Environmental Valuation & Cost-Benefit News

Abstract:
Objectives: 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.

by Hubert Chen 1, Paul D. Blanc 2, Mary L. Hayden 3, Eugene R. Bleecker 4, Anita Chawla 5 and June H. Lee 6, TENOR Study Group
1. MD, MPH, Department of Medicine, University of California, San Francisco, CA, USA and Genentech, Inc., South San Francisco, CA, USA; E-mail: hubert.chen@ucsf.edu
2. MD, MSPH, Department of Medicine, University of California, San Francisco, CA, USA;
3. FNP, AE-C, School of Nursing, University of Virginia, Charlottesville, VA, USA;
4. MD, Wake Forest University, Winston-Salem, NC, USA
5. PhD, Genentech, Inc., South San Francisco, CA, USA;
6. MD, Genentech, Inc., South San Francisco, CA, USA

Value in Health via Blackwell Publishing www.Blackwell-Synergy.com
Online early article
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1524-4733.2007.00229.x
doi:10.1111/j.1524-4733.2007.00229.x