Hepatite c crônica e composição corporal: relevância e complementaridade dos métodos de avaliação da massa livre de gordura

Abstract

Introduction: Malnutrition can be identified in 13.0% to 90.0% of patients with liver cirrhosis. These conditions contribute to loss of skeletal muscle mass, quality, and strength that is called sarcopenia. Despite its relevance in liver disease, there was no universal consensus to define and diagnose sarcopenia in this population. Thus, the objective of the two studies that integrate this thesis was to evaluate the health of skeletal muscle in patients chronically infected with HCV. In the first study, we prospectively, included 209 CHC patients, randomly allocated into two groups, 158 patients in a development model (derivation sample) and 51 patients in a validation group (validation sample). Predictive equations were developed using backward stepwise multiple regression and the most adequate and simplest derived predictive equation was further explored for agreement and bias in the validation sample. The accuracy of the predictive equation was evaluated using the coefficient of determination (R²). In this first step, the predictive equation with an optimal R² was developed: Fat-Free Mass (Kg) = Sex × 0.17 + Height (m) × 16.83 + Weight (Kg) × 0.62 + Waist Circumference (cm) × (- 0.15) + Weight (Kg) × Sex × (- 0.30) + Sex × Waist Circumference (cm) × 0.14 - 6.23; where sex = 1 for female and 0 for male. R² = 0.93, standard error of the estimate = 2.6 Kg and coefficient of variation = 20.0%, p <0.001. Our developed and cross-validated anthropometric prediction equation for fat-free mass estimation by using BIA attained a high coefficient of determination, a low standard error of the estimate, and lowermost coefficient of variation. In conclusion, predictive equations may be reliable and useful alternative methods for clinical evaluation of fat-free mass in patients with CHC. The objective of the second study was to appraise the degree of agreement between the original European Working Group on Sarcopenia in Older People (EWGSOP1), the revised EWGSOP2, and The Foundation for the National Institutes of Health Biomarkers Consortium Sarcopenia Project (FNIH) consensuses to assess the skeletal muscle status in patients with chronic hepatitis C (CHC). We also evaluated if the prevalence of sarcopenia and its associated factors differ when the three consensuses were used to assess the skeletal muscle status in these patients. One hundred and three CHC patients [mean age, 50.6 ± 11.3 years; 74.8% males; 67.0% non‐cirrhotic; 33.0% with compensated cirrhosis], prospectively, underwent scanning of the lean tissue, appendicular skeletal muscle mass (ASM), fat mass, lumbar spine, hip, femoral neck, and whole‐body bone mineral density (BMD) by dual‐energy X‐ray absorptiometry. Muscle strength was assessed by dynamometry. Sarcopenia was defined as the presence of both low, ASM/height2 (ASMI) or ASM/body mass index (ASMI, ASM/BMI), and low muscle strength according to each of the three used consensuses. Nutritional status evaluation was based on the Controlling Nutritional Status score. The best agreement was observed between EWGSOP1 and EWGSOP2 [Kappa coefficient = 0.83; 95% confidence interval (IC) = 0.63 - 1.0] and the worst agreement was observed between EWGSOP1 and FNIH [Kappa coefficient = 0.33; 95%CI = 0.05 - 0.63]. The prevalence of sarcopenia was 8.7%, 9.7% and 9.7% according to EWGSOP1, EWGSOP2 and FNIH consensuses, respectively. Sixteen (15.5%) patients with CHC had sarcopenia by one or more of these three consensuses. Six (37.5%) patients fulfilled at least one consensus [FNIH (n = 5) or EWGSOP1 (n = 1)]. Seven patients (43.8%) met two consensuses [EWGSOP1 and EWGSOP2 (n = 5; 31.3%); EWGSOP1 and FNIH (n = 1; 6.3%); EWGSOP2 and FNIH (n = 1; 6.3%)]. Three patients (18.8%) were considered sarcopenic by the three consensuses. Considering the patients who met one or more criteria among the three consensuses, 93.8% (15/16) of them had low muscle strength based on revised cut-offs, excluding one sarcopenic patient who met EWGSOP1 criterium. Sarcopenic obesity frequency was 56.3% and 6/9 (66.7%) by FNIH consensus. Sarcopenia was inversely associated with bone mineral content (P=0.004). In conclusion, to the best of our knowledge, this is the first study to demonstrate that the revised EWGSOP2 did not affect the diagnosis of sarcopenia in CHC. In overweight patients, the ASMI adjusted by BMI appears to be more appropriate for diagnosing sarcopenia in patients with CHC. Handgrip strength testing should be incorporated into routine clinical practice to screen the muscle skeletal status in CHC patients, independently of the stage of the liver disease.