Supplementary Material for: Association between hypokalemia and albuminuria in a Japanese general population

Introduction: Hypokalemia is associated with an increased risk of chronic kidney disease (CKD) and is a risk factor for mortality. Albuminuria is an early manifestation of CKD. We investigated the association between hypokalemia and the prevalence of albuminuria in a Japanese general population.
Methods: We analyzed the data of 18,289 subjects who underwent annual health checkups in 2018. We categorized them into four groups according to their concentration of serum potassium (sK), and performed a multivariate logistic regression analysis to determine the association between hypokalemia and the prevalence of albuminuria in this population. Hypokalemia was defined as sK = 3.1–3.5 mEq/L. After dividing the subjects into those with/without renal dysfunction, those with/without hypertension, and those with/without hyperglycemia, we examined the association between hypokalemia and albuminuria in each group.
Results: Compared to the subjects with sK = 4.1–4.5 mEq/L, the subjects with hypokalemia had a significantly high prevalence of albuminuria: multivariable-adjusted odds ratio (OR) = 2.70 (95% confidence interval (CI) 1.84–3.96). The subgroup analyses showed the following multivariable-adjusted ORs (95% CIs) of the subjects: without renal dysfunction, 3.08 (2.00–4.73); with renal dysfunction, 2.05 (0.89–4.69); without hypertension, 2.89 (1.36–6.16); with hypertension, 2.60 (1.67–4.04); without hyperglycemia, 2.49 (1.62–3.84); and with hyperglycemia, 3.55 (1.43–8.79).
Conclusions: Hypokalemia was significantly associated with the high prevalence of albuminuria in general population. Regardless of the presence/absence of renal dysfunction, hypertension, or hyperglycemia, hypokalemia was positively associated with the prevalence of albuminuria, and the associations were significant except for the subjects with renal dysfunction.