PURPOSE: To quantify the incidence of osteonecrosis of the jaw (ONJ) by bisphosphonate exposure among two cohorts of patients.
METHODS: In a retrospective cohort study, we identified cohort members via health insurance claim diagnosis codes and identified potential cases of ONJ that were confirmed with medical record review. One cohort included patients aged ≥40 years with breast or prostate cancer or multiple myeloma; the other cohort included men aged ≥60 years and women ≥50 years with osteoporosis. For each cohort, we calculated sex- and age-standardized incidence of ONJ by exposure to oral bisphosphonates and intravenous bisphosphonates.
RESULTS: In the cancer cohort (n = 46 542), sex- and age-standardized incidence of ONJ (n = 26 probable or possible cases) adjusted for abstraction proportion was 0.29 per 1000 person-years (95% confidence interval [CI], 0.07-0.52) among those unexposed to bisphosphonates and 5.3 (95%CI, 1.9-8.7) after intravenous bisphosphonate use. Controlling for covariates, the rate ratio for intravenous use versus no use was 8.8 (95%CI, 2.0-38). Patients with multiple myeloma had a rate 4.5 times that of patients with breast cancer. In the osteoporosis cohort (n = 31 244), sex- and age-standardized ONJ (n = 11 probable or possible cases) incidence was 0.26 per 1000 person-years (95%CI, 0.06-0.47) among those unexposed to bisphosphonate and 0.15 (95%CI, 0.00-0.36) after oral bisphosphonate use.
CONCLUSION: Among patients with selected cancers, incidence of ONJ was higher among those with multiple myeloma and users of intravenous bisphosphonates.
