Bisphosphonate-related osteonecrosis of the jaw in four Nordic countries and an indication of under-reporting

Abstract

Objective. To assess reported cases of bisphosphonate-related osteonecrosis of the jaw (BONJ) to Medicines Agencies (MAs) in four Nordic countries and to compare the Norwegian MA data with BONJ cases retrieved through an e-mail survey to Oral and Maxillofacial Surgeons (OMS) in Norway. Material and methods. BONJ cases reported to the national MAs in each country from January 1st 2003 to September 30th 2010 were collected. An e-mail survey was sent to all active members of the Norwegian Association of Oral and Maxillofacial Surgeons (n = 54) included questions on total BONJ cases seen in practice and route of drug administration during January 1st 2003 to December 31st 2009. Results. In total, 253 BONJ cases were reported to the MAs; 39 in Denmark, 44 in Finland, 51 in Norway and 119 in Sweden. These figures result in cumulative incidences (multiplied by 100,000) of 0.7, 0.8, 1.1 and 1.3, respectively. Intravenous administration was reported in 169 of the cases. The e-mail survey resulted in 35 responses reporting 214 BONJ cases, 4-times more cases than reported to the MA. Conclusions. Cumulative incidence of cases reported in this study differs to some degree in the four Nordic countries (Denmark < Finland < Norway < Sweden). In Norway, almost the same number of BONJ cases were reported through the questionnaire by OMS as in all four countries together (214 by OMSs vs 254 to MAs) and included a high number after per oral administration. The present results indicate a notable under-reporting in Norway and most likely in other Nordic countries.