Assessing the Importance of Treatment Goals in Patients with Psoriasis: Analytic Hierarchy Process vs. Likert Scales
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To define treatment benefit, the Patient Benefit Index contains a weighting of patient-relevant treatment goals using the Patient Needs Questionnaire, which includes a 5-point Likert scale ranging from 0 (“not important at all”) to 4 (“very important”). These treatment goals have been assigned to five health dimensions. The importance of each dimension can be derived by averaging the importance ratings on the Likert scales of associated treatment goals.
As the use of a Likert scale does not allow for a relative assessment of importance, the objective of this study was to estimate relative importance weights for health dimensions and associated treatment goals in patients with psoriasis by using the analytic hierarchy process and to compare these weights with the weights resulting from the Patient Needs Questionnaire. Furthermore, patients’ judgments on the difficulty of the methods were investigated.
Dimensions of the Patient Benefit Index and their treatment goals were mapped into a hierarchy of criteria and sub-criteria to develop the analytic hierarchy process questionnaire. Adult patients with psoriasis starting a new anti-psoriatic therapy in the outpatient clinic of the Institute for Health Services Research in Dermatology and Nursing at the University Medical Center Hamburg (Germany) were recruited and completed both methods (analytic hierarchy process, Patient Needs Questionnaire). Ratings of treatment goals on the Likert scales (Patient Needs Questionnaire) were summarized within each dimension to assess the importance of the respective health dimension/criterion. Following the analytic hierarchy process approach, consistency in judgments was assessed using a standardized measurement (consistency ratio).
At the analytic hierarchy process level of criteria, 78 of 140 patients achieved the accepted consistency. Using the analytic hierarchy process, the dimension “improvement of physical functioning” was most important, followed by “improvement of social functioning”. Concerning the Patient Needs Questionnaire results, these dimensions were ranked in second and fifth position, whereas “strengthening of confidence in the therapy and in a possible healing” was ranked most important, which was least important in the analytic hierarchy process ranking. In both methods, “improvement of psychological well-being” and “reduction of impairments due to therapy” were equally ranked in positions three and four. In contrast to this, on the level of sub-criteria, predominantly a similar ranking of treatment goals could be observed between the analytic hierarchy process and the Patient Needs Questionnaire. From the patients’ point of view, the Likert scales (Patient Needs Questionnaire) were easier to complete than the analytic hierarchy process pairwise comparisons.
Patients with psoriasis assign different importance to health dimensions and associated treatment goals. In choosing a method to assess the importance of health dimensions and/or treatment goals, it needs to be considered that resulting importance weights may differ in dependence on the used method. However, in this study, observed discrepancies in importance weights of the health dimensions were most likely caused by the different methodological approaches focusing on treatment goals to assess the importance of health dimensions on the one hand (Patient Needs Questionnaire) or directly assessing health dimensions on the other hand (analytic hierarchy process).
We thank the team of the psoriasis clinic at the University Medical Center Hamburg for their support in the patients’ recruitment and Mario Gehoff and Sara Tiedemann for copy editing this manuscript. We also thank all the patients for their participation.
MG designed and conducted the study, analyzed and interpreted study data, and drafted the manuscript. MD supported the study conception and design and data analyses, and contributed to the interpretation of data and critical revision of the manuscript. MLS contributed to the study conception and design, and critical revision of the manuscript. CG supported data analyses and contributed to the critical revision of the manuscript. MA contributed to the study conception and design, acquisition, and interpretation of data, and critical revision of the manuscript. MG acts as the guarantor for the content of the paper.
Compliance with Ethical Standards
Conflict of interest
Mandy Gutknecht has received financial support for participation in conferences from Abbvie and Astellas, and obtained honoria from Novartis. Marion Danner has no conflict of interest directly relevant to the content of this study. Marthe-Lisa Schaarschmidt conducted clinical trials for Abbvie, Boehringer Ingelheim, Celgene, Eli Lilly, Merck, Novartis, and UCB Pharma; obtained honoraria from Janssen-Cilag and Novartis; and received financial support for participation in conferences from Abbvie, ALK-Abello, Biogen, Janssen-Cilag, and MSD. Christian Gross is employed by a pharmaceutical company called Basics GmbH, which is a subsidiary of Sun Pharmaceuticals Industries Ltd. Sun Pharmaceutical Industries Ltd. sales manufactures drugs for the treatment of psoriasis. Matthias Augustin has no conflict of interest directly relevant to the content of this study.
This non-interventional study was approved by the local ethics committee (reference number: PV5182).
Consent to participate
Surveyed patients in the study gave their informed consent.
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
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