Relationship between parathyroid hormone and electrolytes in chronic kidney disease

Abstract

Parathyroid hormone (PTH) has been identified as the main regulator of some electrolytes homeostasis. This study evaluated the relationship between PTH and these electrolytes as well as their ratios. The study population included 146 individuals with mean age of 50.18 ± 1.14 with various chronic kidney diseases and who were undialysed. 80 healthy subjects without kidney pathology but of similar age and sex distribution were used as controls. Estimated glomerular filtration rate (eGFR) was calculated using the 4v-MDRD and CKD was defined as eGFR <60 ml/min/1.73 m2. For every mmol/l increase in the serum concentration of phosphate (PO43-) (r2 = 0.78, p < 0.0001), potassium (K+) (r2 = 0.00366, p < 0.0211) and magnesium (Mg2+) (r2 = 0.2861, p < 0.0001) there was a corresponding increase in serum concentration of PTH with beta values of 0.005, 0.0007, 0.001 + 2 respectively. However, there was no linear relationship between sodium (Na ) and PTH (r = 0.0013, p = 0.6687). The serum concentration of PTH decreased, for every mmol/l increase in the serum concentrations of calcium (Ca2+) (r2 = 0.33, p < 0.0001). Excess PTH is linked with derangements in the metabolism of electrolytes like calcium, magnesium, phosphorus and potassium in subjects presenting with CKD and contributes to a plethora of complications.