To exclude the possibility of bias, a preliminary comparative evaluation of the data between the two participating centres was performed. No significant differences were found in any of the parameters studied among comparable groups between the two centres. Thus, the data from the two centres were pooled and evaluated together. In the NAFLD group, we found a majority of cases with NASH, the proportion of those with pure fatty liver being 31% (data not shown).
The descriptive data of the 372 subjects included in the present study are shown in and . There were significant differences between the NAFLD, HCV and control groups in all parameters evaluated (). In particular, NAFLD patients showed significantly higher BMI, waist girth, serum cholesterol and triglycerides, and steatosis grade than HCV patients. The proportion of men was greater both in NAFLD and in HCV. However, the prevalence of men in those with HCV with steatosis was much higher than in those without steatosis.
Demographic, anthropometric, clinical, laboratory and histological patient data
Figure 1) Proportion of men and women in the control, nonalcoholic fatty liver disease (NAFLD) and hepatitis C virus (HCV)-positive patient groups. Steatosis due to NAFLD appears to be strikingly prevalent in men, as is steatosis associated with HCV infection. (more ...)
The prevalence of MS and related parameters in the three study groups is reported in . In general, the metabolic disorders are significantly more prevalent in patients with NAFLD than in those with HCV infection (). However, there was no significant difference between NAFLD and HCV patients in the prevalence of hyperglycemia (19.6% versus 17.5%), and there was a trend for a higher prevalence of hypertension in HCV patients (24% versus 16.9%).
Prevalence of metabolic syndrome and its components
The prevalence of fasting hyperglycemia (fasting glucose of 6.11 mmol/L or higher) in HCV patients (17.5%) was higher than in controls (6.7%), ranking in the same order of magnitude as NAFLD patients (19.6%). The prevalence of hypercholesterolemia and hypertriglyceridemia was significantly higher in patients with NAFLD than in those with HCV infection (59.8% versus 17.5%, respectively; P=0.001) (). Similarly, the prevalence of obesity (ie, BMI 30 kg/m2 or higher) was significantly higher in NAFLD patients than in those with HCV infection (34.4% versus 12.4%, respectively; P=0.001) (). Taken collectively, according to the ATP III modified criteria, the prevalence of MS was significantly higher in NAFLD than in HCV and in healthy controls (27.9% versus 4.1% versus 5.5%, respectively; P=0.001) ().
To assess the prevalence and independent predictors of IR, a logistic regression analysis was performed for NAFLD and HCV patients. A HOMA-IR value of greater than 2.6659, corresponding to the 75th percentile of the healthy controls value, was used as the dependent variable. All parameters evaluated in the patients and reported in were used as independent variables. Age, sex and BMI were entered into the statistical analysis as covariates. As reported in , the prevalence of IR in NAFLD patients was 70% and the independent factors associated were BMI and triglycerides (). The prevalence of IR in HCV-infected patients was 78.7% (). There was no difference in the prevalence of IR among HCV genotype 1 and 2. The univariate analysis for HCV-infected patients revealed that the variables associated with IR were steatosis extent, fibrosis stage, inflammatory grade and HCV viral load. With multivariate analysis, male sex and fibrosis stage were independently associated with IR in this series of HCV-infected patients (). These same variables predicted IR when the analysis was limited to patients with HCV and steatosis more than 5% alone (data not shown).
Prevalence and predictors of insulin resistance in nonalcoholic fatty liver disease
Prevalence and predictors of insulin resistance in hepatitis C-naive genotype 1 or 2