Background
Lung diseases are among the most frequent and most serious ailments in Denmark. Preventive health checks including spirometry can be used to detect lung diseases earlier. Over time the attendance at preventive health checks has decreased and at present the response rate is approximately 50%. Little is known about initiatives that can influence the attendance rate.

Objectives
To examine whether focused information on spirometry in the invitation material will influence the attendance in preventive health checks.

Materiel/Methods
Design: A randomized controlled study on information on spirometry embedded in “Check your health Prevention Program, CHPP” from 2015-16. CHPP is a house-hold cluster randomized controlled trial offering a preventive health check to 30-49 year olds in a Danish municipality during the years 2012 through to 2017 (n= 26,216), carried out in collaboration between Central Denmark Region, general practitioners in Randers and the Department of Public Health, University of Aarhus. The health checks are performed at a local health care center with a subsequent health interview at the participants own general practitioner.
Intervention: During 2015-16, 5,200 citizens aged 30-49 years will be randomized into two groups: The intervention group receives an invitation which highlights the value of spirometry as part of a health check and information about lung diseases. The control group will receive a standard invitation.
Primary outcome measure is effect on attendance. The characteristics of the 2 groups will be described according to sex, age, smoking history, spirometry values and lung symptoms.

Results
This is a presentation of the method, therefore we do not have any results yet.
Conclusion
The results from the present study are expected to contribute with important knowledge about the value of information on spirometry in invitations to health checks measured at different levels of attendance – as described above.

Point of discussion
The study is part of a Ph.D. project evaluating the use of spirometry as an element in preventive health checks. Further studies in the Ph.D. project will evaluate whether early spirometry measurements can be used to predict future lung disease and describe the follow up of patients with abnormal spirometry measurements at the general practitioner.

Disclosure of interest: None to declare.

Key words: early spirometry, preventive health check, attendance.

Correspondence: Lene Maria Ørts, MD. E-mail: lmo@ph.au.dk