Low Phase angle is a marker of deteriorated nutritional status and indicates a more active and endoscopically severe...

Malnutrition is a common complication in inflammatory bowel disease (IBD) but is frequently underdetected. Phase angle (PhA), a bioelectrical impedance parameter (BIA), is considered an indicator of membrane cell integrity and overall health. The primary aim of this study was to investigate the association between PhA and nutritional status in adult patients with IBD. Secondary aims were: (i) to compare PhA values of IBD patients with age-, sex- and BMI-standardized reference values; (ii) to explore the associations of PhA with body composition, handgrip strength and laboratory markers; (iii) to evaluate the diagnostic accuracy of PhA for the detection of malnutrition; and (iv) to investigate the associations of PhA with disease activity and endoscopic severity.

Adult outpatients diagnosed with Crohn's Disease (CD) or ulcerative colitis (UC) were included in this double-center cross-sectional study. Data regarding nutritional status, body composition, muscle function, disease activity, endoscopic severity and blood tests were obtained through BIA, validated scores and ileocolonoscopy. Statistical software was employed for data analysis.

A total of 144 IBD (96 CD and 48 UC) patients participated in the study with a median PhA of 5.7°, significantly lower to age/gender/BMI-standardized reference values (6.03°,p=0.018). PhA was statistically significantly (p<0.01) strongly correlated with nutritional status, handgrip strength (r=0,700), hematocrit (r_s=0.621), lean mass (r=0.591), body cell mass (r=0.518), height (r=0.517) and albumin (r_s=0.516,) and was statistically significantly (p<0.05) lower in patients with malnutrition (4.71°vs5.7°), active (5.14°vs6.10°,p=0.009) and endoscopically mild-to-severe disease (5.29°vs5.84°). Patients with low PhA tend to have higher inflammatory markers and a cut-off of 6.25° identified malnutrition with 87.5% sensitivity (28/32; 95%CI=71.9 to 95.0%) and 43.8% specificity (49/112;95%CI=34.9to53.0%) and 92.5% NPV (49/53;95%CI=82.1to97.0%).

PhA is simple and easily obtainable BIA parameter that reflects nutritional status and systemic disease burden. Although its clinical application can facilitate the early detection of malnutrition, further prospective studies are required to establish its prognostic role.