Abstract MP24: Urinary Potassium Excretion and Risk of Developing Hypertension

Abstract

Background: Potassium supplementation lowers blood pressure (BP) in randomized controlled trials, but the long-term effect of dietary potassium intake on risk of hypertension has not yet been established. Objective: To examine the association of 24h urinary excretions of potassium, reflecting dietary uptake, with risk of hypertension. Methods: We used data from the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study, a prospective, community-based, observational cohort of Dutch men and women aged 28-75 years. Potassium excretion was measured at baseline (1997-98) and during follow-up (2001-03) in two consecutive 24h urine specimens. Risk of hypertension (defined as BP ≥140/90 mmHg, or initiation of BP-lowering drugs) was studied in 5,511 normotensive subjects not using BP-lowering drugs at baseline. We used Cox proportional hazards regression analysis with time-dependent covariates. Results: Baseline median potassium excretion was 72 mmol/24h (Q1-Q3: 57-85 mmol/24h). During a median follow-up of 7.6 years (Q1-Q3: 5.0-9.3 years), 1172 subjects developed hypertension. We observed a nonlinear association between potassium excretion and risk of hypertension (P=0.005; Figure ). This association was in such a way that the lowest sex-specific tertile of potassium excretion (men: <68 mmol/24h; women: <58 mmol/24h) had an increased risk of hypertension (hazard ratio [HR], 1.22; 95% confidence interval [CI], 1.08-1.37) after adjustment for age and sex, compared to the upper two tertiles. Further adjustment for body mass index, smoking status, alcohol intake, parental history of hypertension (HR, 1.25; 95% CI, 1.11-1.41), and additionally for 24h urinary excretions of sodium, magnesium, and calcium (HR, 1.23; 95% CI, 1.08-1.40) did not materially affect the association. Conclusions: In this population-based cohort, low potassium excretion was associated with an increased risk of developing hypertension. Figure: Association between 24h urinary potassium excretion and risk of hypertension.