Disability Adjusted Life Years and acute onset disorders: Improving estimates of the non-fatal burden of injuries and infectious intestinal disease

The population's health faces an array of diseases and injuries. Limited resources compel policy-makers everywhere to focus on threats that are regarded most relevant in terms of public health. The World Health Organization and Worldbank developed an innovative concept which expresses the burden of disease in Disability Adjusted Life Years (DALY). The DALY provides knowledge on the size of health problems and the potential benefit of proposed measures set against similar and comparable data of other problems. However, apart from the obvious advantages, the DALY-concept has been criticized concerning key aspects of the methodology. This thesis addressed four of these controversial aspects: namely (1) deriving disability weights for disorders with complex and heterogeneous recovery patterns, (2) the disregard of comorbid diseases, (3) the arbitrariness of the in- and exclusion of long-term sequelae, and (4) the absence of a criterion to identify cases that are relevant from a public health perspective. These controversial aspects were addressed with regards to two health (care) domains where these aspects are particularly problematic. Both health domains, injuries and infectious intestinal disease, are featured by heterogeneous health outcomes, including the extremes of the severity spectrum and duration, with all types of time-severity relations. This thesis demonstrated satisfactory alternative solutions to these four controversial issues of the DALY concept. As a result, the DALY-concept may be used for burden of disease studies of conditions in which these controversial issues emerge in particular. Application of alternative solutions proposed in this thesis may improve burden of disease estimates considerably

Incidence and mortality from adverse effects of medical treatment in the UK, 1990-2013: levels, trends, patterns and comparisons

Objective: To present an update on incidence and mortality from adverse effects (AEs) of medical treatment in the UK, its four countries and nine English regions between 1990 and 2013. Design: Descriptive epidemiological study on AEs of medical treatment. AEs are shown as a single cause-of-injury category from the Global Burden of Disease (GBD) 2013 study. Data sources: The GBD 2013 interactive data visualisation tools 'Epi Visualisation' and 'GBD Compare'. Outcome measures: The means of incidence and mortality rates with 95% uncertainty intervals (UIs). The estimates are age-standardised. Results: Incidence rate was 175 and 176 cases per 100 000 men, 173 and 174 cases per 100 000 women in 1990 and 2013, in the UK (UI 170-180). The mortality from AEs declined from 1.33 deaths (UI 0.99-1.5) to 0.92 deaths (UI 0.75-1.2) per 100 000 individuals in the UK between 1990 and 2013 (30.8% change). Although mortality trends were descending in every region of the UK, they varied by geography and gender. Mortality rates in Scotland, North East England and West Midlands were highest. Mortality rates in South England and Northern Ireland were lowest. In 2013, agespecific mortality rates were higher in males in all 20 age groups compared with females. Conclusions: Despite gains in reducing mortality from AEs of medical treatment in the UK between 1990 and 2013, the incidence of AEs remained the same. The results of this analysis suggest revising healthcare policies and programmes aimed to reduce incidence of AEs in the UK

Mapping EQ-5D utilities to GBD 2010 and GBD 2013 disability weights : results of two pilot studies in Belgium

Background: Utilities and disability weights (DWs) are metrics used for calculating Quality-Adjusted Life Years and Disability-Adjusted Life Years (DALYs), respectively. Utilities can be obtained with multi-attribute instruments such as the EuroQol 5 dimensions questionnaire (EQ-5D). In 2010 and 2013, Salomon et al. proposed a set of DWs for 220 and 183 health states, respectively. The objective of this study is to develop an approach for mapping EQ-5D utilities to existing GBD 2010 and GBD 2013 DWs, allowing to predict new GBD 2010/2013 DWs based on EQ-5D utilities. Methods: We conducted two pilot studies including respectively four and twenty-seven health states selected from the 220 DWs of the GBD 2010 study. In the first study, each participant evaluated four health conditions using the standard written EQ-5D-5 L questionnaire. In the second study, each participant evaluated four health conditions randomly selected among the twenty-seven health states using a previously developed web-based EQ-5D-5 L questionnaire. The EQ-5D responses were translated into utilities using the model developed by Cleemput et al. A loess regression allowed to map EQ-5D utilities to logit transformed DWs. Results: Overall, 81 and 393 respondents completed the first and the second survey, respectively. In the first study, a monotonic relationship between derived utilities and predicted GBD 2010/2013 DWs was observed, but not in the second study. There were some important differences in ranking of health states based on utilities versus GBD 2010/2013 DWs. The participants of the current study attributed a relatively higher severity level to musculoskeletal disorders such as ‘Amputation of both legs’ and a relatively lower severity level to non-functional disorders such as ‘Headache migraine’ compared to the participants of the GBD 2010/2013 studies. Conclusion: This study suggests the possibility to translate any utility derived from EQ-5D scores into a DW, but also highlights important caveats. We observed a satisfactory result of this methodology when utilities were derived from a population of public health students, a written questionnaire and a small number of health states in the presence of a study leader. However the results were unsatisfactory when utilities were derived from a sample of the general population, using a web-based questionnaire. We recommend to repeat the study in a larger and more diverse sample to obtain a more representative distribution of educational level and age

An analogy between socioeconomic deprivation level and loss of health from adverse effects of medical treatment in England

