Validation of the Onset of Effect Questionnaire in Participants With Chronic Obstructive Pulmonary Disease

Background: Patient perception of medication onset of effect is important for adherence. Although the Onset of Effect Questionnaire (OEQ) has been validated in patients with asthma, it has not been evaluated in patients with chronic obstructive pulmonary disease (COPD). This study evaluated the COPD-OEQ in patients with COPD.

Methods: Two analyses (qualitative and quantitative) were conducted to assess the content validity and psychometric properties of the COPD-OEQ in participants with COPD. In the qualitative analysis, interviews assessed content validity by concept elicitation (CE) and cognitive interviewing (CI). CE included questions to understand patient experience related to onset of medication effect. CI included completion of the COPD-OEQ and assessment of the COPD-OEQ items, response options, and instructions. During the 2-week quantitative analysis, 2 versions of the COPD-OEQ (Weekly and Daily) were administered to assess test-retest reliability, construct validity, and known-groups validity.

Results: The qualitative analysis demonstrated that 3 of the 5 COPD-OEQ items were relevant and understood as intended. Qualitative findings demonstrated inconsistent evidence that the COPD-OEQ Weekly and Daily were reliable and valid measures in participants with COPD. Test-retest reliability was observed for the COPD-OEQ Weekly and Daily; however, construct validitywas weak and demonstrated inconsistent correlations among COPD-OEQ items. Overall, known-groups validity was not demonstrated.

Conclusion: The weak evidence from the quantitative analysis of the COPD-OEQ Weekly and Daily tools does not support use of the OEQ in general COPD. The study supports the content validity for the assessment of perceived onset of effect in patients with COPD.