Nonalcoholic fatty liver disease in chronic obstructive pulmonary disease

Abstract

Nonalcoholic fatty liver disease (NAFLD) is independently linked to cardiometabolic morbidity and mortality. Low-grade inflammation, oxidative stress and ectopic fat, common features of chronic obstructive pulmonary disease (COPD), might contribute to the development of NAFLD.We aimed to investigate the prevalence of NAFLD and to evaluate the relationship between various types of liver damage and COPD severity, comorbidities and circulating inflammatory cytokines. Validated noninvasive tests (FibroMax: SteatoTest, NashTest and FibroTest) were used to assess steatosis, nonalcoholic steatohepatitis (NASH) and liver fibrosis. Patients underwent an objective assessment of COPD comorbidities, including sleep studies. Biological parameters included a complete lipid profile and inflammatory markers.In COPD patients the prevalence of steatosis, NASH and fibrosis were 41.4%, 36.9% and 61.3%, respectively. In multivariate analysis, SteatoTest and FibroTest were significantly associated with sex, body mass index (BMI), untreated sleep apnoea and insulin resistance, and, in addition, COPD Global Initiative for Chronic Obstructive Lung Disease stage for SteatoTest. Patients with steatosis had higher tumour necrosis factor-α levels and those with NASH or a combination of liver damage types had raised leptin levels after adjustment for age, sex and BMI.We concluded that NAFLD is highly prevalent in COPD and might contribute to cardiometabolic comorbidities.