A Prospective Study of Fatty Liver Index and Incident Hypertension: The KoGES-ARIRANG Study

Background
Although non-alcoholic fatty liver disease is the hepatic manifestation of metabolic syndrome, its influence on hypertension development is poorly understood. We investigated whether fatty liver disease, as assessed by the fatty liver index, could predict the development of hypertension independently of systemic insulin resistance, inflammatory status and adipokine levels.
Methods
Prospective cohort study of 1,521 adults (484 men and 1037 women) aged 40 to 70 years without baseline hypertension examined. An equation was used to calculate fatty liver index and classify patients as follows: fatty liver index <30, no non-alcoholic fatty liver disease; fatty liver index ≥60, non-alcoholic fatty liver disease; and 30≤ fatty liver index <60, intermediate fatty liver index.
Results
During an average of 2.6 years of follow-up, 153 subjects (10.06%) developed hypertension. Fatty liver index was positively associated with baseline blood pressure, homeostasis model assessment of insulin resistance, urinary albumin/creatinine excretion, and high sensitivity C-reactive protein. After adjustment for confounding factors, including markers of insulin resistance, systemic inflammation and adiponectin levels, the odds ratio [95% confidence interval] for the incident hypertension increased in a graded manner with fatty liver index (<30 vs. 30–59 vs. ≥60 = 1 vs. 1.83 [1.16~2.88] vs. 2.09 [1.08~4.055], respectively).
Conclusions
Non-alcoholic fatty liver disease assessed by fatty liver index was an independent risk factor for hypertension. Our findings suggest that fatty liver index, a simple surrogate indicator of fatty liver disease, might be useful for identifying subjects at high risk for incident hypertension in clinical practice.

背景
尽管非酒精性脂肪性肝病（non-alcoholic fatty liver disease）是代谢综合征（metabolic syndrome）的肝脏受累表现，但其对高血压发生发展的影响目前仍未得到充分阐明。本研究旨在探讨通过脂肪肝指数（fatty liver index）评估的非酒精性脂肪性肝病，能否在不考虑全身胰岛素抵抗（systemic insulin resistance）、炎症状态（inflammatory status）及脂肪因子水平的前提下，独立预测高血压的发生风险。
方法
本研究为前瞻性队列研究，共纳入1521名年龄40~70岁、经筛查无基线高血压的成年人（其中男性484名，女性1037名）。通过预设公式计算脂肪肝指数，并按如下标准对受试者进行分组：脂肪肝指数<30者判定为无脂肪肝；脂肪肝指数≥60者判定为非酒精性脂肪性肝病；30≤脂肪肝指数<60者判定为中间型脂肪肝指数组。
结果
平均随访2.6年期间，共有153名受试者（占比10.06%）新发高血压。脂肪肝指数与基线血压、胰岛素抵抗稳态模型评估（homeostasis model assessment of insulin resistance）指标、尿白蛋白/肌酐排泄率及高敏C反应蛋白（high sensitivity C-reactive protein）水平呈正相关。在校正包括胰岛素抵抗标志物、全身炎症指标及脂联素水平在内的混杂因素后，新发高血压的比值比（odds ratio）与95%置信区间（95% confidence interval）随脂肪肝指数升高呈梯度升高：脂肪肝指数<30组、30~59组及≥60组的比值比分别为1、1.83[1.16~2.88]及2.09[1.08~4.055]。
结论
通过脂肪肝指数评估的非酒精性脂肪性肝病是高血压发生的独立危险因素。本研究结果提示，作为一种简便的非酒精性脂肪性肝病替代评估指标，脂肪肝指数或可用于临床实践中筛查新发高血压高风险人群。