Bone Abstracts

NICE guidelines (UK) recommend that bone mineral density (BMD) scans, corrected for bone size (bone mineral apparent density [BMAD]) should be performed for patients with anorexia nervosa (AN) when underweight for a year or more. The number of patients identified with low bone mineral density or vertebral fractures remains low in this population. However, referrals for dual- energy X-ray absorptiometry (DXA), vertebral fracture assessment (VFA) and peripheral quantitative computed tomography (pQCT) have increased significantly, over the last few years.

Method: We retrospectively reviewed AN patients referred for scanning over a 5 year period to observe the number identified with low BMD as per the ISCD 2013 guidelines. Vertebral and long-bone fractures were also recorded by interrogating our local imaging archive system. Demographic data, bone health history and baseline BMD parameters was collated.

Results: Sixty-two (62) patients were identified (58 female and 4 male). Eight patients had a BMAD Z-score < −2.0 however only one had evidence of a mild vertebral fracture with no long-bone fractures reported. One patient had a Total Body Less Head (TBLH) Z-score < 2.0 but with no evidence of vertebral or long bone fractures. Four patients had pQCT total, trabecular and cortical content Z-score <2.0 with no evidence of vertebral fracture and one reported long bone fracture. However, thirty-nine patients had muscle area for height Z-scores <2.0. Of five patients with vertebral fractures, four had reduced muscle area. Similarly, of twelve patients with long-bone fractures, six had reduced muscle area.

Conclusion: Our findings confirm that incidence of decreased BMD and vertebral fractures in adolescents with anorexia nervosa is low. Low muscle mass rather than bone density is a better predictor of fractures. Therefore body mass index criteria should be incorporated into the referral criteria for bone health surveillance in AN patients rather than duration of anorexia alone.

https://www.nice.org.uk/guidance/ng69/evidence-Accessed 08/02/2019

Disclosure: The authors declared no competing interests.