Noninvasive ABDA Score Predicts Fibrotic NASH

Nikhil Tandon, MD, PhD

Credit: Indian Primary Health Care Support Initiative

The ABDA score, a composite score of alanine aminotransferase (ALT), BMI, diabetes, and age, may be a viable tool for predicting fibrotic nonalcoholic steatohepatitis (NASH), according to findings from a recent study.

The noninvasive predictive model was developed based on parameters found to be significantly associated factors of fibrotic NASH in multivariable analysis and validated in a cohort of asymptomatic individuals.

“The community prevalence of fibrotic NASH is difficult to estimate because of the limitations in obtaining a liver biopsy in asymptomatic individuals in the community. This subgroup of subjects warrants therapeutic interventions and should, therefore, be identified early,” wrote investigators.¹ “Subjects with fibrotic NASH have significantly higher metabolic risk factors, and early identification of this subgroup can prevent future cardiovascular and hepatic complications.”

Currently, a liver biopsy is the only way to diagnose fatty liver disease. Fat, inflammation, and liver damage observed during a liver biopsy are indicative of NASH.² Imaging-based techniques are sometimes used as noninvasive alternatives, but they are not as effective as a biopsy.³

To develop an identification model to evaluate fibrotic NASH community prevalence in asymptomatic individuals, senior investigator Nikhil Tandon, MD, PhD, head of the department of endocrinology and metabolism at the All India Institute of Medical Sciences, and a team of investigators conducted a retrospective analysis of 2 prospectively maintained databases. Participants included consecutive asymptomatic patients aged 30–60 years residing in North India between March 2017 and February 2020. Patients were excluded from analysis if they had significant alcohol consumption, a previous history of cirrhosis, hepatocellular carcinoma, hepatitis B and C infection, or were pregnant or bedridden.¹

In total, 1660 patients were included in the derivation cohort, comprised of 828 urban patients randomly selected from the ongoing Centre for Cardiac Risk Reduction in South Asia study and 832 rural patients randomly selected from an ongoing study by the Indian Council of Medical Research. The median age was 45 (interquartile range [IQR], 39 to 52) years, and 705 (42.5%) subjects were male. Diabetes, hypertension and metabolic syndrome were present in 372 (22.4%), 483 (29.1%) and 1100 (66.3%) patients, respectively. The median liver stiffness measure, controlled attenuation potential, and aspartate aminotransferase values were 4.6 kPa, 268 dB/m and 27 IU/L, respectively. Among the 1660 patients in the cohort, 45 (2.7%) had fibrotic NASH, with significantly higher prevalence in the urban cohort (4.6%) compared to the rural cohort (0.8%, P < .001).¹

Investigators also recruited 357 prospectively screened consecutive asymptomatic family members of patients with nonalcoholic fatty liver disease (NAFLD) evaluated at a tertiary care hospital in New Delhi for a validation cohort. The median age was 33 years (IQR, 22 to 45), 196 (54.9%) were male, and 42 (11.8%), 85 (25.2%) and 158 (44.3%) patients had diabetes, hypertension and metabolic syndrome, respectively. NAFLD was present in 204 (57.3%) patients and fibrotic NASH was present in 21 (5.9%) patients.¹

Investigators identified factors associated with fibrotic NASH using a stepwise multivariable logistic regression procedure. Variables were considered for model building based on their association at the level of significance up to P = .25 under a crude association analysis or their clinical relevance. The performance of the model was assessed using measures of calibration, discrimination, and clinical usefulness. Investigators also assessed discrimination ability in the validation cohort and used the DeLong test to compare the model's performance to NFS, BARD, and FIB-4 by comparing their AUC.¹

Investigators noted diabetes (odds ratio [OR] 4.09; 95% confidence interval [CI] 1.87 to 8.92; P < .001), BMI (OR, 1.15; 95% CI, 1.07 to 1.24; P < .001), ALT (OR, 38.47; 95% CI, 17.08 to 86.63; P < .001), and age (OR, 1.05; 95% CI, 1.00 to 1.10; P = .034) were significantly associated with fibrotic NASH in multivariable analysis. A predictive model was developed based on these 4 parameters and showed an AUC of 0.952 in the derivation cohort (95% CI, 0.921 to 0.983), identifying 88.9% of individuals with fibrotic NASH in the derivation cohort. At the cut-off of ≥-3.52, the ABDA score had an 88.9% sensitivity value, 88.3% specificity value, and 88.3% correctly classified value.¹

The model was also tested in the validation cohort, where it showed an AUC of 0.948 (95% CI, 0.918 to 0.977) and identified 81.0% of patients with fibrotic NASH at a cutoff of −3.52. Investigators pointed out there were no differences in the diagnostic performance of the developed model on validation data compared to the derivation cohort (P = .85).¹

The ABDA score was compared to other noninvasive scores for fibrosis in the validation cohort. The median NFS, BARD and FIB-4 scores were −2.49 (−3.46 to −1.34), 2.0 (1.0 to 2.0) and 0.81 (0.49 to 1.30), respectively. The AUC for the NFS, BARD and FIB-4 score in predicting fibrotic NASH was 0.642 (0.510 to 0.774), 0.501 (0.357 to 0.645) and 0.726 (0.617 to 0.835), respectively.¹

“The use of this score can aid clinicians identify subjects with fibrotic NASH in the community using easily available anthropometric and laboratory investigations. The ABDA score can be used as a screening tool to identify subjects with fibrotic NASH in the community, thereby, identifying those asymptomatic subjects who have the most advanced disease and need therapeutic interventions,” concluded investigators.¹

References:

1. Anand A, Shalimar, Arora U, et al. ABDA Score: A Non-invasive Model to Identify Subjects with Fibrotic Non-alcoholic Steatohepatitis in the Community. Journal of Clinical and Experimental Hepatology. 13(5). https://doi.org/10.1016/j.jceh.2023.03.008
2. Johns Hopkins Medicine. Nonalcoholic Fatty Liver Disease. Conditions and Diseases. Accessed September 14, 2023.  https://www.hopkinsmedicine.org/health/conditions-and-diseases/nonalcoholic-fatty-liver-disease
3. Nash Education Program. How is NASH diagnosed? What is NASH? Accessed September 14, 2023. https://www.the-nash-education-program.com/what-is-nash/how-is-nash-diagnosed/