Prevalences of hyperuricemia and electrolyte abnormalities in patients with chronic kidney disease in Japan: A nationwide, cross-sectional cohort study using data from the Japan Chronic Kidney Disease Database (J-CKD-DB)

Abstract

Background: The Japan Chronic Kidney Disease Database (J-CKD-DB) is a nationwide clinical database of patients with chronic kidney disease (CKD) based on electronic health records. The objective of this study was to assess the prevalences of hyperuricemia and electrolyte abnormalities in Japanese patients with CKD.

Methods: In total, 35,508 adult outpatients with estimated glomerular filtration rates of 5-60 ml/min/1.73 m2 in seven university hospitals were included this analysis. The proportions of patients with CKD stages G3b, G4, and G5 were 23.5%, 7.6%, and 3.1%, respectively.

Results: Logistic regression analysis showed that prevalence of hyperuricemia was associated with CKD stages G3b (adjusted odds ratio [95% confidence interval]: 2.12 [1.90-2.37]), G4 (4.57 [3.92-5.32]), and G5 (2.25 [1.80-2.80]). The respective prevalences of hyponatremia, hypercalcemia, hyperphosphatemia, and narrower difference between serum sodium and chloride concentrations were elevated in patients with CKD stages G3b, G4, and G5, compared with those prevalences in patients with CKD stage G3a. The prevalences of hyperkalemia were 8.3% and 11.6% in patients with CKD stages G4 and G5, respectively. In patients with CKD stage G5, the proportions of patients with optimal ranges of serum uric acid, potassium, corrected calcium, and phosphate were 49.6%, 73.5%, 81.9%, and 56.1%, respectively.

Conclusions: We determined the prevalences of hyperuricemia and electrolyte abnormalities in Japanese patients with CKD using data from a nationwide cohort study.

Fig 1. Mean serum uric acid level according to eGFR5 category.

(a) All participants; (b) Men and women shown separately. Abbreviation: eGFR, estimated glomerular filtration rate. *, p<0.05.

Fig 2. Serum uric acid distribution according to G category.

(a) All participants; (b) Men; and (c) Women.

Fig 3. Mean serum electrolyte levels according to eGFR5 category.

(a) Serum sodium level; (b) Serum potassium level; (c) Serum chloride level; (d) Serum Na–Cl level; (e) Serum corrected calcium level; and (f) Serum phosphate level. Abbreviations: Serum Na-Cl level, difference between serum sodium and chloride concentrations; eGFR, estimated glomerular filtration rate.

Fig 4. Serum electrolyte distribution according to G category.

(a) Serum sodium distribution (%); (b) Serum potassium distribution (%); (c) Serum chloride distribution (%); (d) Serum Na–Cl distribution (%); (e) Serum corrected calcium distribution (%); and (f) Serum phosphate distribution (%). Abbreviations: Serum Na-Cl level, difference between serum sodium and chloride concentrations; C-calcium, corrected calcium.