Comparison of Calcium, Vitamin D and PTH in Different Subgroups of Steroid Sensitive Nephrotic Syndrome

Abstract

Background: Steroid-sensitive nephrotic syndrome (SSNS) is frequently associated with alteration of calcium and vitamin D metabolism, including hypocalcemia, reduced serum vitamin D metabolites, and elevated levels of parathyroid hormone (PTH). These alterations occur usually due to intestinal malabsorption of calcium as well as excessive urinary losses of various vitamin D metabolites and their binding proteins which, in turn, lead to a decrease in bone mineral density. So, early identification and management of the abnormal levels of calcium, vitamin D, and PTH can ameliorate growth retardation. Objective: Our aim is to compare the level of calcium, vitamin D, and PTH in different subgroups of SSNS. Materials and Methods: This cross-sectional study was carried out in the Department of Paediatric Nephrology, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh, from January 2018 to June 2019. A total of 45 patients with previously diagnosed SSNS, aged 2–18 years of both sexes, were included in this study. The children were divided into three groups of 15 each. Group I comprised of 15 patients who presented with infrequent relapse nephrotic syndrome(IRNS), Group II comprised 15 patients who hadfrequent relapse nephrotic syndrome or steroid dependent nephrotic syndrome (FRNS/SDNS), and Group III comprised of 15 patients who were in remission for last 3 months without any medication. Then serum calcium, vitamin D, and PTH levels were compared among the study population. Results: A total of 45 patients were studied. Serum calcium was significantly lower in groups I and II compared to group III (P < 0.05). Mean serum PTH levels were 34.02 ± 15.33, 50.52 ± 19.22, and 40.33 ± 14.58 pg/mL in groups I, II, and III, respectively. Among the study group, vitamin D levels were deficient in 26 (58%), insufficient in 14 (31%), and sufficient in 5 (11%) children. Among the subgroups, mean serum vitamin D levels were 8.98 ± 1.96 ng/mL in patients with IRNS, 4.27 ± 1.37 ng/mL in FRNS/SDNS group, and 18.49 ± 7.34 ng/mL in patients who were in remission for more than 3 months. Serum vitamin D levels were low in groups I and II compared to group III, with statistically significance (P < 0.001). Conclusion: This study finding concluded that mean serum vitamin D levels were low in all the subgroups of SSNS children which were statistically significant. Specifically, all children with frequent relapse and steroid dependent nephrotic syndrome were vitamin D deficient.