Assessing productivity loss and activity impairment in severe or difficult-to-treat asthma.
OBJECTIVE
Asthma can be associated with substantial productivity loss and activity impairment, particularly among those with the most severe disease. We sought to assess the performance characteristics of an asthma-specific adaptation of the Work Productivity and Activity Impairment Questionnaire (WPAI:Asthma) in patients with either severe or difficult-to-treat asthma.


METHODS
We analyzed 2529 subjects from The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study. The WPAI:Asthma was administered at baseline and at 12 months. Asthma control and quality-of-life were simultaneously assessed using the Asthma Therapy Assessment Questionnaire and Mini-Asthma Quality-of-Life Questionnaire, respectively.


RESULTS
Severe versus mild-to-moderate asthma was associated with a greater percentage of impairment at work (28% vs. 14%), at school (32% vs. 18%), and in daily activities (41% vs. 21%). At baseline, greater asthma control problems correlated with higher levels of impairment as measured by the WPAI (work: r = 0.54, school: r = 0.37, activity: r = 0.55). Over the 12-month follow-up period, improved quality-of-life correlated with decreased levels of impairment (work: r = -0.42, school: r = -0.36, activity: r = -0.48). In multivariate analyses, greater than 10% overall work impairment at baseline predicted emergency visits (OR 2.6 [1.6, 4.0]) and hospitalization (OR 4.9 [1.8, 13.1]) at 12 months.


CONCLUSIONS
The WPAI:Asthma correlates with other self-reported asthma outcomes in the expected manner and predicts health-care utilization at 12 months when administered to patients with severe or difficult-to-treat asthma.
Chen
Hubert
H
Department of Medicine, University of California, San Francisco, CA, USA, and Genentech Inc., South San Francisco, CA, USA. hubert.chen@ucsf.edu
Blanc
Paul D
PD
Hayden
Mary L
ML
Bleecker
Eugene R
ER
Chawla
Anita
A
Lee
June H
JH
D000041:Absenteeism; D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000191:economics*; D004526:Efficiency; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D018582:Sick Leave / Q000191:economics*; D017211:Treatment Failure
D018927:Anti-Asthmatic Agents