Characterization of primary hyperparathyroidism based on target organ involvement: An analysis from the Indian PHPT registry.

BACKGROUND: It has been a matter of debate for long time about the existence of two distinct phenotypes of primary hyperparathyroidism (PHPT) predisposed to either renal or skeletal manifestation. OBJECTIVE: To differentiate characteristics of symptomatic PHPT patients based on the presence of skeletal or renal involvement. DESIGN: Retrospective analysis of data from the Indian PHPT registry. PATIENTS: PHPT patients were divided into four discrete groups: asymptomatic, presenting with renal manifestations alone, skeletal manifestations alone, and both skeletal and renal manifestations. MEASUREMENTS: Clinical, biochemical, and tumour weight and histopathological characteristics of these groups were compared. RESULTS: Of the 229 eligible patients, 45 were asymptomatic, 62 had renal manifestations, 55 had skeletal manifestations, and 67 had both skeletal and renal manifestations. Patients with both skeletal and renal manifestations had higher serum calcium levels than those with isolated skeletal involvement [12.5 (11.1-13.7) mg/dL, 11.2 (10.6-12.3) mg/dL, respectively; p < .05]. Serum alkaline phosphatase (AP), plasma parathyroid hormone (PTH) levels, and parathyroid tumour weight were significantly higher in patients with isolated skeletal, and both skeletal and renal manifestations, compared to the other two groups. A preoperative PTH and AP level of 300 pg/mL and 152 U/L, predicted the risk of developing skeletal involvement with sensitivity and specificity of 71%, 70%, and 69%, 67%, respectively. CONCLUSIONS: We observed distinct skeletal and renal phenotypic subgroups among PHPT patients with characteristic biochemical and hormonal patterns with higher parathyroid disease burden in patients with skeletal complications compared to those with isolated renal manifestation.

Weight gain after curative parathyroidectomy predicts increase in bone mineral density in patients with symptomatic primary hyperparathyroidism.

BACKGROUND: Primary hyperparathyroidism (PHPT) results in reduction of bone mineral density (BMD) and an increased risk of pathological fractures. Curative surgery does improve BMD; however, the magnitude of rise and predictive factors are highly variable amongst the hitherto available studies. OBJECTIVES: To quantify the magnitude of improvement in BMD after curative surgery in patients with symptomatic PHPT and dissect out the possible clinical and biochemical parameters predicting the BMD rise. METHODS: We conducted a retrospective study of symptomatic PHPT patients undergoing surgery between August 2016 and July 2018. Patients achieving biochemical cure with pre- and post-operative (at least 1 year after surgery) dual-energy X-ray absorptiometry scans performed were included in the study. RESULTS: After exclusion, 63 patients were included in the study (M:F = 2:5; mean age = 44.8 years). At a median interval of 15 months, the median per cent change in BMD (ΔBMD) at lumbar spine (LS), total hip (TH), femoral neck (FN) and one-third distal radius (forearm) was 6.5%, 7.0%, 8.1% and 6.9%, respectively. Following multiple linear regression analysis, baseline BMD was found to inversely predict ΔBMD at LS, TH and forearm. Pre-operative iPTH positively predicted ΔBMD at LS and FN. Interestingly, 82.5% of the patients had a gain in body weight following curative surgery and change in body weight emerged as a significant positive predictor of ΔBMD at all sites. CONCLUSIONS: Curative surgery improves BMD at all sites in patients with symptomatic PHPT. Weight gain following surgery can be used as a positive clinical predictor of BMD rise.