Bone Mineral Density Reporting Underestimates Fracture Risk in Ontario

Analysis of clinical documents such as bone mineral density (BMD) reports is an important component of program evaluation because it can provide insights into the accuracy of assessment of fracture risk communicated to patients and practitioners. Our objective was to compare fracture risk calculations from BMD test reports to those based on the 2010 Canadian guidelines.

We retrieved BMD reports from fragility fracture patients screened through a community hospital fracture clinic participating in Ontario's Fracture Clinic Screening Program. Fracture risk was determined according to the 2010 Canadian guidelines using age, sex, and T-score at the femoral neck, in addition to three clinical factors. Three researchers classified patients' fracture risk until consensus was achieved.

We retrieved reports for 17 patients from nine different BMD clinics in the Greater Toronto Area. Each patient had a different primary care physician and all BMD tests were conducted after the 2010 Canadian guidelines were published. The fracture risk of 10 patients was misclassified with 9 of the 10 reports underestimating fracture risk. Nine reports acknowledged that the prevalence of a fragility fracture raised the risk category by one level but only four of these reports acknowledged that the patient had, or may have sustained, a fragility fracture. When we raised fracture risk by one level according to these reports, eight patients were still misclassified. Fracture risk in the majority of these patients remained underestimated. Inconsistent classification was found in the majority of cases where reports came from the same clinic. Four reports described risk levels for two different types of risk.

More than half of patients received BMD reports which underestimated fracture risk. Bone health management recommendations based on falsely low fracture risk are likely to be sub-optimal.