A 6-item brief measure for assessing perceived control of asthma in culturally diverse patients.
BACKGROUND
A concise yet accurate measurement tool is needed for use in research and practice in asthma self-management perceptions across culturally diverse patient populations.


OBJECTIVE
To evaluate the psychometric properties of the 11-item Perceived Control of Asthma Questionnaire (PCAQ) and to derive a brief, psychometrically sound, and culturally sensitive measure using item response theory.


METHODS
The PCAQ was administered as one of a battery of measures to 375 adults with asthma as part of an ongoing larger project studying asthma disparities. Analyses of differential item functioning (DIF) were conducted to detect the effects of sex, race/ethnicity, and health literacy on psychometric properties.


RESULTS
Forty-eight percent of the sample was non-Hispanic white and 44% was African American. The mean +/- SD age was 43.7 +/- 13.7 years. The derived 6-item version, with 5 DIF items not scored, correlated highly with its full version (r = 0.903; P < .001).


CONCLUSIONS
The 6-item PCAQ short form has the potential to maintain scale integrity while reducing administration time and lessening survey fatigue in studies using multiple questionnaires. DIF analyses also enabled us to understand the unique aspects of perceived asthma control in demographic groups most affected by asthma.
Chang
Chih-Hung
CH
Buehler Center on Aging and Division of General Internal Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. chchang@northwestern.edu
Sharp
Lisa K
LK
Kimmel
Linda G
LG
Grammer
Leslie C
LC
Kee
Romina
R
Shannon
John J
JJ
D000328:Adult; D001741:Black or African American; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000517:prevention & control* / Q000523:psychology; D001519:Behavior; D032882:Comprehension; D004522:Educational Status; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012737:Sex Factors; D011795:Surveys and Questionnaires / Q000592:standards*