The Pathogen- and Incidence-Based DALY Approach: An Appropriated Methodology for Estimating the Burden of Infectious Diseases

Marie-Josée J Mangen,On Behalf Of The Bcode Consortium ,Dietrich Plass,Nikolai Mühlberger,Taavi Lai,Cheryl L Gibbons,Mirjam E E Kretzschmar,Arie H Havelaar,Alessandro Cassini,Alies Van Lier,Juanita A Haagsma,Piotr Kramarz,Chiara De Waure,R John Brooke

doi:10.1371/journal.pone.0079740

Abstract

In 2009, the European Centre for Disease Prevention and Control initiated the ‘Burden of Communicable Diseases in Europe (BCoDE)’ project to generate evidence-based and comparable burden-of-disease estimates of infectious diseases in Europe. The burden-of-disease metric used was the Disability-Adjusted Life Year (DALY), composed of years of life lost due to premature death (YLL) and due to disability (YLD). To better represent infectious diseases, a pathogen-based approach was used linking incident cases to sequelae through outcome trees. Health outcomes were included if an evidence-based causal relationship between infection and outcome was established. Life expectancy and disability weights were taken from the Global Burden of Disease Study and alternative studies. Disease progression parameters were based on literature. Country-specific incidence was based on surveillance data corrected for underestimation. Non-typhoidal Salmonella spp. and Campylobacter spp. were used for illustration. Using the incidence- and pathogen-based DALY approach the total burden for Salmonella spp. and Campylobacter spp. was estimated at 730 DALYs and at 1,780 DALYs per year in the Netherlands (average of 2005–2007). Sequelae accounted for 56% and 82% of the total burden of Salmonella spp. and Campylobacter spp., respectively. The incidence- and pathogen-based DALY methodology allows in the case of infectious diseases a more comprehensive calculation of the disease burden as subsequent sequelae are fully taken into account. Not considering subsequent sequelae would strongly underestimate the burden of infectious diseases. Estimates can be used to support prioritisation and comparison of infectious diseases and other health conditions, both within a country and between countries.

Highlights

The disability-adjusted life year (DALY), a metric quantifying and combining the impact of premature death and non-fatal health outcomes resulting from disease, was jointly developed by the World Bank, Harvard School of Public Health and the World Health Organization for the Global Burden of Disease and injury (GBD) study [1,2,3,4]
Sequelae-associated burden of disease accounted for 82% and 56% of the total disease burden for Campylobacter spp. and non-typhoidal Salmonella spp. (Figure 3)
If we assume that all GE cases rather than only severe GE cases are at risk to develop Reactive arthritis (ReA) the disease burden increases by 114% for Campylobacter spp. and by 113% for non-typhoidal Salmonella spp., respectively (Figure 4)

Summary

Introduction

The disability-adjusted life year (DALY), a metric quantifying and combining the impact of premature death and non-fatal health outcomes resulting from disease, was jointly developed by the World Bank, Harvard School of Public Health and the World Health Organization for the Global Burden of Disease and injury (GBD) study [1,2,3,4]. DALYs were developed with the aim of supporting priority setting for healthcare and health research, to identify disadvantaged groups for targeted healthcare interventions, and to provide a comparable output measure for interventions, evaluations and planning [4]. Since their development and introduction in the World Development Report [5] DALYs have been widely used in both national and global disease burden estimations To get a better insight into the true disease burden in Europe [13,14,15], the European Centre for Disease Prevention and Control (ECDC) launched the Burden of Communicable Diseases in the European Union, EEA and EFTA countries (BCoDE) project in

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