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

ABSTRACT

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 (MF = 25; 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.