The burden of hepatitis C in England M. J. Sweeting, 1 D. De Angelis, 1,2 L. J. Brant, 2 H. E. Harris, 2 A. G. Mann 2 and M. E. Ramsay 2 1 MRC Biostatistics Unit, Institute of Public Health, Robinson Way, Cambridge, UK; and 2 Health Protection Agency, London, UK Received June 2006; accepted for publication December 2006 SUMMARY. In England, a large number of individuals are infected with the hepatitis C virus (HCV) and may develop future liver complications, such as decompensated cirrhosis and hepatocellular carcinoma (HCC). Estimates of the mag- nitude of this future burden are required to plan healthcare resources. We have estimated past incidence of HCV infec- tion in England and predict future burden of end-stage liver disease in the HCV-infected population. A model of the natural history of HCV as a series of disease stages was constructed. A back-calculation approach was performed, using the natural history model and data on annual HCC deaths in England from 1996 to 2004 with mention of HCV and hospital episode statistics for end-stage liver disease with HCV. The number of HCV-infected people living with com- pensated cirrhosis is predicted to rise from 3705 [95% credible interval (CrI): 2820–4975] in 2005 to 7550 (95% CrI: 5120–11 640) in 2015. The number of decompensated cirrhosis and/or HCC cases is also predicted to rise, to 2540 (95% CrI: 2035–3310) by 2015. HCV incidence increased during the 1980s, with an annual incidence of 12 650 (95% CrI: 6150–26 450) by 1989. HCV-related cirrhosis and deaths from HCC in England are likely to increase dramat- ically within the next decade. If patients are left undiagnosed and untreated, the future burden of the disease on health- care resources will be substantial. Keywords: back-calculation, disease burden, epidemiology, modelling, natural history. INTRODUCTION Hepatitis C is a blood-borne virus that can lead to cirrhosis and hepatocellular carcinoma (HCC) [1]. Risk factors for infection include injecting drug use (IDU), transfusion of infected blood or blood products, haemodialysis, needle stick injuries and tattoos. Since the introduction of donor screening in the UK in 1991, the majority of reported infections (80%) are in people who have injected drugs [2]. There is much uncertainty around the current burden of hepatitis C virus (HCV) disease in the UK. In England, an estimate based on testing of residual sera in 1996 suggests that around 200 000 people are chronically infected with HCV [3]. However, no information is available on the dis- tribution of infections by disease stage, nor is there any indication on how this might evolve in the near future. Such knowledge is essential to plan an appropriate response to the HCV epidemic, both in terms of prevention and treatment. To fill this knowledge gap, we used a back-calculation approach that employs data on deaths from HCC with mention of HCV (HCC–HCV) and information on HCV dis- ease progression to estimate incidence of HCV over time and predict the consequent incidence of end-stage liver disease. We modelled the natural history of HCV as a series of disease stages with HCC mortality and other liver and non- liver-related mortality as the final end-points. The aim was to estimate the number of individuals occupying each dis- ease stage over time. We used data on trends in HCC deaths, included information from hospital episodes of end-stage liver disease, and explored the effect of incorporating current knowledge on the prevalence of HCV. METHODS Data sources Deaths from hepatocellular carcinoma Disaggregate data from the death entries for all causes of liver cancer [International Classification of Diseases (ICD) 9th edition, code 155 or ICD 10th edition, code C22] were obtained from the Office of National Statistics for the period 1996–2004. These data were provided on request to the Health Protection Agency for use as part of national sur- veillance. By studying the content of 15 diagnosis codes and seven text fields on the death certificates, we identified Abbreviations: HCC, hepatocellular carcinoma; HCV, hepatitis C virus; HES, hospital episode statistic.; HIV, human immuno- deficiency virus; ICD, international classification of diseases; IDU, intravenous drug use. Correspondence: Michael Sweeting, MRC Biostatistics Unit, Institute of Public Health, University Forvie Site, Robinson Way, Cambridge CB2 0SR, UK. E-mail: michael.sweeting@mrc-bsu.cam.ac.uk Journal of Viral Hepatitis, 2007, 14, 570–576 doi:10.1111/j.1365-2893.2007.00851.x Ó 2007 Medical Research Council Journal compilation Ó 2007 Blackwell Publishing Ltd