Imperiale T F, Said A T, Cummings O W, Born L J
Department of Medicine, Indiana University School of Medicine and the Roudebush VA Medical Center, Indianapolis, USA.
Am J Gastroenterol. 2000 Sep;95(9):2328-32. doi: 10.1111/j.1572-0241.2000.02322.x.
A value of > or = 1 for the ratio of aspartate amino-transferase to alanine aminotransferase (the AST/ALT ratio or AAR) has been shown to have a positive predictive value of 100% for the diagnosis of cirrhosis in patients with chronic hepatitis C. If validated on separate cohorts, an AAR > or = 1 might obviate the need for liver biopsy in some patients with hepatitis C.
We attempted to validate the AAR by abstracting demographic and clinical data from a database of consecutive patients with hepatitis C who had a liver biopsy between 1993 and 1998. We used definitions, methods of data collection, and analyses comparable to those of the published study. A hepatopathologist blindly reviewed 49 liver biopsies for histological grade and stage.
The current cohort of 177 patients and the previous cohort of 139 patients were comparable in mean age (42.3 vs 43.8 yr), percentage of men (63 vs 67), percentage with an AAR > or =1 (20 vs 17), and Child-Pugh distribution, but differed in substantial use of ethanol (11% vs 3.6%; p = 0.01) and in the prevalence of cirrhosis (23% vs 34%, p = 0.06). Respective sensitivities of the AAR were 56% and 53%. An AAR > or =1 had a positive predictive value of 64% (95% confidence interval 48-78%) for the current cohort. Thirteen of 36 patients (36%) with an AAR > or =1 were incorrectly identified as having cirrhosis. Of these 13 patients, 6 had a normal AST and ALT, 5 had a minimally elevated AST or ALT, and 1 had advanced fibrosis without cirrhosis.
These results suggest that an AAR > or =1 may not be as useful for predicting cirrhosis in chronic hepatitis C as previously thought, and emphasizes the need for validation of clinical decision aids on independent patient cohorts.
天冬氨酸氨基转移酶与丙氨酸氨基转移酶比值（AST/ALT 比值或 AAR）≥1 已被证明对慢性丙型肝炎患者肝硬化的诊断具有 100%的阳性预测值。如果在不同队列中得到验证，AAR≥1 可能会使一些丙型肝炎患者无需进行肝活检。
我们试图通过从 1993 年至 1998 年期间接受肝活检的连续丙型肝炎患者数据库中提取人口统计学和临床数据来验证 AAR。我们使用的定义、数据收集方法和分析与已发表研究中的方法类似。一位肝脏病理学家对 49 份肝活检标本进行了组织学分级和分期的盲法评估。
当前的 177 例患者队列与之前的 139 例患者队列在平均年龄（42.3 岁对 43.8 岁）、男性百分比（63%对 67%）、AAR≥1 的百分比（20%对 17%）以及 Child-Pugh 分级分布方面具有可比性，但在乙醇大量使用情况（11%对 3.6%；p = 0.01）和肝硬化患病率（23%对 34%，p = 0.06）方面存在差异。AAR 的各自敏感性分别为 56%和 53%。对于当前队列，AAR≥1 的阳性预测值为 64%（95%置信区间 48 - 78%）。36 例 AAR≥1 的患者中有 13 例（36%）被错误地判定为患有肝硬化。在这 13 例患者中，6 例 AST 和 ALT 正常，5 例 AST 或 ALT 轻度升高，1 例有晚期纤维化但无肝硬化。
这些结果表明，AAR≥1 对预测慢性丙型肝炎肝硬化的作用可能不如先前认为的那样有用，并强调了在独立患者队列中验证临床决策辅助工具的必要性。
