The disease burden of infectious diseases in Belgium · The disease burden of infectious diseases in Belgium. ... YLL = Years of Life Lost = M×RLE The disease burden of infectious

Rue Juliette Wytsmanstraat 14 | 1050 Brussels | BelgiumT +32 2 642 5035 | [email protected] | http://www.wiv-isp.be

The disease burden of infectious diseases in Belgium

Brecht Devleesschauwer18/05/2017



Burden of disease

• How to define disease “impact” or “importance”?

• Disease have an impact on multiple aspects

Burden of disease = quantification of any of these aspects

This requires specific metrics


Burden of disease

• Which disease is most important?

Number of cases, number of deaths Severity of case: duration, reduction quality of life Severity of death: residual life expectancy

Summary Measures of Population Health


Disability-Adjusted Life Years

• 1 DALY = 1 healthy life year lost• Summary measure of population health Morbidity + mortality Disease occurrence + disease severity

• DALY = YLD + YLL YLD = Years Lived with Disability

= Number of incident cases×Duration×Disability Weight YLL = Standard Expected Years of Life Lost

= Number of deaths×Residual Life Expectancy


Disability-Adjusted Life Years

DALY = YLD + YLL YLD = Years Lived with Disability = N×D×DW YLL = Years of Life Lost = M×RLE


20 60Age

DW

01

0

90

40 × 0.25= 10 YLDs

30 × 1= 30 YLLs

0.25

10 + 30 = 40 DALYs

Disability Weights

• Relative severity of symptom/health state 0 = 0% = perfect health

1 = 100% = worst possible health state, death


0 10.005: hearing loss, minor 0.433: migraine

0.494: amputation of both legs, without treatment

0.756: schizophrenia, acute stage

0.072: controlled epilepsy

Disease models

Disease model, outcome tree• Schematic representation of “health states” acute, chronic stages complications (sequelae, long-term health outcomes) death + multiple severity levels


Disease models


Campylobacter spp.

DALY calculation in practice


Study population definition

Disease model definition

Data collection Data adjustment

DALY calculation

Surveillance pyramid

• Tip of the ice berg• .. through the eyes of a

drunken sailor


Underestimation

MultiplicationFactors

Data adjustments


Apparent incidence

True incidence

DALYsMultiplication

factors

Disease model

Burden of Infectious Diseases

• ECDC: Burden of CommunicableDiseases in Europe (BCoDE) 32 communicable diseases 6 healthcare associated infections Burden of disease “toolkit”

• WHO: Foodborne Disease BurdenEpidemiology Reference Group (FERG) 31 foodborne microbiological and

chemical hazards http://collections.plos.org/ferg2015







WIV-ISP National Burden of Disease Study• Burden of community-acquired infectious diseases surveillance data + correction factors BCoDE & FERG disease models

• Burden of healthcare-associated infectious diseases point prevalence survey (2011, 2017) BCoDE disease models

• Results expected end 2017



PhD research• Burden of congenital toxoplasmosis and

cytomegalovirus infection Suzanne Smit, UGent/UCL

• Burden of bacterial foodborne diseases Charline Maertens de Noordhout, UCL

• Burden of Lyme disease Laurence Geebelen, WIV-ISP/UCL



Burden of congenital toxoplasmosis and CMV• Public health impact of congenital toxoplasmosis and

cytomegalovirus infection in Belgium, 2013: a systematic review and data synthesis (Clinical Infectious Diseases, in press)


Disease Incidence DALYs DALYs per case

Congenitaltoxoplasmosis

69(18–131)

188(43–419)

2.7(1.2–5.0)

CongenitalCMV infection

651(516–802)

1976(757–4067)

3.0(1.8–5.2)

Discussion

Acknowledge limitations

• Measures problems, not solutions potential for health gain, unmet needs does not replace cost-effectiveness studies

• Health impact is just one of many aspects


• economic impact• rare, but severe• stakeholder interests• general awareness• …

Discussion

Relevance of burden of infectious diseases estimates?• Public health policy monitor trends, evaluate past actions, inform new

prevention/control

• Research identify “unmet medical needs”

• Clinical laboratories information on underreporting

• General practitioners contribute to differential diagnosis, patient awareness


Rue Juliette Wytsmanstraat 14 | 1050 Brussels | BelgiumT +32 2 642 5035 | [email protected] | http://www.wiv-isp.be

Thank you


Burden of bacterial foodborne diseases• Burden of salmonellosis, campylobacteriosis and

listeriosis in Belgium from 2012 to 2020: a time series analysis (Eurosurveillance, in press)


SalmonellosisCampylobacteriosisListeriosis

Documents

The disease burden of infectious diseases in Belgium · The disease burden of infectious diseases in Belgium. ... YLL = Years of Life Lost = M×RLE The disease burden of infectious