Non-Alcoholic Fatty Liver Disease and Its Association with Kidney and Cardiovascular Outcomes in Moderate to Advanced Chronic Kidney Disease

Introduction: Non-alcoholic fatty liver disease (NAFLD) has emerged as a potential indicator for cardio-metabolic risk. However, clinical implications of NAFLD in patients with chronic kidney disease (CKD) are still elusive. We investigated to explore the association between NAFLD and adverse clinical outcomes among patients with CKD.

Methods: In this national population-based retrospective cohort study, we analyzed 816,857 individuals who underwent National Health Insurance Service health examinations and had an estimated glomerular filtration rate of 15-59 mL/min/1.73 m2. The main predictor was the fatty liver index (FLI), a surrogate marker for NAFLD. The primary outcome was a composite cardiovascular or kidney events, which were examined combined or separately.

Results: During a median follow-up of 7.7 (IQR, 6.4-9.6) years, the composite outcome events occurred in 74,266 (9.1%) individuals. Among these, there were 55,525 (6.8%) cardiovascular events and 22,961 (2.8%) kidney events, respectively. Compared to FLI of <30, the hazard ratio (HRs; 95% confidence intervals [CIs]) for the composite outcome were 1.16 (1.14-1.18) and 1.30 (1.26-1.33) for the FLIs of 30-59 and ≥60, respectively. The corresponding HRs for cardiovascular events were 1.21 (95% CI, 1.18-1.23) and 1.36 (95% CI, 1.31-1.40), respectively. Furthermore, FLIs of 30-59 and ≥60 were associated with an 11% (HR, 1.11; 95% CI, 1.07-1.15) and 24% (HR, 1.24; 95% CI, 1.17-1.30) increased risk of kidney events, respectively.

Conclusions: NAFLD was associated with higher risk of adverse clinical outcomes in individuals with CKD. These findings suggest that NAFLD, as assessed by the FLI, can serve as a predictor of cardiovascular and kidney events in CKD population.