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P190. Low muscle mass in inflammatory bowel disease (IBD): common and predictive of functional sarcopenia and osteopenia

R. Bryant1,2, S. Ooi1, C. Schultz3, C. Goess1, R. Grafton1, J. Hughes1, F.D. Bartholomeusz1, J. Andrews1, 1Royal Adelaide Hospital, Gastroenterology and Hepatology, ADELAIDE, Australia, 2Oxford University Hospitals Trust, Translational Gastroenterology Unit, Oxford, United Kingdom, 3Royal Adelaide Hospital, Department of Nuclear Medicine, Adelaide, Australia

Background

Body composition is poorly studied amongst adult patients with IBD. Lean mass (LM) deficits may not be detected with standard clinical assessment, yet may be associated with considerable morbidity; reduced muscle performance, quality of life, and bone health. We sought to assess the potential prevalence of low LM and examine for associated morbidity in an adult IBD population.

Methods

Data were prospectively gathered on consecutive, premenopausal, 20–50 year old outpatients with IBD. Whole body dual energy X-ray absorptiometry (DXA) (GE - Lunar Prodigy) and height and weight measures were used to calculate body mass index (BMI) (weight [kg]/height [m]2), appendicular skeletal muscle index (ASMI) (appendicular lean mass [kg]/height [m]2), and bone mineral density (BMD) (g/cm2). Baseline data included: grip strength (validated dynamometer), IBD disease characteristics and therapy, nutritional indices, physical activity, and health-related quality of life scores (HRQoL). Z scores were calculated from standard deviation (SD) values of established age-specific normative data for ASMI [1], grip strength [2] and BMD [3]. Low LM was defined as ≥1SD below mean for ASMI. Sarcopenia was defined as ASMI AND grip strength ≥1SD below mean. Standard definitions were used for osteopenia/porosis [3]. Univariate and multivariate logistic regression and t-test analyses were performed.

Results

137 patients with IBD were enrolled; 76 (56%) male, 95 (69%) Crohn's disease, median age 31 (mean 32.2), mean BMI of 26.2 (median 25.1), and 78 (57%) active disease. Overall, 29/137 (21.2%) patients had low LM, 19/76 (25%) males, 10/61 (16%) females. Amongst those with low LM, 17/29 (58.6%) also had reduced grip strength, meeting our definition of sarcopenia. Neither low LM nor sarcopenia were associated with a reduced HRQoL (p 0.94, p 0.82 respectively). 52/137 (38%) patients had osteopenia or osteoporosis. Multivariate analysis revealed that low LM and sarcopenia, but not BMI, predicted the combined endpoint of osteopenia/osteoporosis (OR 4.4, 95% CI 1.4–13.5, p < 0.01; OR 6.3, 95% CI 1.4–27, p < 0.02; OR 0.9, 95% CI 0.9–1.0, p 0.14; respectively) (Table 1).

Table 1. Clinical predictors of osteopenia or osteoporosis a
VariableUnivariate analysisMultivariate analysis
OR95% CIp valueOR95% CIp value
Diagnosis: ulcerative colitis vs Crohn's disease0.640.3–1.40.26
Disease duration b1.011.0–1.1<0.01*1.101.0–1.2<0.01*
Steroids (≥12 months, <12 months)2.031.1–9.60.03*1.770.7–4.50.227
Faecal calprotectin (<100 vs ≥100 µg/g)0.830.4–1.80.64
Serum 25-Vitamin D level (<60 vs ≥60 nmol/L)1.030.5–2.10.94
Physical activity c0.630.3–1.30.21
Alcohol intake d1.00.6–6.21.00
Smoking (current/ex-smoker vs never)1.220.6–2.50.58
Body mass index b0.950.9–1.00.14
Low ASMI2.461.1–5.70.03*4.381.4–13.5<0.01*
Sarcopenia e3.291.1–59.60.03*6.311.4–27.9<0.02*
*p < 0.05 statistically significant.
a Combined endpoint. World Health Organization definition: osteopenia 1–2.5 standard deviations (SD), osteoporosis >2.5SD below mean for young adults (T-score).
b Continuous variable.
c International Physical Activity Questionnaire: low vs normal/high.
d Alcohol intake: >20 g/day vs ≤20 g/day.
e Sarcopenia: defined as ≥1SD below age-matched mean for Appendicular Skeletal Muscle Index (ASMI) and grip strength.

Conclusion

Despite normal BMI, low LM is common in patients with IBD, affecting 25% of males. Low LM is commonly associated with reduced muscle performance constituting functional sarcopenia. Recognition of low LM is important in patients with IBD given its value in predicting bone health issues, which may be otherwise unsuspected and are not predicted by BMI.

1. Kelly TL, Wilson KE, Heymsfield SB (2009), Dual Energy X-Ray Absorptiometry Body Composition Reference Values from NHANES. PloS ONE, 4(9): e7038. doi: 10.1371/journal.pone.ooo7038.

2. Mathiowetz V, Kashman N, Volland G et al. (1985), Grip and Pinch Strength: normative data for adults, Arch Phys Med Rehabil, 66: 69–7.

3. World Health Organization (1994), Reference ranges for osteopenia and osteoporosis.