Paul CullinanImperial College and Royal Brompton HospitalLondonp.cullinan@imperial.ac.uk020 7351 8341

LUNGS AT WORK www.lungsatwork.org.uk

Asthma and employment

Trent OHOctober 2010

PEGASUS: rationale

• pre-employment/pre-placement screening for asthma happens:• frequently• uncertainly• inconsistently• for many different reasons

• available guidance is:• limited• often of uncertain logic• often ‘dated’

• there have been important changes in:• ‘asthma’• attitudes to discrimination• relevant legislation

‘asthma’

• I have asthma• my doctor thinks I have asthma• I had asthma• I sometimes have asthma• I take treatment that is (used) for asthma

‘asthma’

• asthma is variable• people with asthma are not

• most asthma is readily treatable

SOM/SOHN/AOHNPn=664 (30%)

survey: summary

concerns were:• variable• specific• largely predictable• alleviated by experience

logistics re. employing persons with asthma

• OH: screening; monitoring; risk assessment

• employer: fitness; cost

risk of OA exacerbate asthma

sudden attack

risk to others

sickness absence

early retirement

litigation

firefighter 1 3 3 5 2 1 2

police 1 2 4 5 2 2 1

MVRI 3 4 2 2 2 1 3

animal work 3 4 2 1 1–2 2 2

welder or solderer

4 3 2 2 1–3 2 3

diisocyanate work

4 4 4 2 2 2 3

animal work 3–4 4 2 2 2 1–2 3

work with flour 3 4 3 1 3 3 3

any respiratory sensitizer

5 4 2 1 2 1 2

dust, fumes or vapours

2 4 2 1 2 1 2–3

1 none2 mild3 moderate4 very5 extremely

survey: median ‘concern’ scores

evidence review

• does asthma increase the risk of hypersensitive OA?

• how common are workplace irritant responses in asthma?

• do persons with asthma have an increased rate of sickness absence?

• (in current asthma, what is the risk of a future serious event?)

• (in current asthma what is the risk of an unanticipated attack?)

• do people with asthma retire early because of asthma?

• do persons with asthma cost an employer more?

• what are the diagnostic & prognostic values of provocation testing?

• do people with asthma have difficulties wearing breathing apparatus?

evidence review: does asthma increase the risk of hypersensitive OA?

• we don’t know

• atopy does• most people with asthma are atopic• (so are lots of people without asthma)

• studies of asthma do not adjust for atopy

• Canadian animal work apprentices: BHR

evidence review: how common are workplace irritant responses in asthma?

reference setting n prevalent asthma

response rate

workplace aggravation

Saarinen 2003 general population of working persons (Fin)

939 79% 39%

Henneberger 2003

general population of working persons (USA)

64 NA 25%

Henneberger 2006

members of medical insurance plan (USA)

598 61% 41%

Caldeira 2006 birth cohort (Brazil) 227 93% 13%

Axon 1995 adult hospital clinic (UK)

30 97% 31%(≈ OA clinic)

Tarlo 2000 adult hospital clinic (C) 682 NA 7%

Palmer 1997 employees of 4 electronics firms (UK)

21 97% 29%

• common (30%-40%)• real in half• mostly mild (10% more Rx)

• little sector-specific information• related to likely exposure(s)

• no reference• beware ‘aggravation’

reference setting n asthma

response rate

average days sickness in past year

Horn 1989 general practice (UK) 312 58% 8

Jolicoeur 1994

students (US) 51 28% 1.8*

Sørensen 1997

pharmacy customers (DK)

115 NA ~1.5 (estimate)

Ungar 2000 pharmacy customers (C)

386 NA median 0mean 4.4

Sauni 2001 construction workers (Fin)

76 71% 6 (=non-asthma)

Godard 2002 hospital clinic (F) 234 NA 0.03 (mild intermittent)0.58 (mild)5.38 (moderate)8.59 (severe)

Taylor 2005 birth cohort (NZ) 176 NA 3.83

Accordini 2006

general population (I) 527 4.1

Lamb 2006 employees of 27 businesses (USA)

797 NA ~1 (estimate)(3.7 all respondents)

Jansson 2007 general population (S) 115 NA 1.70 (mild intermittent)3.66 (persistent)

evidence review: do persons with asthma have an increased rate of sickness absence?

