Increased prevalence of fatty liver in arterial hypertensive patients with normal liver enzymes: role of insulin resistance

Abstract

Background: The conditions associated with fatty liver disease presenting with normal liver enzymes and the mechanism involved in its development remain to be fully elucidated.

Aims: The aim of the present study was to test the hypothesis that fatty liver with normal liver enzymes occurs more frequently in arterial hypertensive patients and to establish whether this condition is associated with insulin resistance.

Patients: A total of 55 non-obese, non-diabetic, non-heavy alcohol drinking patients with arterial hypertensive and normal liver enzymes and 55 sex and age matched healthy subjects were enrolled into the study.

Methods: Plasma metabolic parameters, body mass index, and the presence of fatty liver were investigated. Insulin resistance was estimated from plasma insulin and glucose as the homeostasis model assessment index. Stepwise logistic regression and multivariate regression analysis were used on the combined sample to identify variables independently associated with fatty liver and insulin resistance.

Results: Hypertensive patients had a significantly higher prevalence of fatty liver (30.9% v 12.7%; p<0.041), higher insulin resistance (mean 2.27 (SD 1.81) v 1.56 (0.70); p = 0.022), and slightly higher body mass index (24.9 (3.0) v 24.0 (2.2); p = 0.043) than controls. Multivariate logistic regression identified insulin resistance (odds ratio 1.66 (95% confidence interval (CI) 1.03-2.52)) and body mass index (OR 1.22 (95% CI 1.00-1.49)) as factors independently associated with fatty liver. Multivariate regression analysis showed insulin resistance to be predicted by alanine transaminase (p = 0.002), presence of arterial hypertension (p = 0.029), and body mass index (p = 0.048).

Conclusion: The higher prevalence of non-alcoholic fatty liver in non-obese hypertensive patients with normal liver enzymes appears to be related to increases in insulin resistance and body weight.

Figure 1

Homeostasis model assessment index (HOMA), an indicator of insulin resistance. Values are mean (SD) in hypertensive (Hypert) patients and control subjects subgrouped according to presence or absence of fatty liver. p values indicate significance level of differences between subjects with and without fatty liver in hypertensive patients and in controls, as calculated using the unpaired t test.