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Meta-Analysis
. 2013 Mar;37(5):527-36.
doi: 10.1111/apt.12199. Epub 2013 Jan 7.

Meta-analysis: The diagnostic accuracy of critical flicker frequency in minimal hepatic encephalopathy

F J Torlot  1 , M J W McPhail, S D Taylor-Robinson
Affiliations
Free PMC article
Meta-Analysis

Meta-analysis: The diagnostic accuracy of critical flicker frequency in minimal hepatic encephalopathy

F J Torlot et al. Aliment Pharmacol Ther. 2013 Mar.
Free PMC article

Abstract

Background: Minimal hepatic encephalopathy (MHE) reduces quality of life, increases the risk of road traffic incidents and predicts progression to overt hepatic encephalopathy and death. Current psychometry-based diagnostic methods are effective, but time-consuming and a universal 'gold standard' test has yet to be agreed upon. Critical Flicker Frequency (CFF) is a proposed language-independent diagnostic tool for MHE, but its accuracy has yet to be confirmed.

Aim: To assess the diagnostic accuracy of CFF for MHE by performing a systematic review and meta-analysis of all studies, which report on the diagnostic accuracy of this test.

Methods: A systematic literature search was performed to locate all publications reporting on the diagnostic accuracy of CFF for MHE. Data were extracted from 2 × 2 tables or calculated from reported accuracy data. Collated data were meta-analysed for sensitivity, specificity, diagnostic odds ratio (DOR) and summary receiver operator curve (sROC) analysis. Prespecified subgroup analysis and meta-regression were also performed.

Results: Nine studies with data for 622 patients were included. Summary sensitivity was 61% (95% CI: 55-67), specificity 79% (95% CI: 75-83) and DOR 10.9 (95% CI: 4.2-28.3). A symmetrical sROC gave an area under the receiver operator curve of 0.84 (SE = 0.06). The heterogeneity of the DOR was 74%.

Conclusions: Critical Flicker Frequency has a high specificity and moderate sensitivity for diagnosing minimal hepatic encephalopathy. Given the advantages of language independence and being both simple to perform and interpret, we suggest the use of critical flicker frequency as an adjunct (but not replacement) to psychometric testing.

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Figures

Figure 1
Figure 1
Flow diagram of studies identified in the systematic review.
Figure 2
Figure 2
Forest plots for sensitivity and specificity for all nine studies.
Figure 3
Figure 3
Symmetrical Summary Receiver Operator Curve (sROC) for all nine studies.
Figure 4
Figure 4
Deeks' funnel plot.
See this image and copyright information in PMC

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