Background
Current asthma guidelines, including those of the European Respiratory Society (ERS) and American Thoracic Society (ATS), suboptimally predict asthma remission, disease severity, and health-care utilisation. We aimed to establish a novel approach to assess asthma severity based on asthma health-care burden data.
Methods
We analysed prospectively collected data from the Severe Asthma Research Program III (SARP III; USA) and the European Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED; 11 European countries) to calculate a composite burden score based on asthma exacerbations and health-care utilisation, which was modified to include the use of short-acting beta agonists (SABAs) to reflect asthma symptom burden.
Findings
In SARP III, 528 adult participants with asthma were followed up for a mean of 4·4 (SD 1·6) years, and 312 (59%) had severe asthma according to the ERS-ATS definition. Among the 205 participants with asthma who used rescue SABAs daily, 90 used these two or more times a day. In U-BIOPRED, 509 adult participants with asthma were followed up for 1 year, and 421 (83%) had severe asthma. The burden score was less than 1·29 per patient-year in 106 (34%) of 312 SARP III participants and in 80 (19%) of 421 U-BIOPRED participants with severe asthma. By contrast, the burden score was above the median value in 58 (28%) SARP III and 24 (27%) U-BIOPRED participants with non-severe asthma. In both cohorts, the burden score negatively correlated with lung function, asthma control, and quality of life. A burden score of 0·15 or lower predicted asthma remission with a sensitivity greater than 91% and a specificity of 99%.
Interpretation
Our findings highlight considerable discrepancies between the current definition of asthma severity and our burden score. Although the definition of severe asthma proposed by the ERS-ATS and the and Global Initiative for Asthma (GINA) is based on prescribed asthma medications, our personalised health-care burden score includes patient-centred data that reflect disease severity and accurately predicts asthma remission. Subject to prospective validation, the burden score could help to optimise the management of high-risk individuals with asthma.
Funding
SARP III: US National Heart, Lung, and Blood Institute; AstraZeneca; Boehringer Ingelheim; Genentech; GlaxoSmithKline; Sanofi Genzyme/Regeneron; and Teva Pharmaceuticals. U-BIOPRED: Innovative Medicines Initiative Joint Undertaking (EU's Seventh Framework Programme and European Federation of Pharmaceutical Industries and Associations) and eTRIKS project.