Prevalence and risk factors for postrenal transplant hyperparathyroidism: A cross-sectional study

Abstract

Introduction: Chronic kidney disease (CKD) commonly results in secondary hyperparathyroidism. Even after a successful renal transplant, residual parathyroid overactivity persists. We studied its prevalence and risk factors in Indian patients. Patients and Methods: Patients who underwent renal transplantation in our unit from 2013 to 2019 and completed 3 months of the posttransplant period were included. We excluded patients with advanced allograft dysfunction and those on medications with the potential impact of divalent cations. A detailed history, physical examination, and laboratory parameters were obtained. Results: There were 110 subjects, of whom 78% were male. The mean age group was 38 ± 12 years. Chronic glomerulonephritis was the most common etiology of CKD (54%). Posttransplant vintage was 48 ± 44 months. The mean serum parathyroid hormone (PTH) level was 135 ± 176 pg/ml. Sixty-seven percent of them had raised serum PTH levels above 70 pg/ml. The patients were asymptomatic. Hypercalcemia and hypophosphatemia were rare. The mean 25 OH Vitamin D levels were low (23 ± 8 ng/ml) with 41% of the subjects showing either deficiency or insufficiency. Higher serum PTH levels were significantly associated with female sex, lower estimated glomerular filtration rate, and lower serum 25 OH Vitamin D levels. Serum parathormone levels were significantly negatively correlated with serum calcium (r2 = −0.39. P = 0.0003) and Vitamin D levels (r2 = −0.50. P = 0.002). Conclusions: Posttransplant hyperparathyroidism (PTHP) persists even after many years of normal allograft function. Hypercalcemia and hypophosphatemia are insensitive tests to identify the condition. Vitamin D deficiency has a strong correlation with PTHP.

Keywords

• calcium
• phosphorus
• parathyroid hormone
• renal transplantation
• vitamin d