O048. - COMPARATIVE ANALYSIS OF BASAL METABOLIC RATE MEASUREMENT METHODS IN PATIENTS WITH INTESTINAL FAILURE ON HOME PARENTERAL NUTRITION

O048.

COMPARATIVE ANALYSIS OF BASAL METABOLIC RATE MEASUREMENT METHODS IN PATIENTS WITH INTESTINAL FAILURE ON HOME PARENTERAL NUTRITION

M. Majerr^1,*, D. Mlakar Mastnak¹, L. Petrica¹, L. Majdič¹, N. Palamar¹, T. Slapar¹, N. Kozjek Rotovnik^1,2,3

¹Department of Clinical Nutrition, Institute of Oncology Ljubljana, ²Faculty of Medicine | University of Ljubljana , Ljubljana, ³Faculty of Medicine University of Maribor, Maribor, Slovenia

Rationale: Accurate estimation of basal metabolic rate (BMR) is essential to prevent underfeeding or overfeeding in patients with intestinal failure (IF) requiring home parenteral nutrition (HPN). Bioelectrical impedance analysis (BIA) is a commonly accessible and non-invasive technique, yet its accuracy compared to indirect calorimetry (ICAL), the gold standard, is still uncertain. This study aimed to assess the correlation and systematic differences between BIA and ICAL measurements.

Methods: A retrospective study was conducted on 32 patients with IF on HPN to assess BMR using two methods: BIA and ICAL, performed on the same day under standardized conditions. Pearson’s and Spearman’s correlation coefficients were calculated to assess the relationship between methods. Bland-Altman analysis was performed to evaluate systematic bias and limits of agreement (LoA). A paired t-test and Wilcoxon signed-rank test were used to determine statistical differences between methods. 

Results: The average measured value of BMR measured by BIA was 1416.16 ± 220.07 kcal/day and of REE by ICAL was 1675.69 ± 303.89 kcal/day. Pearson’s correlation coefficient was r = 0.68 (p < 0.001), and Spearman’s coefficient was ρ = 0.65 (p < 0.001), indicating a strong positive relationship between BMR by BIA and REE by ICAL. ICAL assessed REE value to be higher by 259.53 ± 221.79 kcal/day (mean bias, -259.53 kcal/d [ P = .00]; LoA, - 694.24 to 175.17 kcal/d). A paired t-test confirmed a statistically significant difference (t = 6.62, p < 0.001), supported by the Wilcoxon test (Z = -4.49, p < 0.001). 

Conclusion: Although BIA and ICAL demonstrated a strong positive correlation, BIA systematically underestimating BMR, limiting its standalone clinical utility and it may not be interchangeable with ICAL in clinical practice due to systematic bias. Further validation in larger cohorts is required.

Disclosure of Interest: None declared