Osteoporosis may be over-treated with non-diagnostic DEXA scan results

1. In this retrospective cohort study, two-thirds of new osteoporosis drug prescriptions were potentially inappropriate as diagnosis was based on non-International Society of Clinical Densitometry recommended sites.

2. Of these potentially inappropriate prescriptions, half were given to younger women without osteoporosis risk factors who may not have needed screening.

Evidence Rating Level: 2 (Good)

Study Rundown: The International Society for Clinical Densitometry (ISCD) recommends that the dual-energy x-ray absorptiometry (DEXA) T-scores of a woman’s anterior-posterior spine and femoral neck should be used for the diagnosis of osteoporosis. However, some regional health care systems report T-scores for other anatomic sites (e.g. the lateral lumbar spine). These reporting practices may result in over-diagnosis and thus overtreatment of osteoporosis. This study aimed to examine a regional health care system where DEXA reports scores for non-ISCD recommended sites and determine the frequency of osteoporosis overtreatment.

Of the women who received new osteoporosis drug treatment after their initial DEXA scan, 66.4% were diagnosed with DEXA reports that stated osteopenia but no osteoporosis, or osteoporosis of non-ISCD recommended sites. This may indicate that there is indeed overtreatment of osteoporosis in regions where DEXA scores report T-scores of non-ISCD recommended sites. These women were more likely to be younger without osteoporosis risk factors. A limitation of this study includes only using one regional health care system and thus impacts its generalizability to other regions where non-diagnostic T-scores are not listed on DEXA scan reports.

Click to read the study, published today in JAMA Internal Medicine

Relevant Reading: Executive summary of the 2013 International Society for Clinical Densitometry Position Development Conference on bone densitometry.

In-Depth [retrospective cohort]: This retrospective study created their study cohort using electronic health records of women 40 to 85 who received their first DEXA scan in the UC Davis health system from January 2006 to December 2011. All women were osteoporosis treatment-naïve. T-scores from the anterior-posterior spine and femoral neck were deemed ISCD recommended, whereas T-scores from lateral lumbar spine, ward triangle of hip, forearm and radius were deemed non-ISCD recommended. All T-scores were classified as normal (T>-1.0), osteopenic (-2.5<T≤-1.0) and osteoporotic (T<-2.5). Each DEXA report was categorized depending on whether an ISCD recommended or non-recommended site was osteopenic or osteoporotic. Prescription data was used to determine which women received new prescriptions for osteoporosis medications in the year of or following the initial DEXA scan.

Of the 6150 women who received DEXA scans in the study period, 1912 (31.1%) received new osteoporosis drug treatment. Just over 14% of all women had ISCD recommended site osteoporosis, 32.8% had non-ISCD recommended site osteoporosis, and the remaining 53.1% of women had isolated osteopenia or normal T-scores. Most women with ISCD recommended site osteoporosis (73.5%; 95%CI 70.4%-76.4%) received new drug therapy as compared to approximately half of women with non-ISCD recommended site osteoporosis (47.7%; 95%CI 45.5%-49.9%). However, given that women with non-ISCD recommended site osteoporosis or isolated osteopenia were so common, 50.3% (95%CI 48.0%-52.5%) of all new osteoporotic drug prescriptions were given to women with non-ISCD recommended site osteoporosis and 15.8% (95%CI 14.2%-17.5%) were given to women with isolated osteopenia.

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