Correlation Between Parathyroid Hormone Levels with Urinary Magnesium Excretion in Patients with Non-Dialysis Dependent Chronic Kidney Disease

BACKGROUND: Disorders of mineral metabolism occur in most patients with chronic kidney disease (CKD). The aim of this work was to correlate parathyroid hormone (PTH) levels with urinary magnesium excretion in patients with non-dialysis dependent CKD. METHODS: Cross-sectional study. Concentrations of creatinine, magnesium, calcium, phosphate, parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D] and alkaline phosphatase (ALP) were determined in blood samples. The assessment of urinary magnesium levels was performed by means of total daily excretion and by the excretion fraction (FEMg). RESULTS: The study evaluated 163 patients with a mean age of 60.7 ± 11.7 years and 51.0% were male. In the highest quartile of PTH (>89.5pg/mL), the mean levels of FEMg and ALP were higher (p<0.05). In the unadjusted regression analysis, the following variables were related to serum PTH levels: FEMg (odds ratio (OR) = 1.12; 95% confidence intervals (CI): 1.02–1.23), calcium (OR = 0.45; 95% CI: 0.22–0.90), ALP (OR = 1.02; 95% CI: 1.00–1.03) and eGFR (OR = 0.92; 95% CI: 1.00–1.03). After an adjusted analysis, only one FEMg and ALP will remain correlated with PTH. CONCLUSION: In patients with non-dialysis dependent CKD, FEMg and ALP were some variables that remained associated with PTH.