The FibroTest value in discriminating between insignificant and significant fibrosis in chronic hepatitis C patients. The Romanian experience

Impact of contacting study authors to obtain additional data for systematic reviews: diagnostic accuracy studies for hepatic fibrosis

BACKGROUND

Seventeen of 172 included studies in a recent systematic review of blood tests for hepatic fibrosis or cirrhosis reported diagnostic accuracy results discordant from 2 × 2 tables, and 60 studies reported inadequate data to construct 2 × 2 tables. This study explores the yield of contacting authors of diagnostic accuracy studies and impact on the systematic review findings.

METHODS

Sixty-six corresponding authors were sent letters requesting additional information or clarification of data from 77 studies. Data received from the authors were synthesized with data included in the previous review, and diagnostic accuracy sensitivities, specificities, and positive and likelihood ratios were recalculated.

RESULTS

Of the 66 authors, 68% were successfully contacted and 42% provided additional data for 29 out of 77 studies (38%). All authors who provided data at all did so by the third emailed request (ten authors provided data after one request). Authors of more recent studies were more likely to be located and provide data compared to authors of older studies. The effects of requests for additional data on the conclusions regarding the utility of blood tests to identify patients with clinically significant fibrosis or cirrhosis were generally small for ten out of 12 tests. Additional data resulted in reclassification (using median likelihood ratio estimates) from less useful to moderately useful or vice versa for the remaining two blood tests and enabled the calculation of an estimate for a third blood test for which previously the data had been insufficient to do so. We did not identify a clear pattern for the directional impact of additional data on estimates of diagnostic accuracy.

CONCLUSIONS

We successfully contacted and received results from 42% of authors who provided data for 38% of included studies. Contacting authors of studies evaluating the diagnostic accuracy of serum biomarkers for hepatic fibrosis and cirrhosis in hepatitis C patients impacted conclusions regarding diagnostic utility for two blood tests and enabled the calculation of an estimate for a third blood test. Despite relatively extensive efforts, we were unable to obtain data to resolve discrepancies or complete 2 × 2 tables for 62% of studies.

Prediction of fibrosis in hepatitis C patients: assessment using hydroxyproline and oxidative stress biomarkers

This study aims to evaluate the diagnostic accuracy of aspartate aminotransferase (AST), alanine aminotransferase (ALT), hydroxyproline (Hyp), malondialdhyde (MDA), superoxide dismutase (SOD), and total antioxidant status (TAS) biomarkers in comparison with Metavir scoring for assessing the severity of hepatic fibrosis in the HCV patients. The histological activity index (HAI) was evaluated in liver biopsy by Metavir scoring system in 150 patients with HCV. HCV initial screening, further genotyping and biochemical data analysis were performed in serum using ELISA and biochemical assays. Out of the 150 HCV patients in this study, the most prevalent HCV genotype was genotype 4 (97 %). The significant fibrosis was estimated in 83.3 % of patients using the Metavir scoring system. They classified into 40 % of patients with mild fibrosis (F0-F1); 60 % with significant fibrosis (F2-4) and 20 % had cirrhosis (F4). Patients with cirrhosis (F4) showed significant correlation (P < 0.001) with increase in ALT, AST, AST/ALT, Hyp, Hyp/platelet count ratio, APRI, MDA, older age, and decrease (P < 0.001) in SOD, TAS, and platelet count compared to other stages of liver fibrosis. In our population, using optimized cut-off values of AST/ALT, APRI, Hyp, MDA, SOD, and TAS, significant fibrosis could be predicted accurately with a range of (80-90 %), and cirrhosis with a range of (67-97 %) of HCV patients. Our study showed that, oxidative stress and Hyp markers could be useful as noninvasive diagnostic markers in the assessment of hepatic fibrosis.

Pleiotropy and allelic heterogeneity in the TOMM40-APOE genomic region related to clinical and metabolic features of hepatitis C infection

Hepatitis C virus (HCV) modulates host lipid metabolism as part of its lifecycle and is dependent upon VLDL for co-assembly and secretion. HCV dyslipidemia is associated with steatosis, insulin resistance, IL28B genotype and disease progression. Apolipoprotein E (ApoE) is an important lipid transport protein, a key constituent of VLDL, and is involved in immunomodulation. Our aims were to determine the role of APOE regional polymorphisms on host lipids, IL28B genotype and disease severity in chronic HCV (CHC) patients. The study cohort included 732 CHC patients with available DNA for genotype determination of four polymorphisms in the chromosome 19 region that encompasses the TOMM40, APOE and APOC1 genes. Serum lipid analysis and apolipoproteins levels were measured using an immunoturbidimetric assay. APOE rs7412 polymorphism (capturing the ε2 isoform) was significantly associated with serum ApoE levels in both Caucasians and African-American patients (p = 2.3 × 10(-11)) and explained 7 % of variance in serum ApoE. Among IL28B-CC patients (n = 196), the rs429358 (defines ε4 isoform) and TOMM40 '523' S polymorphisms were associated with 12 % of variance in ApoB levels. Patients homozygous for the APOE ε3 isoform had a greater than twofold increased odds of F2-F4 fibrosis (p = 1.8 × 10(-5)), independent of serum lipid and lipoprotein levels. There were no associations between APOE polymorphisms and serum HDL-C, APO-CIII and triglycerides. In CHC patients, genetic heterogeneity in the APOE/TOMM40 genomic region is significantly associated with variation in serum ApoE and ApoB levels, and also with fibrosis suggesting a pleiotropic attribute of this genomic region.

Meta-analyses of FibroTest diagnostic value in chronic liver disease

BACKGROUND

FibroTest (FT) is a biomarker of liver fibrosis initially validated in patients with chronic hepatitis C (CHC). The aim was to test two hypotheses, one, that the FT diagnostic value was similar in the three other frequent fibrotic diseases: chronic hepatitis B (CHB), alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD); and the other, that the FT diagnostic value was similar for intermediate and extreme fibrosis stages.

METHODS

The main end points were the FT area under the ROC curves (AUROCs) for the diagnosis of bridging fibrosis (F2F3F4 vs. F0F1), standardized for the spectrum of fibrosis stages, and the comparison of FT AUROCs between adjacent stages. Two meta-analyses were performed: one combining all the published studies (random model), and one of an integrated data base combining individual data. Sensitivity analysis integrated the independency of authors, lenght of biopsy, prospective design, respect of procedures, comorbidities, and duration between biopsy and serum sampling.

RESULTS

A total of 30 studies were included which pooled 6,378 subjects with both FT and biopsy (3,501 HCV, 1,457 HBV, 267 NAFLD, 429 ALD, and 724 mixed). Individual data were analyzed in 3,282 patients. The mean standardized AUROC was 0.84 (95% CI, 0.83-0.86), without differences between causes of liver disease: HCV 0.85 (0.82-0.87), HBV 0.80 (0.77-0.84), NAFLD 0.84 (0.76-0.92), ALD 0.86 (0.80-0.92), mixed 0.85 (0.80-0.93). The AUROC for the diagnosis of the intermediate adjacent stages F2 vs. F1 (0.66; 0.63-0.68, n = 2,055) did not differ from that of the extreme stages F3 vs. F4 (0.69; 0.65-0.72, n = 817) or F1 vs. F0 (0.62; 0.59-0.65, n = 1788).

CONCLUSION

FibroTest is an effective alternative to biopsy in patients with chronic hepatitis C and B, ALD and NAFLD. The FT diagnostic value is similar for the diagnosis of intermediate and extreme fibrosis stages.