Objective: To quantify fatigue in NAFLD, to determine whether perceived fatigue reflects impairment of physical function and to explore potential causes.
Design: Cohort study.
Setting: Regional Liver Unit /Teaching Hospital.
Patients: 156 consecutive patients with histologically proven NAFLD studied in 2 cohorts.
Main outcome measures: Phase 1: Perceived fatigue experienced by NAFLD patients (assessed using the fatigue impact scale (FIS)) in comparison to normal and liver disease controls, and relationship physical function (Actigraphy). Phase 2: Biological associations of fatigue in NAFLD were explored.
Results: Fatigue was markedly higher in NAFLD patients than in controls (mean FIS 51 ± 38 v 8 ± 12, p<0.0001). NAFLD patients showed significantly lower physical activity over 6 days (7089 ± 2909 mean steps/day v 8676 ± 2894, p=0.02). Significant inverse correlation was seen between FIS and physical activity (r2= 0.1, p=0.02). Fatigue experienced by NAFLD patients was similar to that in Primary Biliary Cirrhosis (n=36) (FIS 64 ± 9 v 61 ± 2, p=ns). No association was seen between FIS and biochemical and histological markers of liver disease severity.or insulin resistance (HOMA) (r2 <0.005). Significant association was seen between fatigue severity and daytime somnolence (Epworth Sleepiness Scale) (r2=0.2, p<0.0001).
Conclusion: Fatigue is a significant problem in NAFLD, is similar in degree to that in PBC patients and reflects a true impairment in physical function. Fatigue in NAFLD appears to be unrelated to either severity of underlying liver disease or insulin resistance but is associated with significant daytime somnolence.
- Excessive Daytime Sleepiness
- Non-alcoholic Fatty Liver Disease
- Quality of life