EVALUATION OF REST ENERGY EXPENDITURE IN PATIENTS WITH NON ALCOHOLIC FATTY LIVER DISEASE.

Background: Non-alcoholic fatty liver disease (NAFLD) is currently considered a global public health problem, with changes in lifestyle being the effective way to treat the disease. To date, there is no recommended standard of assessment to determine the resting energy expenditure (REE) of patients with NAFLD, so that dietary therapy can be properly guided.

Objective: To evaluate the REE of patients with NAFLD through indirect calorimetry and compare with different predictive formulas of REE and with REE by electrical bioimpedance analysis (BIA). Assess body composition through BIA, with NAFLD staging and the presence of comorbidities.

Methods: They were evaluated in patients with NAFLD over 18 years of age treated at the Gastroenterology outpatient clinic of a tertiary level hospital in southern Brazil. NAFLD staging was performed using liver biopsy or a non-invasive method. Weight, height and body mass index (BMI) were determined in all patients. The short version of the International Physical Activity Questionnaire was used to assess physical activity. Comorbidities as arterial hypertension, diabetes mellitus and dyslipidemia were evaluated. To estimate energy expenditure at rest, Harris-Benedict, Jeor Mifflin-St, World Health Organization and Schofield formulas were used. BIA was used to assess resting metabolic rate (RMR) and body mass, and to measure RMR, indirect calorimetry was also used. Associations between categorical variables were tested with Pearson's χ2 test and between groups with McNemar's test. The level of significance assumed was 5%. The degree of agreement between the REE measurement methods was assessed using the Blan-Altman test.

Results: A total of 67 patients were evaluated, 70.5% male, with a mean age of 59 years and a mean BMI of 33.08 kg/m2 ±5.13. The average RMR per CI was 1,753 kcal ±614.58. When comparing the RMR estimate by different formulas with indirect calorimetry, only the Jeor Mifflin-St formula showed a statistically significant difference (P=0.0001), with a difference of +318.49 kcal. BIA and Harris Benedict's formula presented values closer to CI, 1,658 and 1,845 kcal respectively.

Conclusion: We suggest that the Jeor Mifflin-St formula should not be used to estimate the RMR in patients with NAFLD. In the absence of indirect calorimetry, some alternatives can be used safely in this population, such as BIA and the predictive formulas of Harris Benedict, Schofield and the World Health Organization.