Hepatic Steatosis in Lean Patients: Risk Factors and Impact on Mortality.

Background: The prognostic impact of liver steatosis in obese patients is well established. Limited data on the risk factors for and impact of hepatic steatosis in lean patients are available.
Aims: Assess risk factors for liver steatosis in lean patients and investigate its impact on survival.
Methods: Patients without viral hepatitis and with a BMI ≤ 25 kg/m ² undergoing liver stiffness measurement (LSM) and controlled attenuation parameter (CAP) by transient elastography were retrospectively identified. Clinical characteristics and laboratory test results were obtained at the time of LSM/CAP measurement. National death registry data were obtained in order to assess survival.
Results: Among n = 218 lean patients, n = 97 (34.5%) showed significant liver steatosis (CAP ≥ 268 dB/m), while n = 184 (65.5%) had no or just mild steatosis (CAP < 268 dB/m). Patients with steatosis had higher GGT (238.0(± 450.3) vs. 112.1(± 180.0) IU/mL; p = 0.013), AST (63(± 67.4) vs. 38.5(± 32.9) IU/mL; p = 0.001), ALT (59.1(± 58.8) vs. 44.3(± 52.7) IU/mL; p = 0.048) and triglyceride levels (120.1(± 80.3) vs. 96.1(± 58.2) mg/dL; p = 0.014), and showed a trend toward more severe fibrosis (LSM 15.6(± 19.5) vs. 12.0(± 15.7) kPa; p = 0.115). In multivariate binary logistic regression analysis, only serum uric acid levels were independently associated with liver steatosis (odds ratio 1.43 per unit mg/dL; 95% CI 1.001-2.054; p = 0.049). During a mean follow-up of 38.9(± 10.6) months, n = 14 patients (5.0%) died. In the absence of advanced fibrosis, survival after 1 year was similar in patients without (98.7%) and with (98.6%) significant steatosis. Patients with advanced fibrosis had worse 1-year survival without concomitant significant steatosis (84.8%) than patients with steatosis (95.8%; log-rank p < 0.001).
Conclusions: High serum uric acid levels increase the risk of liver steatosis in lean patients. Liver fibrosis but not hepatic steatosis is a risk factor for impaired survival in lean patients.