• essentially, No

• few referenced• skewed

(‘productivity’ data similar)

evidence review: do people with asthma retire early because of asthma?

reference setting n prevalent asthma

response rate

findings

Siebert 2001 Construction workers (D) 757 at baseline

NA No increase in risk vs those without asthma(RR=0.93)

• very little evidence• available, No

• ‘grey’ literature

evidence review: do persons with asthma cost an employer more?

• very little evidence• US• incomplete costings

• Yes, but not for asthma

asthma group non-asthma group

reference asthma other respiratory

other other respiratory

other

Birnbaum 2002 $51 $93 $272 $18 $182

evidence review: what is the value of provocation testing?

‘non-specific’ (histamine/metacholine/mannitol)

• broadly distinguishes current asthma from non-asthma• broadly distinguishes ‘severe’ asthma from ‘not severe’ asthma

• unclear whether it correlates with responses to ‘dust and fumes’

‘more-specific’ (exercise/cold air)

• more difficult to standardise (especially outside hospital)• physical capacity vs asthma

evidence review: what is the value of provocation testing?

I had asthma my asthma went away30%

my asthma will come back30%

3 12 21

26

my asthma will come back85%

histamine test

+ (10%)

-

if it comes back:• it’s usually mild• and easy to manage

in current asthma, what is the risk of future serious events?can they be predicted?

THIN database: 5.5 million patients from 350 participating GP practices in the UK.

past medical history

registration date

1.07.1998 1.07.2000

left practice

“future” exacerbations

qualification window

qualifying date

• aged 16-40 between 1998 and 2000• ≥1 asthma prescription during the qualification window• 5 years pre and post follow up

definitions of exacerbations

‘hospital’ exacerbations• asthma events resulting in attendance at A&E or admission

GP exacerbations• asthma events during out-of-hours consultation or • asthma events suggestive of an emergency exacerbation

‘prednisolone ‘exacerbations• acute prednisolone prescription for asthma • (reliever prescribed within 30 days)

trajectories: findings 1

cumulative risk (%)

years to come: 1st 2nd 3rd 4th 5th

hospital/A&E 0.3 0.6 0.8 1.0 1.2

out-of-hours GP 2.4 3.8 5.1 6.5 8.1

prednisolone 8.3 11.8 14.7 17.3 19.9

trajectories: findings 2

sex age ics

in next 12m: m f 16-24 25-34 35-40 no yes

hospital/A&E 0.2 0.4 0.4 0.3 0.3 0.3 0.5

out-of-hours GP 2.1 2.6 2.4 2.5 2.1 1.7 3.9

prednisolone 7.1 9.2 6.8 8.6 9.9 5.8 14.3

trajectories: findings 2

# ics in past year # events past 5 years years since last exacerbation

in next 12m: 0 1 2 3+ 0 1 2 3+ <1 1-2 2-3 3+

hospital/A&E 0.2 0.3 0.5 1.0 0.3 3.3 17.5 18.8 11.8 8.8 6.5 1.9

out-of-hours GP 1.6 3.9 2.6 5.2 1.7 9.0 12.5 30.8 20.5 11.0 9.2 5.8

prednisolone 6.5 8.2 9.6 15.9 5.9 15.3 24.8 49.5 39.5 22.3 16.2 13.6

trajectories: findings 3

trajectories: findings 4

hospital

year 1

exacerbations (%)

year 2

year 3

year 4

year 5

0.33%

0.27%

0.23%

0.29%

0.25%

represents 0.01%

Results: Exacerbations in the first year post-qualification – summary

• the overall incidence of exacerbations is low

• the (relative) future risk can be related to past experience ...

• those with more asthma prescriptions in the last year

• those with previous exacerbations ...

• ... and those with recent exacerbations

• (women)

• ... but in absolute terms most exacerbations are not predictable