Hepatitis C virus and lichen planus: a reciprocal association determined by a meta-analysis.

To explore the association between hepatitis C virus (HCV) and lichen planus (LP) by performing a meta-analysis of observational studies of the association. Data Sources Bibliographical searches were conducted in the MEDLINE, EMBASE, and China National Knowledge Infrastructure (CNKI) databases without any language limitations. Study Selection Studies were selected when the following criteria were met: the coexistence of a study group and a control group, the reliable and nonselective use of the reference standards for the diagnosis of LP and HCV, and the proportion of events (the prevalence of HCV in patients with LP or the prevalence of LP in patients with HCV). Data Extraction Three investigators independently assessed abstracts for relevant studies, and 2 investigators independently reviewed all eligible studies. Data Synthesis Sixty-three articles entailing 7 studies were included in the meta-analysis. For the primary outcome of prevalence of events, the meta-analysis showed that there existed an important association between HCV and LP. In the comparison of the prevalence of HCV exposure among patients with LP with that of control participants, the odds ratio (OR) was 5.4 (95% confidence interval [CI], 3.5-8.3); in the prevalence of LP among patients with HCV compared with the prevalence among control participants, the OR was 2.5 (95% CI, 2.0-3.1). The subgroup analyses with geographical stratification did not show a significant association in studies from South Asia (P = .21), Africa (P = .15), and North America (P = .09), and the subgroup analyses from stratification by LP type also did not show a significant association in the isolated cutaneous type (P = .17). When strict criteria were applied, the results of sensitivity analysis remained robust. Conclusion Hepatitis C virus infection is associated with a statistically significant risk for development of LP, suggesting that the presence of either HCV or certain types of LP may be used as a predictive marker of the other in certain geographical regions.