Osteonecrosis of the jaws in patients assuming oral bisphosphonates for osteoporosis: a retrospective multi-hospital-based study of 87 Italian cases

BACKGROUND: Bisphosphonates (BPs) are currently the chief drugs for the prevention/treatment of osteoporosis; one of their adverse effects is the osteonecrosis of the jaw (BRONJ). The primary endpoints of this multi-center cross-sectional study are: i) an observation of the clinical features of BRONJ in 87 osteoporotic, non-cancer patients; and ii) an evaluation of their demographic variables and comorbidities. METHODS: 87 BRONJ patients in therapy for osteoporosis with BPs from 8 participating clinical Italian centers were consecutively identified and studied. After BRONJ diagnosis and staging, comorbidities and data relating to local and drug-related risk factors for BRONJ were collected. RESULTS: 77/87 (88.5%) patients in our sample used alendronate as a BP type; the duration of bisphosphonate therapy ranged from 2 to 200 months, and 51.7% of patients were in treatment for ≤ 38 months (median value). No comorbidities or local risk factors were observed in 17 (19.5%) patients, indicating the absence of cases belonging to BRONJ forms triggered by surgery. BRONJ localization was significantly associated with age: an increased risk of mandible localization (p=0.002; OR=6.36, 95%CI=[1.89; 21.54]) was observed for those over 72 yrs. At multivariate analysis, the increased risk of BRONJ in the mandible for people over 72 yrs (OR'=6.87, 95%CI=[2.13; 2.21]) was confirmed for a BP administration >56 months (OR'=4.82, 95%CI=[2.13; 22.21]). CONCLUSION: Our study confirms the fundamental necessity of applying protocols of prevention in order to reduce the incidence of BRONJ in osteoporotic, non-cancer patients in the presence of comorbidities and/or local risk factor as well as, less frequently, in their absence