Introduction: BONJ is a recognised complication of bisphosphonate treatment (both oral and intravenous). Data are sparse with the reported incidence of BONJ in the oral treatment of osteoporosis between 0.01% to 0.067% or alternatively described as 1.04 to 69 per 100,000 patient-years. This study aimed to estimate the incidence of BONJ in patients taking oral bisphosphonates as a treatment for osteoporosis.
Methods: Forth Valley Health Board (GP Practice population 317,641, Forth Valley Health Board data, 1/10/16) has one treatment centre for BONJ at Forth Valley Royal Hospital. From September 2015 to September 2016 all cases of BONJ were recorded. Data on prescriptions for bisphosphonates dispensed in the community were extracted from NHS Scotlands Prescribing Information System for the period September 2015 to September 2016 inclusive.
Results: In 201516, 4978 individuals in Forth Valley had oral bisphosphonate prescriptions dispensed in the community. In 201516 there were 8 cases of BONJ. 3 cases were receiving intravenous bisphosphonates (cancer therapy) and were excluded. 5 individuals, with post code addresses in Forth Valley, were taking oral bisphosphonates for osteoporosis treatment (4 female, 1 male, age range 5190 years with a median of 84 years, average 73 years). They were receiving oral alendronic acid (70 mg weekly) with a range of elapsed treatment time to BONJ of 29 to 117 months (median 47, average 60.2). Tooth extraction appeared to be the precipitating factor in 4 of the 5 cases. In our study there were no recorded cases of osteonecrosis of the jaw without the use of bisphosphonates.
The incidence of BONJ for those treated with oral bisphosphonates for osteoporosis was 0.1%.
Conclusion: Studies have shown a significant variation in the incidence of BONJ. This study suggests an incidence, in our population, higher than previously reported. The reason for this is not clear.