Endocrine Abstracts

Introduction: The WHO recommends that osteoporosis be diagnosed based on the lowest T score in hip, spine or distal 33% radius. Indian guidelines emphasize T score based diagnosis and treatment of osteoporosis..One of the reasons for measuring bone density is to account for differences in bone density between sites. The data on discordance in bone density between the hip, spine and distal radius is scarce in India - despite DXA scanning being available in India for the last 20 years. If there’s a significant discordance between hip and spine, this can potentially have impact on the diagnosis of osteoporosis. With the currently available options for treatment of osteoporosis, such discordance would raise the question of selective targeting of hip or spine, depending on bone density. Thus it is important to know the prevalence of clinically meaningful discordance and its predictors in Indian patients.

Materials and methods: This was a retrospective study in which individuals who underwent BMD measurement and FRAX scoring at Sri Ramachandra Medical Centre, Chennai during the time period July 2016 to July 2018 were included. Those who have already received treatment with US Food and Drug Administration (USFDA) approved drugs for osteoporosis were excluded. Height and weight were measured using standard medical scales. Femoral neck BMD and T-score were obtained from the DXA scanner. DXA was done using the same machine for all the subjects (GE Lunar Prodigy Advance enCORE™ Version 13.60).

Discordance in the classification between hip and spine was noted. Minor discordance was defined as one step classification difference ( Normal in one site and osteopenia in the other or Osteopenia in one site and osteoporosis in the other). Major discordance was defined as maximum difference in classification between sites – normal in one site and osteoporosis in the other. The analysis was repeated with ICMR normative data. Ordered logistic regression, with all the variables used in FRAX calculation, was used to identify predictors of discordance.

Results: The study included 808 adults, both men and women, above the age of 50. The mean age(sd) was 58.7 (6.2) years. The group had 56.8% men. None of the patients were taking any osteoporosis medications. In 58.2% of patients, no discordance was seen. In 2% of patients major discordance was seen and 39.9% of patients had minor discordance.

Conclusion: Hip spine Discordance is seen in 4 out of 10 patients undergoing DEXA scan.