Development of self-assessed work ability among middle-aged asthma patients—a 10 year follow-up study

Abstract

Objective

The prevalence of asthma has been growing among working age people over the last decades. In this study, we examine the development of Work Ability Score (WAS) among middle-aged asthmatics in a longitudinal setting, in order to find risk factors for poor development.

Methods

We followed the development of WAS trends during 10 years in a cohort of 529 middle-aged asthmatics, who were active in working life. Follow-up questionnaires were mailed in years 1, 2, 4, 6, 8, and 10. To study the development of WAS over time, we computed the discrete Frechet distance, which describes the similarity between the shapes of WAS curves.

Results

Sixty-eight percent of the patients’ WAS remained good or excellent throughout the follow-up period, while 24% of the patients WAS trend remained moderate. However, in 8%, the WAS was poor already in baseline and decreased further throughout the study. Using logistic regression, the moderate/poor development was associated significantly with high body mass index (BMI), pack years, adult onset asthma, physically strenuous work, number of co-morbidities, especially in psychiatric conditions, hypertension, and gastroesophageal reflux disease(GERD). When the model was adjusted for age and gender, adulthood onset of asthma and pack years lost their significance. Based on medication (high dose of inhaled corticosteroids (ICS) and second controller in use), 8% of the patients had severe asthma.

Conclusion

In the great majority of middle-aged asthma patients WAS remained stable throughout the follow-up period. However, 8% of the patients, who had more severe asthma and multiple co-morbidities, showed significantly poorer outcomes.

Keywords:

• Asthma
• employment
• work ability
• work ability score
• severe asthma
• co-morbidity
• longitudinal study
• quality of life
• frechet distance

Acknowledgments

The authors would like to thank clinical research nurses Ms Kerstin Ahlskog, Kirsi Lindgren, and Päivi Laakso for their skillful patient recruitment, Ms Tuula Lahtinen for the monitoring of the project, Ms Sari Nummijoki, Tinja Kanerva, and Elli Niemi for transforming the questionnaires into electronic format, Lizzie Ingham for proofreading the article and Tessa Ramsden for proofreading the translation of the questionnaire.

Declaration of interest

The authors report no conflict of interest.

Additional information

Funding

This work was supported by The Research Foundation of the Pulmonary Diseases; Turku University Hospital VTR funding under Grant 13946.