Background: The Living with Pulmonary Hypertension questionnaire (LPH) was adapted from the Minnesota Living with Heart Failure Questionnaire for use in patients with pulmonary arterial hypertension (PAH). Study objectives were to confirm the face and content validity, to assess the structure and psychometric properties, and provide guidance for the interpretation of the LPH.
Methods: A qualitative interview study was conducted with PAH patients in the US (n=12), Germany (n=14) and France (n=12) to evaluate the face and content validity of the LPH. Psychometric validation was performed using blinded data from a double blind, Phase III, clinical trial (n=196). Validation analyses were performed on baseline and week 12 (visit 6/last visit) data and included evaluation of: item response distributions, quality of completion, construct validity, reliability, clinical validity and responsiveness. Analyses to provide an estimation of the Minimal Important Difference (MID) for the LPH scores were performed.
Results: Cognitive debriefing interviews with 38 PAH patients indicated that the most commonly reported PAH symptoms and impacts are covered by LPH items. Patients found the LPH questionnaire relevant and comprehensive to their experience. Some suggestions were made to enhance the face validity of the LPH. The content validity of the questionnaire was supported. Results of the psychometric validation analyses (n=190) indicated that the LPH Emotional and Physical scores met the criteria for convergent and discriminant validity; for the total score all but two items met the test for item convergent validity. Internal consistency reliability was demonstrated by Cronbach's alpha values of >0.70 for all LPH scores. The LPH Physical and Total scores discriminated between World Health Organisation (WHO) Functional classes and 6 Minute walk test distances, indicating clinical validity and were also responsive to change in clinical severity, as measured by change in WHO functional class and Borg CR 10 Scale. Further investigation is required to confirm the responsiveness of the Emotional score. Estimation of MID using distribution-based methods indicated a change of 3 points for the sub-scales and 7 for the total score to be clinically meaningful.
Conclusion: The LPH is a valid and reliable instrument that meets FDA criteria.