Can We Use Bio Impedance for Resting Energy Expenditure? – Surely Yes!!

OBJECTIVE: To compare the accuracy of BIA and Indirect calorimetry. MATERIAL AND METHODS: Study area: ICU, SL Raheja Hospital. Study population: Health care workers- healthy individuals. Study design: Prospective comparative study. Study duration: From IEC approval date till 18 months. Sample size: This calculator uses the following formula for the sample size n: As in the present study, both BIA and IC were performed on same group of subjects, the total sample size was considered 50. The sample size was calculated using the computation for difference between 2 means, with level of significance at 0.05 and power set at 95%. Values for the difference in mean and standard deviation were based on a similar study by Sybil CL et al, wherein the mean BMR estimated using BIA was 1675±260 kcal/day and the mean BMR measured using IC was 1413±252 kcal/day.(9.) All measurements were performed early in the morning after a fasting period of 8–10 h according to standardized conditions, i.e., abstention from alcohol, smoking, and vigorous physical activity for 24 h prior to the assessment. Bio impedance Analysis will be performed at 50 kHz INBODY, KOREA) at room temperature. The BIA variables considered (data produced by the device) were- resistance (R), reactance (Xc), and phase angle (PhA). Bioimpedance index (BI-index) was calculated as the ratio height(2)/resistance (cm(2)/0). Formula for resting energy expenditure (REE) using Bioimpedance analysis:(7.) For Males For Females Resting Energy Expenditure (REE) was measured by indirect calorimetry [24] using a canopy system (COSMED Q-NRG, ITALY). The formula to calculate resting energy expenditure (REE) using indirect calorimetry (IC) is: Modified Weir equation: REE = [Vo2 (3.941) + Vco2 (1.11)] × 1440(4.) Through this study we tried to conclude if the accuracy of the methods used for measuring Rest energy expenditure can further aid in diagnoses and nutrition of healthy patients which can used as a baseline with patients admitted with illnesses. RESULTS: The mean REE by IC was found to be 1601±376 and that by BIA was 1554±355. Mean REE calculated by BIA and IC was compared using t test. The results depicted no significant difference in the mean REE calculated by IC and BIA (p value = 0.69 > 0.05) inferring that values of REE by BIA are more similar to REE by IC. CONCLUSION: The study concludes that BIA can be used to calculate REE as appropriate as IC.