treatment appeared to be enhanced in studies in which par ticipants were concurrently exposed to a high intake of sodium. Conclu sions.-Our results support the premise that low potassium intake may p lay an important role in the genesis of high blood pressure. Increased potassium intake should be considered as a recommendation for prevent ion and treatment of hypertension, especially in those who are unable to reduce their intake of sodium.