The magnitude of the association between hepatitis C virus infection and oral lichen planus: meta-analysis and case control study.

Although hepatitis C virus (HCV) infection is associated with oral lichen planus (OLP), a case-control study and a meta-analysis were designed to investigate the magnitude of such an association. A total of 413 presumptive OLP patients (18-75 years) who referred to a dental clinic in Rasht (Iran) were consecutively selected. OLP was diagnosed clinically (typical forms) and histologically (atypical forms) by a calibrated examiner. A total of 487 adults (20-77 years) attending the same dental clinic were the controls. The two groups were homogeneous in terms of age, gender and occupation. Subjects were tested for anti-HCV antibodies. The odds ratio (OR) for OLP attributable to HCV infection was non-significant [OR 1.2, 95% confidence interval (95CI) 0.3-4.8], suggesting that the association between HCV and OLP was weak in the Iranian context. Meta-analysis of observational studies characteristics of primary studies were that cases were diagnosed clinically (only typical forms) and histologically and exposure was assessed through anti-HCV antibodies. Exposed/unexposed cases/controls were extracted and zero values were appropriately transformed. As much as 44 studies, including the present, were located. Publication bias could not be totally excluded. The pooled OR, estimated using the random-effect model, was 2.8 (95CI 2.4-3.2). Sensitivity analysis confirmed the robustness of results. Subgroup analysis showed non-significant differences between American/European and Asian/African studies. The fraction of global OLP cases associated with HCV (population attributable fraction) was 2.1% (95CI 1.9-2.2%). Although HCV and OLP were significantly associated, the majority of OLP patients were not affected by HCV.