QueenslandCentre for MentalHealthResearch

The global burden of ADHD &

a meta-analysis of long-term outcomes

Dr Holly ErskineThe University of Queensland Centre for Clinical Research;School of Public Health, The University of Queensland;Queensland Centre for Mental Health Research;Institute for Health Metrics and Evaluation, University of Washington

Introduction

Disclosures: Dr Erskine has previously received an honorarium from Shire

The Global Burden of Disease Study (GBD)

The Global Burden of Disease Study (GBD) quantifies health loss from hundreds of diseases, injuries, and risk factors, so that health systems

can be improved and disparities can be eliminated.

History of measuring burden of disease

• A common unit of measurement is required

for comparison of disease burden between

diseases, countries, age groups, sex, years, etc.

• Historically, the most common unit of

measurement for burden was mortality.

• However, it is important to consider both

mortality and morbidity when measuring

burden.

Measuring burden of disease

Years of life lost due to premature mortality (YLLs)YLLs = number of deaths x life expectancy at age of death

Years lived with disability (YLDs)YLDs = prevalent cases x disability weight

YLLs + YLDs =Disability-adjusted life years (DALYs)

History of GBD• GBD 1990 (Murray & Lopez, 1996)

– 107 diseases and injuries, 8 regions, 5 age groups, 1 time point

• GBD 2000-2004 (WHO collaboration)– 136 diseases and injuries, 14 regions, 4 time points

• GBD 2010 (led by IHME)– 296 diseases and injuries, 187 countries, (21 regions and 7 super-regions), 20

age groups, 5 time points

• GBD 2013 (led by IHME)– 306 diseases and injuries, 188 countries + subnational estimates for 3 countries

(21 regions and 7 super-regions), 20 age groups, 6 time points

• GBD 2015 (led by IHME)– 315 diseases and injuries, 195 countries + subnational estimates for 11 countries

(21 regions and 7 super-regions), 20 age groups, 6 time points

• GBD 2016 (led by IHME)– 333 diseases and injuries, 195 countries + subnational estimates for 12 countries

(21 regions and 7 super-regions), 20 age groups, every year from 1990 onwards

ADHD in GBD

• Not included until GBD 2010

• Estimate burden across the lifespan

• Only non-clinical epidemiological data

is accepted

• Data scarcity in older ages, for LMICs,

and for non-prevalence parameters

• No YLLs, only YLDs

Prevalence of ADHD in ages 5-14 years, 2016

Prevalence of ADHD in Australia by age, 2016

Prevalence in Australia, 5-14 years, 1990-2016

DALYs in Australia, ages 5-14 years, 2016

Rate of DALYs over time, 5-14 years

DALY rankings, 5-14 years, 2016

Implications of GBD

• Recognition of ADHD in the

global health/mental health fields

• Vital information for countries

with young populations

• Potential support ratio –

importance of healthy young

people

Limitations of GBD

• Data scarcity

• Low disability weight for ADHD

• No YLLs – does not mean no increased

risk of mortality

• Disability only considered in terms of

‘current within-the-skin health loss’

– No future burden

– No impact on other areas e.g.

academics, employment

– No burden on families, carers, schools,

etc

5.5%

Potential adverse outcomes of ADHD

Findings

• 101 studies across North America,

Western Europe, and the Asia Pacific

• Sample sizes ranged from 71 to almost

2 million participants

• Years of follow up ranged from 2-40 yrs

• Attrition ranged from 60% to 0%

• Number of outcomes able to be meta-

analysed = 52

• Number of significant odds ratios (ORs)