Background: The purpose of this study was to show whether and how levels, trends and patterns obtained from estimates of premature deaths from adverse effects (AEs) of medical treatment depended on the deprivation level in England over the 24-year period, 1990-2013. We provide a report to inform decision-making strategies to reduce the burden of disease arising from AEs of medical treatment in the most deprived areas of the country. Methods: Comparative analysis was driven by a single cause-of-injury category - AEs of medical treatment - from the Global Burden of Disease 2013 study. We report the mean values with 95% uncertainty intervals (UIs) for five socioeconomic deprivation areas of England. Results: In the most deprived areas of England, the death rate declined from 2.27 (95% UI 1.65 to 2.57) to 1.54 (1.28 to 2.08) deaths (32.16% change). The death rate in the least deprived areas was 1.22 (0.88 to 1.38) in 1990; it was 1.17 (0.97 to 1.59) in 2013 (4.1% change). Regarding disability-adjusted life year (DALY) rates, the same trend is observed. Although the gap between the most deprived and least deprived populations of England narrowed with regards to number of deaths, and rates of deaths and DALYs from AEs of medical treatment, inequalities between marginal levels of deprivation remain. Conclusions: The study suggests that a relationship between deprivation level and health loss from the AEs of medical treatment across England is possible. This could then be used when devising and prioritising health policies and strategies

Mortality burden of cardiovascular disease attributable to ambient PM_2.5 exposure in Portugal, 2011 to 2021

Background: Exposure to high levels of environmental air pollution causes several health outcomes and has been associated with increased mortality, premature mortality, and morbidity. Ambient exposure to PM2.5 is currently considered the leading environmental risk factor globally. A causal relationship between exposure to PM2.5 and the contribution of this exposure to cardiovascular morbidity and mortality was already demonstrated by the American Heart Association. Methods: To estimate the burden of mortality attributable to environmental risk factors, a comparative risk assessment was performed, considering a “top-down” approach. This approach uses an existing estimate of mortality of the disease endpoint by all causes as a starting point. A population attributable fraction was calculated for the exposure to PM2.5the overall burden of IHD and stroke was multiplied by the PAF to determine the burden attributable to this risk factor. The avoidable burden was calculated using the potential impact fraction (PIF) and considering the WHO-AQG 2021 as an alternative scenario. Results: Between 2011 and 2021, the ambient exposure to PM2.5 resulted in a total of 288,862.7 IHD YLL and a total of 420,432.3 stroke YLL in Portugal. This study found a decreasing trend in the mortality burden attributable to PM2.5 exposure, for both males and females and different age-groups. For different regions of Portugal, the same trend was observed in the last years. The mortality burden attributable to long-term exposure to PM2.5 was mainly concentrated in Lisbon Metropolitan Area, North and Centre. Changes in the exposure limits to the WHO recommended value of exposure (WHO-AQG 2021) have a reduction in the mortality burden due to IHD and stroke attributable to PM2.5 exposure, in Portugal. Conclusion: Between 2011 and 2021, approximately 22% and 23% of IHD and stroke deaths were attributable to PM2.5 exposure. Nevertheless, the mortality burden attributable to cardiovascular diseases has been decreasing in last years in Portugal. Our findings provide evidence of the impact of air pollution on human health, which are crucial for decision-making, at the national and regional level.</p

Disability Adjusted Life Years and minimal disease: application of a preference-based relevance criterion to rank enteric pathogens

Background: Burden of disease estimates, which combine mortality and morbidity into a single measure, are used increasingly for priority setting in disease control, prevention and surveillance. However, because there is no clear exclusion criterion for highly prevalent minimal disease in burden of disease studies its application may be restricted. The aim of this study was to apply a newly developed relevance criterion based on preferences of a population panel, and to compare burden of disease estimates of five foodborne pathogens calculated with and without application of this criterion. Methods: Preferences for twenty health states associated with foodborne disease were obtained from a population panel (n = 107) with the Visual Analogue Scale and the Time Trade-off (TTO) technique. The TTO preferences were used to derive the relevance criterion: if at least 50% of a panel of judges is willing to trade-off time in order to be restored to full health the health state is regarded as relevant, i.e. TTO median is greater than 0. Subsequently, the burden of disease of each of the five foodborne pathogens was calculated both with and without the relevance criterion. Results: The panel ranked the health states consistently. Of the twenty health states, three did not meet the preference-based relevance criterion. Application of the relevance criterion reduced the burden of disease estimate of all five foodborne pathogens. The reduction was especially significant for norovirus and rotavirus, decreasing with 94% and 78% respectively. Conclusion: Individual preferences elicited with the T

Systematic review of foodborne burden of disease studies: Quality assessment of data and methodology

Burden of disease (BoD) studies aim to identify the public health impact of different health problems and risk factors. To assess BoD, detailed knowledge is needed on epidemiology, disability and mortality in the population under study. This is particularly challenging for foodborne disease, because of the multitude of causative agents and their health effects. The purpose of this study is to systematically review the methodology of foodborne BoD studies. Three key questions were addressed: 1) which data sources and approaches were used to assess mortality, morbidity and disability?, 2) which methodological choices were made to calculate Disability Adjusted Life Years (DALY), and 3) were uncertainty analyses performed and if so, how? Studies (1990-June 2012) in international peer-reviewed journals and grey literature were identified with main inclusion criteria being that the study assessed disability adjusted life years related to foodborne disease. Twenty-four studies met our inclusion criteria. To assess incidence or prevalence of foodborne disease in the population, four approaches could be distinguished, each using a different data source as a starting point, namely 1) laboratory-confirmed cases, 2) cohort or cross-sectional data, 3) syndrome surveillance data and 4) exposure data. Considerable variation existed in BoD methodology (e.g. disability weights, discounting, age-weighting). Almost all studies analyzed the effect of uncertainty as a result of possible imprecision in the parameter values. Awareness of epidemiological and methodological rigor between foodborne BoD studies using the DALY approach is a critical priority for advancing burden of disease studies. Harmonization of methodology that is used and of modeling techniques and high quality data can enlarge the detection of real variation in DALY outcomes between pathogens, between populations or over time. This harmonization can be achieved by identifying substantial data gaps and uncertainty and establish which sequelae of foodborne disease agents should be included in BoD calculations