Controlled attenuation parameter and alcoholic hepatic steatosis: Diagnostic accuracy and role of alcohol detoxification

J Hepatol. 2018 May;68(5):1025-1032. doi: 10.1016/j.jhep.2017.12.029. Epub 2018 Jan 16.


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.

Keywords: Alcohol detoxification; Alcoholic liver disease; Controlled attenuation parameter; Diagnostic test; Fatty liver; FibroScan; Non-invasive; Sensitivity; Specificity; Steatohepatitis.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alcohol Abstinence*
  • Alcoholism / diagnostic imaging
  • Biopsy
  • Cohort Studies
  • Cross-Sectional Studies
  • Elasticity Imaging Techniques
  • Fatty Liver, Alcoholic / diagnostic imaging*
  • Fatty Liver, Alcoholic / therapy*
  • Female
  • Humans
  • Liver / diagnostic imaging
  • Male
  • Metabolic Syndrome / diagnostic imaging
  • Middle Aged
  • Predictive Value of Tests
  • Risk Factors
  • Ultrasonography / methods*