Development and validation of a patient reported outcome instrument for chronic obstructive pulmonary diseases

To develop and validate a specific patient reported outcome (PRO) for chronic obstructive pulmonary disease (COPD) patients (COPD-PRO) at a set of standardized procedures.

Literature analysis, interview and group discussion were performed to draft an initial model of COPD-PRO. Thereafter, 65 clinicians and experts throughout China reviewed the draft scale. Then cognitive debriefing interviews with 40 patients were conducted to assess respondent comprehension of the scale. After that, the revised scale was validated through pre-testing and field-testing. Finally, the psychometric properties of the COPD-PRO were evaluated by indicators such as validity, reliability and responsiveness based on the data from 230 patients.

The COPD-PRO contained 17 items in 3 domains: amelioration of clinical symptoms, satisfaction of health condition and satisfaction of treatment effect. The Cronbach's α, Split-half coefficient and test-retest coefficient were 0.806, 0.744, 0.703, respectively; the correlation coefficients between domains and overall scale were 0.835-0.963; 5 factors were extracted according to the conceptual model. The differences of the scale scores before and after treatment were statistically significant (P=0.000).

The COPDPRO has good validity, reliability and responsiveness. The COPD-PRO could provide patients' response to the treatments and then evaluate the effect of treatment in a standardized way.