Association between urinary salt excretion and albuminuria in Japanese patients with chronic kidney disease: the Fukuoka kidney disease registry study

Current antihypertensive treatment and treatment-resistant hypertension in Japanese patients with chronic kidney disease

BACKGROUND

Hypertension is an important prognostic predictor in patients with chronic kidney disease (CKD), and the recommended target blood pressure has been continuously revised. This study aimed to reveal the current antihypertensive practices in Japanese patients with CKD.

METHODS

In the Fukuoka Kidney disease Registry, we extracted 3664 non-dialysis-dependent patients with CKD. Apparent treatment-resistant hypertension (aTRH) was defined as a failure of blood-pressure control treated with three antihypertensive medication classes or a treatment with ≥ 4 classes regardless of blood pressure. The blood-pressure control complied with the target blood pressure recommended by the KDIGO 2012 guideline.

RESULTS

The median age of the patients was 67 years, body mass index (BMI) was 23 kg/m², and estimated glomerular filtration rate (eGFR) was 40 mL/min/1.73 m². The number of patients with unachieved blood-pressure control was 1933, of whom 26% received ≥ 3 classes of antihypertensive medications. The first choice of medication was renin-angiotensin system inhibitors, followed by calcium-channel blockers. The rate of thiazide use was low in all CKD stages (3-11%). The prevalence of aTRH was 16%, which was significantly associated with BMI (odds ratio [95% confidence interval] per 1-standard deviation change, 1.38 [1.25-1.53]), decreased eGFR (1.87 [1.57-2.23]), as well as age, diabetes mellitus, and chronic heart disease.

CONCLUSIONS

Renal dysfunction and obesity are important risk factors of aTRH. Even under nephrologist care, most patients were treated with insufficient antihypertensive medications. It is important to prescribe sufficient classes of antihypertensive medications, including diuretics, and to improve patients' lifestyle habits.

Association between the urinary sodium-to-potassium ratio and renal outcomes in patients with chronic kidney disease: a prospective cohort study

A higher urinary sodium-to-potassium (UNa/K) ratio has been reported to be associated with high blood pressure and subsequent cardiovascular events. However, the association between the UNa/K ratio and renal outcomes remains uncertain. We prospectively investigated the association between the UNa/K ratio and renal outcomes in patients with chronic kidney disease (CKD). We enrolled 716 patients with CKD, and 24-h urinary sodium and potassium excretion were measured. Patients were divided into UNa/K ratio tertiles (T1-T3). Endpoints were defined as a composite of doubling of serum creatinine (SCr), end-stage kidney disease (ESKD), or death and a composite of doubling of SCr or ESKD (added as an alternative outcome). We investigated the association between the UNa/K ratio and renal outcomes using a Cox proportional hazards model. During a median follow-up of 2.3 years, doubling of SCr, ESKD, or death and doubling of SCr or ESKD occurred in 332 and 293 patients, respectively. After adjustment for covariates including potentially confounding variables such as plasma renin activity, plasma aldosterone concentration, and B-type natriuretic peptide, the hazard ratios (HRs) (95% confidence intervals [CIs]) for the composite of doubling of SCr, ESKD, or death for T2 and T3 were 1.44 (1.06-1.96) and 1.59 (1.14-2.21), respectively, compared with T1. Additionally, compared with T1, the highest tertile (T3) of the UNa/K ratio was associated with a composite of doubling of SCr or ESKD (HR 1.55, 95% CI 1.09-2.20). A higher UNa/K ratio was independently associated with poor renal outcomes in patients with CKD.