Bone Microstructure and Bone Strength Among Patients with Pseudohypoparathyroidism

The present study aimed to assess bone strength and microstructure in patients with pseudohypoparathyroidism (PHP), nonsurgical HP (NS-HP), and healthy controls. A total of 54 PHP1 patients (14 PHP1a, 40 PHP1b), 54 age-/sex- matched NS-HP patients and 27 age-/sex-matched controls were enrolled. Clinical characteristics, biochemical indices and HR-pQCT indices were respectively collected. PHP1 patients had higher serum Ca and PTH level than NS-HP patients at the time of both diagnosis and HR-pQCT measurement. A higher BMI and lower serum P level were observed in PHP1 patients than NS-HP patients at the time of HR-pQCT measurement. Bone microstructure analysis showed PHP1 patients had decreased Tb.N, increased Tb.Sp, and increased Tb.1/N.SD at tibia compared to NS-HP patients. Subgroup analysis showed no significant difference in Tb.N and Tb.Sp in PHP1b patients compared to NS-HP patients. Multiple linear regression analysis showed increased Tb.N and decreased Tb.Sp at tibia were associated with longer treatment duration in PHP1b patients. The microarchitecture evaluated by HR-pQCT in this study further supported that bone tissue had a preserved sensitivity to PTH in PHP1 patients and trabecular bone was more susceptible. Moreover, at least, bone status in PHP1b patients might benefit from regular treatment.