Development of Patient-reported Outcomes Measure of Pharmaceutical Therapy for Quality of Life (PROMPT-QoL): A novel instrument for medication management

Abstract

Background: Medicines can affect a patient's health-related quality of life (HRQoL), but there exists no standardized HRQoL measure for medication management.

Objectives: To develop the new HRQoL instrument "Patient-reported Outcomes Measure of Pharmaceutical Therapy for Quality of Life" (PROMPT-QoL), and to evaluate its content validity and preliminary psychometrics using a Rasch model.

Methods: The PROMPT-QoL questionnaire was developed through the concept review, item generation, cognitive interviews, and initial psychometric evaluation. Its first draft was initially tested by Round-1 interviews of 120 adult outpatients taking their medicines at least three months continuously. The final draft with 43 items was then constructed and checked by 10 physicians and 5 pharmacists for the questionnaire importance and content validity. Round-2 interviews in six patient groups with 10 patients of each were conducted to elicit patients' understanding of the questionnaire and assess preliminary psychometrics using the Rasch analysis, including fit statistics, person and item reliabilities.

Results: The 43-item PROMPT-QoL comprised 10 domains: General Attitude toward Medication Use, Medicine Information, Disease Information, Medicine Effectiveness, Impacts of Medicines and Side-effects, Psychological Impacts of Medication Use, Convenience, Availability and Accessibility, Therapeutic Relationship with Healthcare Providers, and Overall QoL. Based on the patient interviews and expert review, the questionnaire was considered important, useful, and comprehensive. All items and domains yielded content validity indexes above the acceptable values of 0.80 and 0.90, respectively. In Round 2, thirty-nine problems identified in Group 1 were reduced to two issues in Group 6 after amendments. The Rasch analysis revealed eight items were misfit and two domains were reliable for both personal and item aspects (Medicine Information and Psychological Impacts of Medication Use).

Conclusion: The newly developed PROMPT-QoL has favorable content validity and appropriate preliminary results. Further studies in large patient groups are required to test its complete psychometric properties.

Keywords: Medication management; Patient-reported outcomes; Pharmaceutical therapy; Quality of life; Tool development.