Supplementary Material for: Association between the use of calcimimetics and vitamin D receptor activators and fracture risk in patients undergoing maintenance hemodialysis: a cohort study

Introduction
Secondary hyperparathyroidism is a major complication of maintenance hemodialysis (MHD). Elevated serum parathyroid hormone levels increase fracture risk. We aimed to investigate the association between secondary hyperparathyroidism medication and fracture risk in patients undergoing MHD.
Methods
Patient data from a large medical claims database were used. Patients receiving MHD were divided into untreated, vitamin D receptor activator (VDRA), and calcimimetic groups. The outcome was the first hospitalization due to any fracture. First hospitalization for hip or vertebral fracture was evaluated. Hazard ratios (HRs) were assessed using a weighted Cox proportional hazards model with overlap weights.
Results
A total of 13,238, 4,847, and 5,977 patients comprised the untreated, VDRA, and calcimimetic groups, respectively. The untreated and calcimimetic groups showed a slightly lower incidence risk of any fracture than the VDRA group, although no significant difference was observed (HR, 0.85; 95% confidence interval [CI], 0.66–1.10 and HR, 0.84; 95% CI, 0.64–1.09, for the untreated and calcimimetic groups, respectively). Regarding hip fracture, the calcimimetic group exhibited a similar downward trend compared with any fracture, whereas the untreated group showed an incidence risk comparable with that of the VDRA group (HR, 0.91; 95% CI, 0.62–1.33 and HR, 0.77; 95% CI, 0.50–1.18, for the untreated and calcimimetic groups, respectively). The risk of vertebral fracture showed a downward trend in both groups, with the calcimimetic group exhibiting a significantly lower risk (HR, 0.63; 95% CI, 0.36–1.10 and HR, 0.45; 95% CI, 0.23–0.86, for the untreated and calcimimetic groups, respectively).
Conclusion
Calcimimetic use may reduce fracture incidence in patients undergoing MHD more effectively than VDRA.