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Purpose This cross-sectional study aimed to evaluate BMD, bone microarchitecture and prevalent fractures in women with chronic hypoparathyroidism (HypoPT). Methods Twenty-seven women with HypoPT and 44 age-matched healthy women were included. Dual-energy x-rays absorptiometry (DXA) was used to evaluate areal BMD (aBMD) at the spine and hip as well as morphometric vertebral fractures (VFA). Microarchitecture and volumetric BMD (vBMD) were evaluated at distal radius and tibia using high resolution peripheral quantitative computed tomography (HR-pQCT). Biochemical parameters, including FGF23 (fibroblast growth factor 23), CTX (C- terminal telopeptide of type I collagen) and P1NP (procollagen type I N-terminal propeptide), were measured. Previous low-impact fractures were also assessed, and the 10-year fracture risk was estimated using the FRAX tool for Brazilian population. Results There was a low risk of fractures on FRAX tool in all patients, and only two had morphometric vertebral fractures: one patient presented severe VF (T5) and moderate VF (T6); another patient had moderate spinal deformity at T8. No patient had a history of previous clinical fractures. Compared to controls, HypoPT women had higher aBMD in the lumbar spine (p = 0.030), femoral neck and total hip (p < 0.001) and higher cortical vBMD (p = 0.020 in the radius and p < 0.001 in the tibia). Trabecular bone was not affected. Both bone turnover markers P1NP and CTX were compatible with low turnover in the HypoPT patients. However, we found no statistically significant correlations between BMD and any biochemical data, including serum phosphate, CTX and P1NP. Conclusions There was a low prevalence of fragility fractures, compatible with the low fracture risk estimated by FRAX, in the twenty-seven HypoPT women studied. These patients had higher areal BMD and cortical vBMD as compared to controls, but the association with decreased bone turnover was not clear. Future longitudinal studies are needed to clarify the mechanisms involved in the bone fragility described in HypoPT patients.

Introduction: Vascular calcification related to severe secondary hyperparathyroidism (SHPT) is an important cause of cardiovascular and bone complications, leading to high morbidity and mortality in patients with chronic kidney disease (CKD) undergoing hemodialysis (HD). The present study aimed to analyze whether ankle-brachial index (ABI), a non-invasive diagnostic tool, is able to predict cardiovascular outcomes in this population. Methods: We selected 88 adult patients on HD for at least 6 months, with serum iPTH>1,000pg/mL. We collected clinical data, biochemical and hormonal parameters, and ABI (sonar-Doppler). Calcification was assessed by lateral radiography of the abdomen and by simple vascular calcification score (SVCS). This cohort was monitored prospectively between 2012 and 2019 for cardiovascular outcomes (death, myocardial infarction (MI), stroke, and calciphylaxis) to estimate the accuracy of ABI in this setting. Results: The baseline values were: iPTH: 1770±689pg/mL, P: 5.8±1.2 mg/dL, corrected Ca: 9.7±0.8mg/dL, 25(OH)vit D: 25.1±10.9ng/mL. Sixty-five percent of patients had ABI>1.3 (ranging from 0.6 to 3.2); 66% had SVCS≥3, and 45% aortic calcification (Kauppila≥8). The prospective evaluation (51.6±24.0 months), provided the following cardiovascular outcomes: 11% of deaths, 17% of nonfatal MI, one stroke, and 3% of calciphylaxis. After adjustments, patients with ABI≥1.6 had 8.9-fold higher risk of cardiovascular events (p=0.035), and ABI≥1.8 had 12.2-fold higher risk of cardiovascular mortality (p=0.019). Conclusion: The presence of vascular calcifications and arterial stiffness was highly prevalent in our population. We suggest that ABI, a simple and cost-effective diagnostic tool, could be used at an outpatient basis to predict cardiovascular events in patients with severe SHPT undergoing HD.