BACKGROUND & AIMS Controlled attenuation parameter (CAP) is a novel non-invasive measure of hepatic steatosis, but it has not been evaluated in alcoholic liver disease. Therefore, we aimed to validate CAP for the assessment of biopsy-verified alcoholic steatosis and to study the effect of alcohol detoxification on CAP. METHODS This was a cross-sectional biopsy-controlled diagnostic study in four European liver centres. Consecutive alcohol-overusing patients underwent concomitant CAP, regular ultrasound, and liver biopsy. In addition, we measured CAP before and after admission for detoxification in a separate single-centre cohort. RESULTS A total of 562 patients were included in the study: 269 patients in the diagnostic cohort with steatosis scores S0, S1, S2, and S3 = 77 (28%), 94 (35%), 64 (24%), and 34 (13%), respectively. CAP diagnosed any steatosis and moderate steatosis with fair accuracy (area under the receiver operating characteristic curve [AUC] ≥S1 = 0.77; 0.71-0.83 and AUC ≥S2 = 0.78; 0.72-0.83), and severe steatosis with good accuracy (AUC S3 = 0.82; 0.75-0.88). CAP was superior to bright liver echo pattern by regular ultrasound. CAP above 290 dB/m ruled in any steatosis with 88% specificity and 92% positive predictive value, while CAP below 220 dB/m ruled out steatosis with 90% sensitivity, but 62% negative predictive value. In the 293 patients who were admitted 6.3 days (interquartile range 4-6) for detoxification, CAP decreased by 32 ± 47 dB/m (p <0.001). Body mass index predicted higher CAP in both cohorts, irrespective of drinking pattern. Obese patients with body mass index ≥30 kg/m2 had a significantly higher CAP, which did not decrease significantly during detoxification. CONCLUSIONS CAP has a good diagnostic accuracy for diagnosing severe alcoholic liver steatosis and can be used to rule in any steatosis. In non-obese but not in obese, patients, CAP rapidly declines after alcohol withdrawal. LAY SUMMARY CAP is a new ultrasound-based technique for measuring fat content in the liver, but has never been tested for fatty liver caused by alcohol. Herein, we examined 562 patients in a multicentre setting. We show that CAP highly correlates with liver fat, and patients with a CAP value above 290 dB/m were highly likely to have more than 5% fat in their livers, determined by liver biopsy. CAP was also better than regular ultrasound for determining the severity of alcoholic fatty-liver disease. Finally, we show that three in four (non-obese) patients rapidly decrease in CAP after short-term alcohol withdrawal. In contrast, obese alcohol-overusing patients were more likely to have higher CAP values than lean patients, irrespective of drinking.

中文翻译：

---

受控衰减参数和酒精性肝脂肪变性：酒精解毒的诊断准确性和作用

背景和目的 受控衰减参数 (CAP) 是一种新型的非侵入性肝脂肪变性测量方法，但尚未在酒精性肝病中进行评估。因此，我们旨在验证 CAP 用于评估活检证实的酒精性脂肪变性，并研究酒精解毒对 CAP 的影响。方法 这是一项在四个欧洲肝脏中心进行的横断面活检控制的诊断研究。连续酗酒的患者接受了伴随的 CAP、定期超声和肝活检。此外，我们在一个单独的单中心队列中测量了入院前和入院后的 CAP。结果 研究共纳入 562 名患者：诊断队列中 269 名患者的脂肪变性评分为 S0、S1、S2 和 S3 = 77 (28%)、94 (35%)、64 (24%) 和 34 (13%)，分别。CAP 诊断任何脂肪变性和中度脂肪变性具有相当的准确性（受试者工作特征曲线下面积 [AUC] ≥S1 = 0.77；0.71-0.83 和 AUC ≥S2 = 0.78；0.72-0.83），以及具有良好准确性的严重脂肪变性 (AUC S3) = 0.82；0.75-0.88)。CAP 优于常规超声的明亮肝脏回声模式。CAP 高于 290 dB/m 以 88% 的特异性和 92% 的阳性预测值排除脂肪变性，而低于 220 dB/m 的 CAP 以 90% 的敏感性排除脂肪变性，但阴性预测值为 62%。在 6.3 天（四分位距 4-6）接受解毒治疗的 293 名患者中，CAP 降低了 32 ± 47 dB/m (p <0.001)。无论饮酒模式如何，体重指数都预测了两个队列中较高的 CAP。体重指数≥30 kg/m2 的肥胖患者的 CAP 显着升高，在解毒过程中没有明显减少。结论 CAP诊断重度酒精性肝脂肪变性具有良好的诊断准确性，可用于任何脂肪变性的诊断。在非肥胖但非肥胖患者中，酒精戒断后 CAP 迅速下降。LAY 总结 CAP 是一种新的基于超声的技术，用于测量肝脏中的脂肪含量，但从未针对酒精引起的脂肪肝进行过测试。在此，我们在多中心环境中检查了 562 名患者。我们表明 CAP 与肝脏脂肪高度相关，通过肝活检确定，CAP 值高于 290 dB/m 的患者很可能肝脏中脂肪含量超过 5%。在确定酒精性脂肪肝疾病的严重程度方面，CAP 也优于常规超声检查。最后，我们表明，四分之三（非肥胖）患者在短期戒酒后 CAP 迅速下降。相比之下，无论是否饮酒，肥胖过度饮酒的患者都比瘦弱的患者更有可能具有更高的 CAP 值。