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Latent Class Analysis of Noninvasive Methods and Liver Biopsy in Chronic Hepatitis C: An Approach without a Gold Standard.

ABSTRACT: To evaluate the applicability of the Latent Class Analysis (LCA) and accuracy of transient elastography (TE), aspartate-to-platelet-ratio-index (APRI), enhanced liver fibrosis (ELF), and liver biopsy (LB) for liver fibrosis assessment in a model without a gold standard.Significant fibrosis was defined as TE ≥ 7.1 kPa, APRI ≥ 1.5, ELF ≥ 9.37, or LB METAVIR F ≥ 2. Cirrhosis was defined as TE ≥ 12.5 kPa, APRI ≥ 2.0, ELF ≥ 10.31, or LB as METAVIR F = 4.117 patients with chronic hepatitis C were included. In the LCA, for significant fibrosis the sensitivities and specificities (95% CI) were 0.92 (0.86-0.98) and 0.79 (0.72-0.86) for TE; 0.47 (0.40-0.54) and 0.99 (0.95-1.00) for APRI; 0.81 (0.74-0.88) and 0.78 (0.71-0.85) for ELF; and 0.86 (0.68-1.00) and 0.91 (0.79-1.00) for LB. For cirrhosis, the sensitivities and specificities were 0.92 (0.76-1.00) and 0.94 (0.91-0.97) for TE; 0.57 (0.37-0.77) and 0.97 (0.93-1.00) for APRI; 0.94 (0.84-1.00) and 0.88 (0.82-0.94) for ELF; and 0.30 (0.12-0.48) and 1.00 for LB.LCA was useful to evaluate accuracy of methods for liver fibrosis staging. Sensitivities and specificities of noninvasive methods were increased in LCA compared to the use of LB as the gold standard.

SUBMITTER: Fernandes FF

PROVIDER: S-EPMC5615978 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundIn Europe the principal definitive host for Echinococcus multilocularis, causing alveolar echinococcosis in humans, is the red fox (Vulpes vulpes). Obtaining reliable estimates of the prevalence of E. multilocularis and relevant risk factors for infection in foxes can be difficult if diagnostic tests with unknown test accuracies are used. Latent-class analysis can be used to obtain estimates of diagnostic test sensitivities and specificities in the absence of a perfect gold standard. Samples from 300 foxes in Switzerland were assessed by four different diagnostic tests including necropsy followed by sedimentation and counting technique (SCT), an egg-PCR, a monoclonal and a polyclonal copro-antigen ELISA. Information on sex, age and presence of other cestode species was assessed as potential covariates in the Bayesian latent class models. Different Bayesian latent-class models were run, considering dichotomized test results and, additionally, continuous readings resulting in empirical ROC curves.ResultsThe model without covariates estimated a true parasite prevalence of 59.5% (95% CI: 43.1-66.4%). SCT, assuming a specificity of 100%, performed best among the four tests with a sensitivity of 88.5% (95% CI: 82.7-93.4%). The egg-PCR showed a specificity of 93.4% (95% CI: 87.3-99.1%), although its sensitivity of 54.8% was found moderately low (95% CI: 48.5-61.0%). Relatively higher sensitivity (63.2%, 95% CI: 55.3-70.8%) and specificity (70.0%, 95% CI: 60.1-79.4%) were estimated for the monoclonal ELISA compared to the polyclonal ELISA with a sensitivity and specificity of 56.0% (95% CI: 48.0-63.9%) and 65.9% (95% CI: 55.8-75.6%), respectively. In the Bayesian models, adult foxes were found to be less likely infected than juveniles. Foxes with a concomitant cestode infection had double the odds of an E. multilocularis infection. ROC curves following a Bayesian approach enabled the empirical determination of the best cut-off point. While varying the cut-offs of both ELISAs, sensitivity and specificity of the egg-PCR and SCT remained constant in the Bayesian latent class models.ConclusionsAdoption of a Bayesian latent class approach helps to overcome the absence of a perfectly accurate diagnostic test and gives a more reliable indication of the test performance and the impact of covariates on the prevalence adjusted for diagnostic uncertainty.

Project description:BackgroundThe diagnosis of canine echinococcosis can be a challenge in surveillance studies because there is no perfect gold standard that can be used routinely. However, unknown test specificities and sensitivities can be overcome using latent-class analysis with appropriate data.MethodologyWe utilised a set of faecal and purge samples used previously to explore the epidemiology of canine echinococcosis on the Tibetan plateau. Previously only the purge results were reported and analysed in a largely deterministic way. In the present study, additional diagnostic tests of copro-PCR and copro-antigen ELISA were undertaken on the faecal samples. This enabled a Bayesian analysis in a latent-class model to examine the diagnostic performance of a genus specific copro-antigen ELISA, species-specific copro-PCR and arecoline purgation. Potential covariates including co-infection with Taenia, age and sex of the dog were also explored. The dependence structure of these diagnostic tests could also be analysed.Principle findingsThe most parsimonious result, indicated by deviance-information criteria, suggested that co-infection with Taenia spp. was a significant covariate with the Echinococcus infection. The copro-PCRs had estimated sensitivities of 89% and 84% respectively for the diagnoses of Echinococcus multilocularis and E. granulosus. The specificities for the copro-PCR were estimated at 93 and 83% respectively. Copro-antigen ELISA had sensitivities of 55 and 57% for the diagnosis of E. multilocularis and E. granulosus and specificities of 71 and 69% respectively. Arecoline purgation with an assumed specificity of 100% had estimated sensitivities of 76% and 85% respectively.SignificanceThis study also shows that incorporating diagnostic uncertainty, in other words assuming no perfect gold standard, and including potential covariates like sex or Taenia co-infection into the epidemiological analysis may give different results than if the diagnosis of infection status is assumed to be deterministic and this approach should therefore be used whenever possible.

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Latent Class Analysis of Noninvasive Methods and Liver Biopsy in Chronic Hepatitis C: An Approach without a Gold Standard.

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