Whole-body dual-energy X-ray absorptiometry (DXA) scanning can provide a useful indication of low skeletal muscle mass in patients with inflammatory bowel disease, Australian researchers have found.
The potential for recognition of patients with low skeletal muscle index (SMI) and help therapeutic decision making to treat inflammation, underscores the need for wider DXA assessment in clinical practice, they say.
A total of 54 patients with inflammatory bowel disease (IBD) at Melbourne’s Monash Health and 30 controls underwent full body composition assessment as part of the study, which involved whole-body DXA, BMI analysis, eating questionnaires and handgrip strength tests.
BMI scores did not differ significantly between IBD patients and controls (median 25 vs 23kg/m2), nor between those with active and inactive disease (26 vs 25).
And while DXA was a useful measure of detecting those with excess fat mass, it offered no advantage over simple BMI calculations, according to the team.
By contrast, DXA-derived data on skeletal body mass revealed one-in-six IBD patients as having concerningly low SMI compared with none of the controls, the researchers reported in European Journal of Gastroenterology & Hepatology (link here).
Of note, 17 IBD patients with active disease were initiated on biologic therapy as a result, nine of whom were deemed inflammatory responders with an 82–99.8% reduction in faecal calprotectin, they said.
“The presence of active inflammatory disease at the time of body composition study did not separate abnormal from normal composition,” they wrote.
“But successful induction therapy in those with active disease was associated with an increase in SMI as well as improved quality of life within ≥13 weeks of treatment, while non-responders showed no change in these body composition parameters.”
“Hence, accurate data on SMI provided unique insights into the consequences of illness in many patients.”
Another finding was that body composition was similar in 28 patients with active disease versus 22 with inactive disease.
Meanwhile, normal BMI was seen in many patients with low SMI, the researchers noted.
Additionally, handgrip strength was a poor marker of change in SMI, despite the findings of some previous studies, they said.
“While different techniques of arm positioning and dynamometer instruments may influence results between studies, longitudinal measurement in our cohort using the same equipment and technique, showed no change in handgrip strength with induction therapy, despite increasing SMI,” they said.
“In summary, all surrogate markers of low SMI performed poorly and were no substitute for DXA.”
The authors added: “While active inflammatory disease was not associated with abnormal body composition on cross-sectional assessment, successful induction therapy (but not lack of response) increased SMI, indicating that active inflammation is likely to be one factor in reducing skeletal body mass.”
“Clinical disease indices did not accurately reflect changes in intestinal inflammation or SMI with therapy.”
“Overall, this study indicates that patients are poorly stratified as at-risk of low SMI with available screening tools, and their recognition by DXA may influence therapeutic decisions.”