Evaluation of proposals of Belgian Social Security Institute for reimbursement of bone densitometry tests. Toward a costeffective strategy for osteoporosis screening?

Background and aims: The Belgian Social Security Institute (hereafter INAMI) proposes a list of conditions to be considered as a prerequisite for reimbursement of Bone Mineral Density (BMD) measurements. The aim of this paper was to evaluate the diagnostic accuracy of the proposed criteria for identifying osteoporosis, and to gauge how useful they are for more rational application of densitometry tests. Methods: 3748 Caucasian women aged at least 50 years old were recruited consecutively from an outpatient university center, from the database of which all relevant data corresponding to the INAMI list of clinical factors, as well as patients’ age, weight and height, were collected. BMD measurements using dual X-ray absorptiometry were reported at the spine and hip regions. Diagnostic accuracy was evaluated through measures of sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Additionally, from ROC analysis, benchmark values for age and body mass index were identified and then, used alone and in combination with the INAMI test, were applied to define various screening strategies. For each of them, associated costs per osteoporotic patient detected were estimated. Cost estimates refer only to the costs associated with the densitometric procedure from the perspective of the reimbursement health authorities. Results: Applying INAMI criteria for detecting osteoporosis at any of the considered sites yielded sensitivity of 68.9%, specificity of 50.7%, PPV of 42.9% and NPV of 57.3%. Comparison of incremental costs per patient of the different strategies revealed that, with 67.1 Euros, the option of opening BMD coverage to women on the basis of the INAMI conditions would be more cost-effective than mass screening (90.1 Euros) or applying the age criterion alone (70.2 Euros). However, the BMI condition seems to act as a better indicator of risk than the INAMI criteria in those meeting the age condition (35.4 Euros). Conclusions: The accuracy of the INAMI proposal turns out to be quite unsatisfactory, and did not adequately cover the population at risk of osteoporosis. From a resource allocation perspective, the best strategy by far would be to recommend using concomitantly INAMI, age and BMI-selective criteria. Some adaptations could enhance the usefulness of the INAMI proposals as a selective approach for BMD referral and reimbursement.