Proposed Topic (Most preferred): :
Clinical Safety and Quality Service I (Projects aiming to improve efficiency and effectiveness of care delivery to meet international standards)
Authors (including presenting author) :
Cheung TF (1), Chan CS (1), Koo HW (1)
Affiliation :
Dietetics Department, NTWC
Introduction :
The prevalence of morbid obesity is increasing all over the world and bariatric surgery is one of the treatments. Achieving weight reduction prior to bariatric surgery is essential. However, it is challenging for estimation of energy requirement in this group of patients in order to reduce fat mass with maintenance of muscle mass. Currently application of various predictive equations could be inaccurate and causing over-estimation of energy requirement. Indirect calorimetry (IC) is considered as the gold standard of energy requirement estimation and it is widely applied in patients in intensive care unit or used for validating predictive equations. However, there is limited evidence on the use of indirect calorimetry for patients in out-patient setting.
Objectives :
To determine the difference between basal metabolic rate (BMR) measured by IC and energy requirement estimated by different equations commonly used in clinical practice.
Methodology :
Patients referred for bariatric surgery work-up or with BMI>=30 were invited to perform IC to assess BMR. Various predictive equations (Singapore, Harris-Benedict, Liu’s, Henry, Yang, Mifflin, Owen and rule of thumb) were applied to estimate BMR. Estimated values by equations were compared with BMR measured by IC. Correlation and Bland-Altman Plot were performed for comparison between IC and different estimated values.
Result & Outcome :
42 subjects were recruited between April 2023 and December 2023. 19 (45%) of them were female and the BMI was between 30.03 and 77.08. Correlations between IC and all predictive equations were significant (all p<0.01) and the correlation coefficient among all equations and indirect calorimetry ranged between 0.70 and 0.76. Biases between IC and Henry, Mifflin and Owen were within +-100kcal and their biases were insignificant. Liu’s, Yang and rule of thumb showed bias up to ~600kcal. Standard deviation could be up to 400kcal while most of them were around ~300kcal. IC could be used in obese subjects planning for bariatric surgery for better estimation of energy requirement for individualized intervention. If IC is not available, some equations including Henry, Mifflin and Owen could be considered as these 3 equations showed biases within 100kcal in this small scale study. Due to non-sedated state of subjects, the accuracy of caloric requirement measured by IC might not be as accurate as patients in ICU (most are sedated). More subjects could be included and development could be considered for better measurement.
