The impact of fatigue on mortality of patients with non-alcoholic fatty liver disease: Data from National Health and nutrition examination survey 2005-2010 and 2017-2018.

Objective: Fatigue among patients with NAFLD may negatively impact their health-related quality of life and clinical outcomes (mortality). We determined fatigue prevalence and its association with all-cause mortality among patients with NAFLD.

Design: NHANES 2005-2010 and 2017-2018 data were used with linked mortality data. NAFLD was defined by fatty liver index for NHANES 2005-2010 and by transient elastography for NHANES 2017-2018. Fatigue was assessed by Patient Health Questionnaire.

Results: NHANES 2005-2010 cohort (n = 5429, mean age 47.1 years, 49.7% male, 69.9% white), 37.6% had NAFLD. Compared to non-NAFLD controls, fatigue was more common in NAFLD (8.35% vs 6.0%, p = .002). Among NHANES 2017-2018 cohort (n = 3830, mean age 48.3 years, 48.6% male, 62.3% white), 36.9% had NAFLD. Compared to non-NAFLD controls, fatigue was more common among NAFLD (8.7% vs 6.2%). NAFLD had more sleep disturbance (34.0% vs 26.7%), cardiovascular disease (CVD) (10.7% vs. 6.3%), significant hepatic fibrosis (liver stiffness>8.0 kPa, 17.9% vs 3.5%) and advanced hepatic fibrosis (>13.1 kPa, 5.4% vs 0.9%; all p < .003). The presence of depression (OR: 11.52, 95% CI: 4.45-29.80, p < .0001), CVD (OR: 3.41, 95% CI: 1.02-11.34, p = .0462) and sleep disturbance (OR: 2.00, 95% CI: 1.00-3.98, p = .0491) was independently associated with fatigue; good sleep quality (OR: 0.58, 95% CI: 0.35-0.96, p = .0366) had an inverse association. By multivariable Cox model, NAFLD adults with fatigue experienced 2.3-fold higher mortality than NAFLD without fatigue (HR: 2.31, 95% CI: 1.37-3.89, p = .002).

Conclusions: Fatigue among those with NAFLD is associated with increased risk for mortality and is mainly driven by depression, sleep disturbance and CVD. These findings have important clinical implications.