A structured review evaluating content validity of the Asthma Control Test, and its consistency with U.S. guidelines and patient expectations for asthma control

Abstract

Objective

To assess whether the content of the Asthma Control Test (ACT) served as a valid measure of asthma control (i.e., content validity) by mapping ACT items to the National Heart, Lung and Blood Institute (NHLBI) guideline asthma control definitions, and to language used by patients to describe their asthma.

Data sources

PubMed and EMBASE databases were used for a structured literature analysis.

Study selections

Full-text, English-language articles that reported findings from qualitative studies conducted in adults, focusing on patient descriptors of asthma symptoms, impacts, or severity, were included. Pediatric studies, studies conducted in patients without asthma, and studies that did not contain qualitative data were excluded.

Results

ACT items reflected all domains of asthma impairment described in the NHLBI guidelines, except pulmonary function. Following the literature review, 28 full-text publications were identified that included patient descriptors that could be mapped to ACT items. For example, per ACT Item 1, patients described having trouble at work, school, and completing household chores; and, per ACT Item 2, patients used the phrase “short of breath” to describe asthma-associated symptoms.

Conclusion

ACT item content corresponded well with the NHLBI guideline definitions of the impairment domain of asthma control (focused on asthma symptoms and impact), and we identified numerous examples in the literature indicating that ACT concepts and item content mirror the language patients use when discussing asthma symptoms and impact, and their degree of asthma control. This provides further evidence to support content validity of the ACT as a measure of asthma control.

Keywords:

• Disease management
• patient-reported outcome measures
• reproducibility of results
• content validity
• literature search

Acknowledgments

Editorial and medical writing support (in the form of writing assistance, assembling tables, collating author comments, grammatical editing, and referencing) was provided by Joanna Wilson, PhD, of Gardiner–Caldwell Communications (Glasgow, UK). Trademarks are owned by or licensed to their respective owners (the GlaxoSmithKline group of companies [VENTOLIN]; QualityMetric Incorporated [ACT]; the National Center for Biotechnology Information [PubMed]; Elsevier Ltd. [EMBASE]; Merck Sharp and Dohme Corp. [PROVENTIL]; Amphastar Pharmaceuticals, Inc. [PRIMATENE MIST]; Medicis Pharmaceutical Corp. [MAXAIR]).

Author contributions

L.M.N., L.J., and H.S. are employees of and shareholders in GlaxoSmithKline plc. R.H.S. was an employee of and shareholder in GlaxoSmithKline plc. at the time of the study, and is currently an employee of AESARA. M.K. and A.A.R. were employees of Optum at the time of the study and are now employees of QualityMetric Incorporated.

Additional information

Funding

This study was supported by GlaxoSmithKline plc. (Study HO-17-18331).