Comparison of indirect calorimetry and other predictive equations on determination of resting energy expenditure of patients with endocrine disorders

The purpose of this study was to specify the equations yielding the most accurate result for the determination of energy requirments of outpatients with endocrine disorders by comparing the indirect calorimetry results with predictive equations. This study was conducted with 150 patients (female 74%, male 26%) aged between 18 and 86 whose basal metabolic rate was measured by indirect calorimetry (IC) (COSMED, Fitmate GS), having applied to Başkent University Ankara Hospital Endocrinology Department between the dates of December 2016-February 2017 and voluntarily participated in this study. Personal information and lifestyles related to the individuals were examined by questionnaire form. The anthropometric measurements and results of body composition analysis were recorded to the questionnaire form. Furthermore, basal metabolic rates (BMR) of the individuals were calculated with 42 different predictive equations by using the anthropometric measurements and body compositions of them. While 66% of the individuals participated in the study ranged from 18 to 64 years of age, 34% of them were above 65 years and their total average age was 54.6±16.32 years. Of these individuals were diagnosed with diabetes/insülin resistance (51.3%), hypertension (37.3%), thyroid diseases (80.0%), obesity (26.7%), bone diseases (10.0%), dyslipidemia (60.0%), reproductive system diseases (12.7%) and hypoglycaemia (4.7%). It was specified that the usage of HB 1984 equation on the determination of BEE would give the most accurate result when it was impossible to use IC for the patients with endocrine disorders (p<0.05). When it was impossible to use IC for male patients with endocrine disorders, Lazzer (BC) equation, which had the best correlation according to Intraclass Correlation Coefficient (ICC) and which can indicate 66.8% of the IC results, gave the most accurate results (p<0.05). When it comes to females having endocrine disorders, any predictive equation having a sufficient statistical correlation could not be detected. The usages of predictive equations for adults and elders having endocrine disorders varied. It was determined that Nelson (BC) and Huang equations would give the most accurate results when it was not possible to use IC for adults having endocrine disorders (p<0.05). It was determined that HB 1984, HB 1919 and De Lorenzo equations would give the most accurate results when it was not possible to use IC for elders having endocrine disorders (p<0.05). Any predictive equation which can indicate more than 50% of IC measurement as a result of regression analysis for lean and normal individuals in regard to body mass index could not be determined. In a similar way, any predictive equation having the best correlation with IC according to ICC for lean and normal individuals could not be detected. When it was impossible to use IC for overweight patients having endocrine disorders on determination of BEE, it was determined that Henry equation would give the most accurate results. When it was not possible to use IC on determination of BEE for obese and morbidly obese individuals, Huang and Japanese (Simplified) equations would yield the most accurate results. Consequently, when it was impossible to use IC for the patients with endocrine disorders, it was specified that these equations gave the most accurate results, yet, it was specified that neither of these equations in the study would not be substitute for IC. In order to determine the equations to use as substitute for IC in this population, further studies should be conducted.Keywords: Basal metabolic rate, indirect calorimetry, predictive equations, endocrine disordersKA16/346 numbered and 07.12.2016 dated 'Ethics Committee Approval' is received by Başkent University Medical and Health Sciences Research Council.