Background

Non-alcoholic fatty liver disease (NAFLD) is known to be an independent risk factor for poor health outcome. The fatty liver index (FLI), which is an algorithm based on waist circumference, body mass index (BMI), triglyceride, and gamma-glutamyl transferase (GGT), was initially developed to detect fatty liver and is currently being used in epidemiological studies and screening as an alternative to ultrasonography. Our study aims to investigate whether FLI correlates with the occurrence of cardiovascular disease (CVD) and mortality risks.

Methods

This retrograde cohort study using National Health Insurance Service (NHIS) data of South Korea included 3,011,588 people. The FLI was calculated with the values achieved from the health screenings from 2009 to 2011 and divided into quartiles. Then, the all-cause mortality and risks of myocardial infarction and stroke were assessed and compared among quartile groups from 2014 to 2017.

Results

There were 52,320 deaths (1.74%), 17,753 cases of MI (0.59%), and 23,506 cases of stroke (0.78%) during the median follow-up of 5 years. There was a linear association between higher FLI values and outcome measures. In the multivariable adjusted model, the hazard ratios (95% confidence intervals) comparing the highest vs. lowest quartiles of FLI were 1.37 (1.32–1.42) for all-cause mortality, 2.14 (2.0-2.28) for MI, and 2.0 (1.89-2.11) for stroke, respectively. The results were similar when we performed stratified analysis by age, sex, presence or absence of obesity, diabetes and hypertension.

Conclusions

FLI is independently associated with cardiovascular disease and all-cause mortality.Our finding indicates that FLI, a surrogate marker of NAFLD, has a prognostic value for detecting individuals for higher risk of CVD and mortality. Furthermore, it strongly supports the evidences of a strong link between NAFLD and poor health outcome in Asian population