The Chronic Hepatitis B Liver Fibrosis Calculator (CHB-LFC) is intended for optimal application of non-invasive markers of liver fibrosis in patients with chronic hepatitis B (CHB). Unlike other commercial tests, this tool is based on free scores for non-invasive assessment of liver fibrosis, which have been validated in multiple studies and in a variety of liver diseases. We used our sample to optimize score thresholds in population of CHB patients and to select scores with the best cut-offs for diagnosis of presence or absence of significant liver fibrosis and cirrhosis. A combination algorithm of 4 separate scores (APRI, FIB-4, GUCI and Lok) was used for creation of this tool.
All threshold points were calculated from a sample of 211 Caucasian patients with chronic hepatitis B, with 56.4% prevalence of significant fibrosis and 14.7% prevalence of liver cirrhosis. The study was conducted at the Department of Gastroenterology and Hepatology University Clinical Center Tuzla, Bosnia and Herzegovina.
- In this sample, this clinical calculator allowed for potential avoidance of 58.3% liver biopsies with 93.5% of correctly classified patients (95%CI=97.2%-97.0%). In a sample of 1000 patients that would mean 583 saved biopsies with 38 misclassified patients.
- At the same time, for detection of liver cirrhosis, this clinical calculator was able to classify of 85.8% of patients with 97.5% accuracy for exclusion and 100% accuracy for detection of cirrhosis, and overall accuracy of 97.8% (95% CI=94.5%-99.1%).
These numbers make this online calculator a valuable and sufficiently precise tool for non-invasive assessment of liver fibrosis in CHB population in areas with limited resources where commercial (expensive) diagnostic modalities are not available.
Diagnostic accuracies of selected scores were as follows:
- APRI score at a threshold value of <0.5 has a sensitivity of 96.6%, negative predictive value of 93.5% and negative likelihood ratio of 0.06 for significant liver fibrosis (METAVIR F≥2).
- FIB-4 score at a threshold value of >1.45 has a specificity of 95.7%, positive predictive value of 93.4% and positive likelihood ratio of 11.02 for significant liver fibrosis.
- GUCI score (Goeteborg University Cirrhosis Index) at a threshold value <1.80 has a sensitivity of 85.1%, negative predictive value of 97.5% and negative likelihood ratio of 0.17 for liver cirrhosis (METAVIR F=4).
- Lok index at a threshold value >0.65 has a specificity of 100%, positive predictive value of 100% for liver cirrhosis.
The validation of accuracy and discriminative ability of algorithm in test sample and external validation sample of 65 patients is presented on the following table:
CHB-LFC is based on original formulas published in following papers:
- Wai CT, Greenson JK, Fontana RJ, et al. A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C. Hepatology 2003;38:518-26.
- Sterling RK, Lissen E, Clumeck N, et al. Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection. Hepatology 2006;43:1317-25.
- Islam S, Antonsson L, Westin J, et al. Cirrhosis in hepatitis C virus-infected patients can be excluded using an index of standard biochemical serum markers. Scandinavian journal of gastroenterology 2005;40:867.
- Lok AS, Ghany MG, Goodman ZD, et al. Predicting cirrhosis in patients with hepatitis C based on standard laboratory tests: results of the HALT-C cohort. Hepatology 2005;42:282-92.
For more details please refer to original publication describing the algorithm.
Salkic NN et al. Eur J Intern Med. 2012 doi: 10.1016/j.ejim.2015.07.005. Epub 2015 Jul 17.