PURPOSE

This study aimed to validate a predefined algorithm for osteonecrosis of the jaw (ONJ) among cancer patients in the Danish National Registry of Patients and to assess the nature of clinical information recorded in medical charts of ONJ patients.

METHODS

We identified potential ONJ cases recorded in 2005-2010 among cancer patients at the hospital Departments of Oral and Maxillofacial Surgery (DOMS) in three Danish regions, using a set of codes from the International Classification of Diseases, 10th revision (ICD-10). We abstracted DOMS charts of the potential cases, had the ONJ status adjudicated by an expert ONJ adjudication committee (ONJAC), and computed positive predictive values. For patients with ONJAC-confirmed ONJ, we abstracted the charts for information on ONJ clinical course. Sensitivity of the algorithm was computed using a separate sample of 101 known ONJ cases accrued in 2005-2011.

RESULTS

We identified 212 potential ONJ cases, of which 197 (93%) had charts available for abstraction. Eighty-three potential cases were confirmed by ONJAC, with a positive predictive value of 42% (95% confidence interval [CI] 35%-49%). DOMS charts of these 83 cases contained complete information on ONJ clinical course. Information about antiresorptive treatment was recorded for 84% of the patients. Among the 101 known ONJ cases, 74 had at least one prespecified ICD-10 code recorded in the Danish National Registry of Patients within ±90 days of the ONJ diagnosis (sensitivity 73%; 95%CI [64%-81%]).

CONCLUSIONS

The predefined algorithm is not adequate for monitoring ONJ in pharmacovigilance studies. Additional case-finding approaches, coupled with adjudication, are necessary to estimate ONJ incidence accurately.