Sex-specific cardiovascular risk of lower potassium intake in patients with CKD

BACKGROUND: Lower potassium intake is associated with an increased risk of cardiovascular disease (CVD) in the general population, with observed sex differences. However, few studies have investigated the relationship between potassium intake and CVD in patients with chronic kidney disease (CKD), and sex-specific differences have not been well examined. METHODS: A total of 4,314 patients aged 18 years or older in Japan were prospectively followed for 5 years using data from the Fukuoka Kidney disease Registry study. The patients were divided into sex-specific quartiles according to the estimated potassium intake, which was calculated using the Tanaka formula from spot urine samples. The primary outcome was the occurrence of CVD events. Cox proportional hazards models were used to evaluate the association between the estimated potassium intake and CVD in the overall cohort with stratification by sex. RESULTS: Over a 5-year follow-up, 431 patients developed CVD (292 [12.1%] men and 139 [7.3%] women). In the overall cohort, patients in the lowest quartile of estimated potassium intake tended to have a higher hazard ratio (HR) for CVD than those in the highest quartile (HR [95% CI], 1.41 [0.97-2.03]). A significant interaction between sex and potassium intake was observed (p<0.001). In sex-stratified analyses, lower potassium intake was significantly associated with an increased risk of CVD in women (HR [95% CI]: men, 0.98 [0.63-1.53]; women, 2.97 [1.44-6.10]). CONCLUSIONS: Lower estimated potassium intake is associated with a higher risk of CVD in patients with CKD, with a particularly strong association in women.