Background & Aims

Tools have been developed to determine risk for nonalcoholic fatty liver disease (NAFLD) based on imaging, which does not always detect early-grade hepatic steatosis. We aimed to develop a tool to identify patients with NAFLD using ¹H MR spectroscopy (MRS).

Methods

We collected data from the Dallas Heart Study—a multiethnic, population-based, probability study of adults (18–65 y) that comprised an in-home medical survey; collection of fasting blood samples; MRS images to measure cardiac mass/function, abdominal subcutaneous/visceral adiposity; and quantification of hepatic triglyceride concentration, from 2000 through 2009. NAFLD were defined as 5.5% or more liver fat and we excluded patients with more than moderate alcohol use; 737 patients were included in the final analysis. We performed binary multivariable logistic regression analysis to develop a tool to identify patients with NAFLD and evaluate interactions among variables. We performed an internal validation analysis using 10-fold cross validation.

Results

We developed the Dallas Steatosis Index (DSI) to identify patients with NAFLD based on level of alanine aminotransferase, body mass index, age, sex, levels of triglycerides and glucose, diabetes, hypertension, and ethnicity. The DSI discriminated between patients with vs without NAFLD with a C-statistic of 0.824. The DSI outperformed 4 risk analysis tools, based on net reclassification improvement and decision curve analysis.

Conclusions

We developed an index, called the DSI, which accurately identifies patients with NAFLD based on MRS data. The DSI requires external validation, but might be used in development NAFLD screening programs, in monitoring progression of hepatic steatosis, and in epidemiology studies.

中文翻译：

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达拉斯脂肪变性指数可识别非酒精性脂肪肝患者。

背景与目标

已经开发出基于影像学确定非酒精性脂肪性肝病 (NAFLD) 风险的工具，但影像学并不总能检测到早期肝脂肪变性。我们旨在开发一种使用¹ H MR 光谱 (MRS) 识别 NAFLD 患者的工具。

方法

我们从达拉斯心脏研究中收集数据——一项针对成年人（18-65 岁）的多种族、基于人群的概率研究，其中包括一项家庭医学调查；空腹血样采集；用于测量心脏质量/功能、腹部皮下/内脏肥胖的 MRS 图像；从 2000 年到 2009 年，肝脏甘油三酯浓度的量化。NAFLD 被定义为 5.5% 或更多的肝脏脂肪，我们排除了饮酒超过中度的患者；737 名患者被纳入最终分析。我们进行了二元多变量逻辑回归分析，以开发一种工具来识别 NAFLD 患者并评估变量之间的相互作用。我们使用 10 倍交叉验证进行了内部验证分析。

结果

我们开发了达拉斯脂肪变性指数 (DSI)，以根据丙氨酸氨基转移酶水平、体重指数、年龄、性别、甘油三酯和葡萄糖水平、糖尿病、高血压和种族来识别 NAFLD 患者。DSI 区分 NAFLD 患者与非 NAFLD 患者的 C 统计量为 0.824。基于净重分类改进和决策曲线分析，DSI 优于 4 种风险分析工具。

结论

我们开发了一个名为 DSI 的指数，它可以根据 MRS 数据准确识别 NAFLD 患者。DSI 需要外部验证，但可用于开发 NAFLD 筛查项目、监测肝脂肪变性的进展以及流行病学研究。