The incidence-based and pathogen-based disability-adjusted life-years approach for measuring infectious disease burden in Europe: the Burden of Communicable Diseases in Europe (BCoDE) project

Abstract

BackgroundMost estimates of disease burden due to infectious diseases focus on the impact of acute infections and do not fully capture the effects of (long-term) sequelae. To provide evidence-based and comparable estimates, the European Centre for Disease Prevention and Control (ECDC) initiated the Burden of Communicable Diseases in Europe (BCoDE) project. MethodsDisability-adjusted life-years (DALYs) were used in an incidence-based and pathogen-based approach to accommodate infectious disease characteristics. This approach involves outcome trees representing the natural history of diseases and links future sequelae to the initial infection by conditional probabilities. For calculating years of life lost (YLLs), life expectancy at birth for males and females was set to 79·9 and 82·5 years, respectively (Global Burden of Disease [GBD] 2004 study standards). For YLLs due to disability, disability weights were taken from the 2004 GBD study and from additional sets or proxies. Multiplication factors (MFs) were used to adjust for underestimation of country-specific incidences (average reported cases 2005–2007). Disease models for 32 pathogens were built in Excel, where @Risk was used to model uncertainty. No time discounting or age weighting was applied. FindingsTaking the example of hepatitis B in Germany, a loss of 7745 DALYs per year (95% CI 5527–10 256) was estimated, resulting in 9·4 DALYs per 100 000 (95% CI 6·7–12·4). 2·2% (170·4) of DALYs were due to acute infections. Chronic infections resulted in a loss of 2852 DALYs per year (95% CI 2455–3275). The disease burdens due to compensated liver cirrhosis, decompensated liver cirrhosis, and hepatocellular carcinoma were estimated at 637 DALYs per year (95% CI 478–792), 2150 DALYs per year (1294–3049), and 1790 DALYs per year (464–3376), respectively, together accounting for 59% (4577) of the overall DALYs. InterpretationThe BCoDE methodology quantifies the burden of short-term and long-term sequelae due to present infection. Quality of notification data and choice of appropriate MFs are crucial as these are the most sensitive inputs. FundingThe BCoDE consortium has been funded by the European Centre for Disease Prevention and Control (Specific agreement No. 1 to Framework Partnership Agreement GRANT/2008/003) for the conduct of burden of infectious disease studies in Europe. The funding source had no influence on writing the manuscript or on the decision to submit the abstract for publication. The corresponding author did not get any payment for writing the abstract from a pharmaceutical industry or other agency. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.