Abstract
Background
Psoriasis affects different aspects of health-related quality of life (eg, physical, psychological, and social impairments); these health domains can be of different importance for patients. The importance of domains can be measured with the Patient Benefit Index (PBI). This questionnaire weights the achievement of treatment goals by Likert scales (0, “not important at all” to 4, “very important”) using the Patient Needs Questionnaire (PNQ). Treatment goals assessed with the PBI have been assigned to five health domains; the importance of each domain can be calculated as the average importance of the respective treatment goals. In this study, the PBI approach of deriving importance weights is contrasted to a discrete choice experiment (DCE), in order to determine the importance of health domains in psoriasis, and to find if the resulting weights will differ when derived from these two methods.
Methods
Adult patients with psoriasis completed both questionnaires (PNQ, DCE). The PBI domains were used as attributes in the DCE with the levels “did not help at all”, “helped moderately”, and “helped a lot”.
Results
Using DCE, “improving physical functioning” was the most important health domain, followed by “improving psychological well-being”. Using PNQ, these domains were ranked in position two and three following “strengthening confidence in the therapy and in a possible healing”. The latter was least important using DCE. The only agreement of ranking was shown in “reducing impairments due to therapy” (position four). “Improving social functioning” was ranked in position three (DCE) and five (PNQ).
Conclusion
Health domains have different importance to patients with psoriasis. Using PNQ or DCE to determine the importance of domains results in markedly different rankings; both approaches can thus not be considered equivalent. However, in this study, importance was assessed at the domain level in DCE and at the single item level in PNQ, which may have added to the differences.
Supplementary material
Table S1 Comparison of patients’ judgements concerning method’s easiness to complete (n=129)
Acknowledgments
We thank the team at the Psoriasis Clinic, University Medical Center Hamburg-Eppendorf (Hamburg, Germany), for their support in patients’ recruitment and Mario Gehoff, Sara Tiedemann, and Pia Dahlhoff for copyediting this manuscript. We also thank all the patients for their participation.
Disclosure
M Gutknecht received financial support for participation in conferences from AbbVie and obtained honoraria from Novartis. ML Schaarschmidt conducted clinical trials for AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Janssen-Cilag, Merck, Novartis, and UCB Pharma; obtained honoraria from Janssen-Cilag; and received financial support for participation in conferences from AbbVie, ALK-Abello, Biogen Inc, Janssen-Cilag, and MSD. C Blome has received speaker honoraria, research grants, awards, and/or travel expenses from Celgene, Janssen-Cilag, Kreussler, Lilly, Mapi Group, Medi, Stiefel Laboratories, and Urgo. M Augustin has served as consultant and/or paid speaker for and/or has received research grants and/or honoraria for consulting and/or scientific lectures for and/or got travel expenses reimbursed and/or participated in clinical trials sponsored by companies that manufacture drugs used for the treatment of psoriasis including AbbVie, Almirall, Amgen, Biogen Idec, Boehringer Ingelheim, Celgene, Centocor, Eli Lilly, Galderma, Janssen-Cilag, Leo, Medac, MSD, Mundipharma, Novartis, Pfizer, Sandoz, and Xenoport. M Danner reports no conflicts of interest in this work.