Introduction Tuberculosis (TB) is prevalent in over a third of the world's population, with Asia (31%) and Africa (55%) accounting for most cases. The rising UK incidence of TB is partly due to increasing immigration from these regions. The UK prevalence of Hepatitis B virus (HBV) is estimated at 0.1% and the prevalence of Hepatitis C Virus (HCV) at 0.4%. HBV & HCV are treatable, but are largely asymptomatic until advanced liver disease has occurred. Therefore, HBV and HCV screening are recommended in high risk groups. Patients with TB do not currently undergo routine screening for these viruses, but are offered screening for HIV. HBV & HCV share similar epidemiological hotspots with TB and studies from Asia suggest HBV/HCV are significantly associated with TB infection and Drug-Induced Liver Injury (DILI) from anti-TB therapy. Currently, no studies have investigated the prevalence of viral hepatitis in TB patients in Western Europe, and the risk this poses to DILI.

Aim To assess (1) the prevalence of viral hepatitis in patients undergoing anti-TB therapy in West London; (2) if patients with serological evidence of viral hepatitis are at increased risk of DILI.

Method This was a prospective study of 245 newly diagnosed active (n=167) and latent (n=78) TB patients embarking on anti-TB therapy. Liver Function Tests (LFTs) were performed prior to & 2 weeks after initiation of anti-TB therapy. Patients were offered both HIV and viral hepatitis screening. All patients were tested for viral markers, including HBsAg, HBeAg, HBcAg, anti-HBc, seropositivity to HCV, and to HIV. DILI was defined as ALT elevated twice above the upper limit of normal (2x >ULN (40 IU/L)) any time following normal pre-treatment LFTs.

Results 149 (61%) TB patients were from the Asian Subcontinent and Sub-Saharan Africa, while only 15 (6%) were from the UK, mimicking global TB prevalence. 49 (20%) patients had serological markers for HBV or HCV, of whom 7 (3%) were HBsAg positive (one patient was Asian, two South East Asian and four Sub-Saharan African). 37 patients (15%) had isolated antibody to HBcAg. Five (2.0%) patients were HCV positive (one Asian, two Sub-Saharan African and two UK Caucasian). 17% of those with viral markers had raised pre-treatment ALT. 2.6% of patients tested for HIV were positive for viral hepatitis. 18% of active TB patients and 23% of latent TB patients had markers for viral hepatitis. Ten (5.4%) patients were diagnosed with DILI, of whom only 1 (0.5%) had markers for viral hepatitis. Four (2.2%) patients required treatment interruption due to elevated LFTs, none of whom had serological markers of viral hepatitis.

Conclusion In our West London cohort, TB patients are a high risk group for HBV and HCV carriage. We found no increased risk of DILI in patients with markers of viral hepatitis undergoing anti-TB therapy. Screening for viral hepatitis in high risk groups is advocated by several international associations. However, testing for HBV and HCV in TB patients is not routine practice in the UK. Larger studies are required to identify the highest risk groups within TB populations. Until then, we recommend that screening for viral hepatitis is considered in all patients with TB.