BACKGROUND:The association between bone turnover, measured by C-terminal telopeptide (CTX), and medication-related osteonecrosis of the jaw (MRONJ) following dental extraction in denosumab-treated osteoporosis patients is not well characterized. PURPOSE:To evaluate the association between preoperative CTX and time to MRONJ development following dental extraction in patients receiving denosumab for osteoporosis. STUDY DESIGN, SETTING, SAMPLE:A prospective cohort study was conducted at a tertiary oral and maxillofacial surgery center in Australia (2017 to 2023). Patients receiving denosumab 60 mg for osteoporosis who underwent dental extraction with preoperative fasting CTX measurement were included. Patients with metastatic disease, metabolic bone disorders, prior head and neck radiotherapy, or current bisphosphonate therapy were excluded. PREDICTOR VARIABLE:Bone turnover measured using preoperative fasting serum CTX level relative to 150 ng/L and the cohort mean. MAIN OUTCOME VARIABLE:Time to MRONJ following dental extraction. COVARIATES:Age, sex, comorbidity status, number of teeth extracted, and timing of CTX relative to the last denosumab dose. ANALYSES:Group comparisons used χ2 and Student's t-tests. Time-to-event analysis used Kaplan-Meier estimates and Cox proportional hazards regression (P < .05). RESULTS:Of 1,020 eligible subjects, the sample was composed of 314 (31%) subjects with mean age of 76.2 ± 8.7 years and 253 (81%) were female. MRONJ developed in 9 subjects (2.9%), with an incidence of 0.056 per person-year of follow up (95% CI, 0.029 to 0.108) and median time to diagnosis of 6.6 months (interquartile range, 3.6 to 9.0). Mean CTX was 216.6 ng/L, and 210 subjects (67%) were below this level, including 7 of 9 MRONJ cases. In univariate Cox regression, each unit increase in CTX was associated with a 0.81% reduced MRONJ risk (hazard ratio, 0.99; 95% CI, 0.98 to 1.00; P = .045), and each additional tooth extracted was associated with a 24.8% increase in MRONJ risk (hazard ratio, 1.25; 95% CI, 1.02 to 1.53; P = .031). CONCLUSION AND RELEVANCE:Lower CTX levels and greater number of extractions were associated with increased risk for developing MRONJ among patients with osteoporosis treated with denosumab who require dental extractions.
