Association between urinary sodium-to-potassium ratio, elevated blood pressure phenotypes and microalbuminuria: Tehran Lipid and Glucose Study

Abstract

Abstract This cross-sectional study investigated the associations between urinary sodium (UNa) to potassium (UK) ratio, different phenotypes of elevated blood pressure (BP), and microalbuminuria (MAU) in a cohort of the Tehran Lipid and Glucose Study (TLGS). Adult participants (n = 1782, mean age of 43.0 ± 13.7 years and 46.0% were men) were recruited (2015–2017) for measurements of spot urinary metabolites, i.e., Na, K, creatinine (Cr), microalbumin, and BP. Multinomial logistic regression was used to estimate the relative risk ratios (RRR) of elevated BP phenotypes [i.e., isolated systolic (ISH), diastolic (IDH), and systolic-diastolic (SDH) hypertension], and binary logistic regression was used to estimate odds ratios (ORs) of MAU across quintile categories and per each SD-increment of UNa-K ratio. Mean UNa, UK, and its ratio was 137 ± 57.4, 72.1 ± 36.6 mmol/L, and 2.31 ± 1.41, respectively. Subjects with UNa-K > 3.14 had higher prevalence of ISH (3.4 vs. 1.1%), SDH (11.0 vs. 6.2%), and MAU (14.1 vs. 6.2%) (P for all 3.14 vs. <1.23) was associated with an increased probability of SDH (RRR = 1.79, 95% CI 1.09–3.19) and MAU (OR = 2.53, 95% CI 1.23–5.20). Every 1 SD-increment of the UNa-K ratio was associated with a 29 and 38% increased chance of having SDH and MAU, respectively. Our findings imply that a high UNa-K ratio may be a potential risk factor for elevated BP and renal dysfunction.

Keywords

• Sodium
• Potassium
• Blood pressure
• Hypertension phenotypes
• Microalbuminuria