Bis-Phosphonates & Osteo-Necrosis of the Jaw ('Dead Jaw Syndrome')
Update, December 2012
British Dental Journal 213, 594 (2012)
Published online: 21 December 2012
The findings of a 2-year national, new patient registration of patients with avascular necrosis of the jaws including Bisphosphonate-Related Necrosis (BRONJ) referred to Oral Surgery, Oral Medicine, Oral & Maxillofacial Departments & Dental Hospitals in England, Wales, Scotland and Northern Ireland have been published.
Bis-phosphonate-Related Osteonecrosis of the Jaw (BRONJ) is rare.
A 2 year national study based on patient case records has concluded that incidence of Bisphosphonate-Related Osteonecrosis of the Jaw (BRONJ) can be considered as rare.
This study, a collaboration between the Faculty of General Dental Practice (UK) (FGDP [UK]) and the British Association of Oral & Maxillofacial Surgeons (BAOMS), was designed to capture all new referrals of patients with avascular necrosis of the jaw, including BRONJ, to Oral & Maxillofacial departments & dental hospitals in England, Wales, Scotland and Northern Ireland, from June 2009 to May 2011.
One of the 2 clinical leads for the study was Professor Simon Rogers for BAOMS, who commented: “Although the data need to be interpreted with caution, the report would suggest that there are around 600 cases of BRONJ each year in the UK, and around 400 of these are related to oral bis-phosphonates. Considering how commonly bis-phosphonates are prescribed for conditions such as osteoporosis, these results should serve to reassure the public given the relative small number of cases of BRONJ each year. Further data and research is required”.
The 2 year study is the first of its kind. It allows patients & healthcare professionals to get a better understanding of the likely rates of BRONJ. From the study, it was estimated that in the UK (England, Wales, Scotland and Northern Ireland), there were approximately 620 (508 - 793) cases / year. Although caution needs to be applied to the interpretation of rates in post-menopausal women with osteoporosis treated with an oral bisphosphonate, the rate was estimated at between 1 in 1,260 to 1 in 4,420 per year. Thus, BRONJ can be considered as a rare or very rare condition depending on the patient group studied.
Accepting that there has been a degree of under-reporting of new cases nationally, the best estimate of incidence is that BRONJ occurs in 10 patients per year per million population. For women, the estimated rate is 14 per million per year and for men, 6 per million per year. In women aged 70 - 79 years, the rate is in excess of 50 patients per million per year. As the elderly population and associated bis-phosphonate prescribing increases, it is expected that the number of BRONJ cases presenting each year will increase over time assuming that other risk factors remain constant. These estimates of incidence if applied to the current UK population of 62 million people, would indicate a total of 620 (508 - 793) BRONJ cases a year.
It was estimated that the incidence of BRONJ in a population of post- menopausal woman with osteoporosis and treated with an oral bisphosphonate developing BRONJ as being somewhere between 1 in 1,262 & 1 in 4,419 per year. Interpretation needs to be very cautious given the number of assumptions involved but if the logic is appropriate then this risk can therefore be regarded at worst as ‘rare’ (occurring ≥ 1/10,000 to < 1/1,000). The risk of developing BRONJ has to be balanced against the risk and subsequent outcome following fracture neck of femur and vertebral fractures. The incidence of BRONJ for patients receiving bis-phosphonates for cancer is likely to be higher but too few data are available to make an estimate.
Two-thirds of cases (69%) were female and the overall mean age was 69 years. In 56% of cases, the route of administration was oral (34%), IV (7%) both oral and IV and unknown for 2%. This high percentage of cases with oral administration probably reflects the predominance community prescribing of oral bis-phosphonates.
In patients who had received oral treatment, the majority (71%) had taken alendronic acid. In patients, who had received IV treatment, the majority (61%) were given zoledronic acid.
In 73% of patients, the precipitating event was a dental extraction. Pain (74%), discharge (46%) & swelling (43%) were the main symptoms stated. In 8% of cases, the presentation was said to be asymptomatic.
The site of BRONJ was more often the mandible (lower jaw) than the maxilla (upper jaw) in a ratio of 2:1. Sites were predominantly in the molar region and evenly spread between right & left.
The number of BRONJ cases will increase in the years to come.