Paul Cullinan Imperial College and Royal Brompton Hospital London p.cullinan@imperial.ac.uk

2. LUNGS AT WORK www.lungsatwork.org.uk At sea with asthma MCA Maritime Health Seminar 2012 Paul Cullinan Imperial College and Royal Brompton Hospital London p.cullinan@imperial.ac.uk 020 7351 8341

3. MCA doctors manual 2010

4. MCA doctors manual 2010

5. MCA doctors manual 2010

6. Asthma The revised medical guidelines, effective from January 2010, were pretty harsh on asthmatics and painted a pessimistic picture for individuals who used any inhaler more than two days a month and limited some candidates to near coastal waters. However, a significant minority of young yachties remain exceptionally well on daily preventer inhalers with a very occasional need for a puff of reliever inhaler and also have not had an asthma emergency for years, if ever. In these circumstances, the MCA subsequently recommended a pragmatic approach until experience clarified the position

7. The ‘PEGASUS’ project: rationale • pre-employment/pre-placement screening for asthma happens: • frequently • uncertainly • inconsistently • for many different reasons • available guidance is: • limited • sometimes of uncertain logic • often ‘dated’ • there have been important changes in: • ‘asthma’ • attitudes to discrimination • relevant legislation

8. ‘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

9. The prognosis of childhood asthma • Around two-thirds of children with asthma in childhood will be free of wheeze by early adulthood • Remission is more common in males, in those whose asthma started after the age of 5, in those without accompanying rhinitis or eczema and in those with no family history of asthma. • One third of those with asthma in remission at age 18 have a relapse of their disease by the age of 26. • A positive response to a metacholine challenge test at age 15 was associated with a 50% likelihood of subsequent relapse (i.e. a positive predictive value of 50%). A negative test result at that age had a (negative) predictive value of 67%. • Importantly, asthma that represents a relapse of remitted childhood disease appears, in general, to have a mild course:

10. evidence review: what is the prognostic value of provocation testing? I had asthma my asthma went away 30% my asthma has come back 30% 3 12 21 26

11. evidence review: what is the prognostic value of provocation testing? my asthma will come back 30% - I had asthma my asthma went away 30% histamine test + (10%) my asthma will come back 85% 3 12 21 26 • if it comes back: • it’s usually mild • and easy to manage

12. provocation testing in prospective firefighters: RBH experience (in progress)

13. asthma: severity and performance

14. ‘asthma’ • asthma is variable • people with asthma are not • most asthma is predictable (?) • most asthma is readily treatable • severity ≠ control David Beckham has asthma, agent confirms John has been intubated 13 times for status asthmaticus

15. evidence review • difficult • patchy • sometimes misleading ... • ... and sometimes misguided ... • ... but broadly worthwhile

16. evidence review

17. registration date left practice qualifying date past medical history “future” exacerbations 1.07.1998 1.07.2000 qualification window 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. • aged 16-40 between 1998 and 2000 • ≥1 asthma prescription during the qualification window • 5 years pre and post follow up

18. definition of cohort – why not use asthma diagnosis? 135 codes – including Quality and Outcomes Framework (QOF) codes below • brittle asthma • hyperreactive airways disease • asthma • bronchial asthma • extrinsic (atopic) asthma • allergic asthma • childhood asthma • hayfever with asthma • pollen asthma • extrinsic asthma w/out status asthmaticus • extrinsic asthma w/status asthmaticus • extrinsic asthma w/asthma attack • extrinsic asthma nos • instrinsic asthma • late onset asthma • intrinsic asthma nos • mixed asthma • acute exacerbation of asthma • asthma unspecified • status asthmaticus nos • severe asthma attack • asthma attack • asthma attack nos • late-onset asthma • asthma nos • exercise induced asthma • allergic asthma nec • allergic bronchitis nec • intrinsic asthma w/status asthmaticus • intrinsic asthma w/out status asthmaticus • intrinsic asthma w/asthma attack

19. 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)

20. trajectories: findings 1

21. trajectories: findings 1

22. trajectories: findings 1

23. trajectories: findings 2

24. trajectories: findings 2

25. trajectories: findings 2

26. trajectories: findings 2

27. trajectories: findings 3

28. Years 1-5: 13.6% Qualification Year 1: 8.4% Year 2: 5.6% Year 3: 5.5% Year 4: 6.0% Year 5: 6.2% Patients who had at least one exacerbation in each period Patients who had at least one exacerbation in a given period without having exacerbations in previous periods

29. findings: 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