Chest
Volume 141, Issue 1, January 2012, Pages 66-72
Journal home page for Chest

Original Research
Asthma
The Relationship of Asthma Impairment Determined by Psychometric Tools to Future Asthma Exacerbations

https://doi.org/10.1378/chest.11-0574Get rights and content

Background

Impairment and risk are considered separate domains of asthma control, but relationships between them are not completely understood. We compared three validated questionnaires reflecting asthma impairment in their ability to predict future exacerbations.

Methods

Two thousand six hundred eighty patients with persistent asthma completed a survey that included the Asthma Control Test (ACT), mini-Asthma Quality of Life Questionnaire (mAQLQ), and Asthma Impact Survey (AIS-6), as well as a history of exacerbations in the prior 12 months. An exploratory factor analysis was performed using the questions of the three tools, and individual patient factor scores were calculated. Independent relationships between predictors (tools and factors) and exacerbations the following year captured from administrative data were evaluated.

Results

Each tool was significantly related (P < .0001) to future exacerbations above and beyond the risk conferred by prior exacerbations (relative risk [RR] = 1.3). When prior exacerbations were included in the model, the three impairment tools provided similar and overlapping information, such that only the mAQLQ entered the model (RR = 1.3; 95% CI, 1.1-1.5). Factor analysis revealed three factors (symptoms, activity, and bother) that were each significantly associated (P < .0001) with future asthma exacerbations. However, only the activity factor was independently related to future exacerbations.

Conclusions

Asthma impairment is significantly related to the risk of future exacerbations, but the ACT, mAQLQ, and AIS-6 do not provide independent information from each other in this regard. Interference with activities is the primary subjective component of asthma impairment that is related to the risk of future exacerbations.

Section snippets

Materials and Methods

This study was approved by the Kaiser Permanente Southern California Institutional Review Board (Study number 4940). Informed consent was waived by the institutional review board; completion of the survey was taken as consent to participate. The study patients (aged 18-56 years with Healthcare Effectiveness Data and Information Set-defined persistent asthma in 2006) have been previously described in a report focusing on persistent asthma.15

Patients

The baseline (November 2007) survey was returned by 2,751 patients (20.1%), of whom 2,680 (97.4%) had complete results for all three tools and make up the study cohort for this report. The 2,680 current study patients were primarily female, well-educated nonsmokers on regular asthma controller therapy, and a majority were white (Table 1). More than one-third of the patients reported unscheduled asthma visits in the prior 12 months, and nearly 40% required oral corticosteroids for asthma

Discussion

Asthma impairment (including asthma control and asthma-specific quality of life) and risk of asthma exacerbations are considered two separate domains, but the current study confirms that these two domains are related to each other. Patients who suffered asthma exacerbations during 12 months of follow-up had significantly greater baseline asthma impairment (as assessed by each of the three tested tools: ACT, mAQLQ, and AIS-6) compared with patients who did not experience exacerbations during the

Acknowledgments

Author contributions: Dr Schatz: contributed to study design, data analysis, data interpretation, and manuscript preparation, and is the guarantor of the manuscript.

Dr Zeiger: contributed to study design, data interpretation, and manuscript preparation.

Dr Yang: contributed to data acquisition, data analysis, and manuscript review.

Ms Chen: contributed to study design, data acquisition, data interpretation, and manuscript review.

Dr Crawford: contributed to study design, data interpretation, and

References (26)

Cited by (0)

Funding/Support: This study was funded by a research grant from Merck & Co, Inc.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (http://www.chestpubs.org/site/misc/reprints.xhtml).

View full text