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.

Objectives: 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.