= 37

Substance use disorders

Long-term outcome Odds ratio 95% CIs No. of data points

Substance use disorder 1.73 1.24-2.41 13

Illicit drug use 2.24 1.43-3.52 8

Illicit drug use disorder 2.57 2.06-3.20 6

Cannabis use 1.67 1.23-2.26 14

Cannabis use disorder 2.51 0.67-9.30 5

Alcohol use 1.00 0.70-1.44 7

Alcohol dependence 1.39 1.06-1.83 8

Regular smoking 2.16 1.77-2.63 13

Tobacco dependence 2.41 1.67-3.48 8

Mental disorders and suicide

Long-term outcome Odds ratio 95% CIs No. of data points

ODD 7.05 2.63-18.85 6

CD 5.40 2.53-11.55 8

ASPD 3.17 1.98-5.08 8

Bipolar disorder 7.09 2.03-24.75 4

Depression 2.31 1.45-3.70 13

Anxiety disorders 1.48 0.89-2.46 9

Panic disorder 2.47 1.10-5.53 4

Suicide attempts 2.48 1.63-3.77 7

Academics and employment

Long-term outcome Odds ratio 95% CIs No. of data points

Failure to complete high school

3.70 1.96-6.99 11

Grade retention 3.64 2.39-5.56 9

Suspension 6.31 2.53-15.73 5

Expulsion 3.19 2.15-4.74 4

No tertiary education 6.47 4.58-9.14 9

Fired 3.92 2.68-5.74 4

Unemployment 1.97 1.01-3.85 4

Criminality

Long-term outcome Odds ratio 95% CIs No. of data points

Criminal acts 1.81 0.94-3.50 7

Arrest 2.43 1.62-3.65 10

Drug-related arrest 1.69 0.75-3.77 4

Violence-related arrest 3.63 2.31-5.70 5

Convictions 2.01 1.25-3.24 6

Incarceration 2.53 1.38-4.63 4

Other outcomes

Long-term outcome Odds ratio 95% CIs No. of data points

Early pregnancy (< 23 years) 2.77 0.67-11.37 5

Vehicular accidents 1.15 0.67-1.99 6

At-fault vehicular accidents 1.98 1.03-3.81 4

Vehicular accidents with injury 2.75 1.47-5.15 4

Driving citations 2.13 1.09-4.19 5

DUI driving citations 1.60 1.00-2.57 5

License revoked/suspended 1.95 1.30-2.92 5

Service use – education 6.37 2.58-15.73 8

Service use – mental health 2.35 1.42-3.89 9

Impact of diagnosis vs symptoms: SUDs

OR1086420

Study

Reef, 2010

Fischer, 2002

Overall

Q=5.13, p=0.16, I2=42%

Fergusson, 2007

Sourander, 2007

OR (95% CI) % Weight

0.70 ( 0.30, 1.30) 25.6

1.04 ( 0.59, 1.84) 33.4

1.23 ( 0.76, 2.00) 100.0

1.84 ( 0.95, 3.55) 28.8

2.40 ( 0.70, 8.30) 12.3

OR1086420

Study

Monuteaux, 2007 Copeland, 2009

Biederman, 2008

Mannuzza, 1993

Overall Q=18.15, p=0.02, I2=56%

DeSanctis, 2014

Mannuzza, 1998

Biederman, 1999

Milberger, 1997b

Gau, 2007

OR (95% CI) % Weight

0.70 ( 0.25, 1.99) 8.4 1.00 ( 0.20, 4.50) 4.8

1.20 ( 0.70, 2.07) 15.0

1.48 ( 0.66, 3.32) 11.0

2.02 ( 1.37, 2.98) 100.0

2.12 ( 1.15, 3.92) 13.8

2.19 ( 0.85, 5.65) 9.3

2.67 ( 1.41, 5.05) 13.4

3.75 ( 1.74, 8.07) 11.6

4.79 ( 2.41, 9.51) 12.7

Symptom scales Diagnostic instruments

1.23 (0.76-2.00) 2.02 (1.37-2.96)

Limitations & Implications

Limitations

• Insufficient data for some outcomes

• Varying quality of the studies

• Control for confounding factors

Implications

• Many health outcomes are serious and persistent

• Not a ‘self-fulfilling prophecy’

• Importance of appropriate treatment at the appropriate time

• Significant potential benefits of prevention

The global burden of ADHD &�a meta-analysis of long-term outcomes�IntroductionThe Global Burden of Disease Study (GBD)History of measuring burden of diseaseMeasuring burden of diseaseHistory of GBDADHD in GBDPrevalence of ADHD in ages 5-14 years, 2016Prevalence of ADHD in Australia by age, 2016Prevalence in Australia, 5-14 years, 1990-2016DALYs in Australia, ages 5-14 years, 2016Rate of DALYs over time, 5-14 yearsDALY rankings, 5-14 years, 2016Implications of GBDLimitations of GBDPotential adverse outcomes of ADHDFindingsSubstance use disordersMental disorders and suicideAcademics and employmentCriminalityOther outcomesImpact of diagnosis vs symptoms: SUDsLimitations & Implications