Estimating Work-Related Indirect Costs in Allergic Rhinitis and Asthma Using a Daily Combined Symptom-Medication Score: A MASK-air Study in Collaboration With the EAACI Methodology Committee

BACKGROUND: Allergic rhinitis and asthma can impair work productivity. OBJECTIVE: To validate a daily work productivity visual analogue scale (VAS work), comparing it with the Work Productivity and Activity Impairment questionnaire plus Classroom Impairment Questions: Allergy Specific (WPAI+CIQ:AS) and also to quantify how allergy control relates to work impairment and indirect costs. METHODS: We conducted a cross-sectional study using data from the MASK-air app. Patients recorded daily VAS and weekly WPAI+CIQ:AS responses. We calculated correlations between VAS work and WPAI+CIQ:AS outcomes. Mixed-effects regression models assessed associations between disease control, measured by the Combined Symptom-Medication Score (CSMS) and the electronic daily asthma control score (e-DASTHMA), and VAS work. Indirect costs were estimated using the human capital approach, applying VAS-based productivity losses to country-specific wage distributions. RESULTS: VAS work correlated strongly with the WPAI+CIQ:AS, with Spearman coefficients 0.70 or higher for total work impairment and presenteeism. Each 1-point increase in CSMS and e-DASTHMA was associated with mean 0.97- and 0.79-point increases in VAS work, respectively. On poorly controlled days, the estimated daily indirect cost based on CSMS ranged from US $12.50 purchasing power parities (PPP) (P25-P75, 5.60-26.70) in Brazil to US $129.90 PPP (P25-P75, 80.40-199.40) in Iceland. Based on e-DASTHMA, daily estimates ranged from US $9.30 PPP (P25-P75, 3.70-21.50) in Brazil to US $101.90 PPP (P25-P75, 51.20-172.40) in Iceland. CONCLUSIONS: VAS work is a valid simple daily measure of work impairment due to rhinitis and asthma. CSMS and e-DASTHMA can be used to estimate productivity losses attributable to poor disease control.