Faculty Collaboration Database

Measurement Properties of the Psoriasis Symptom Inventory Electronic Daily Diary in Patients with Moderate to Severe Plaque Psoriasis. Value Health 2017 Sep;20(8):1174-1179

Date

10/02/2017

Pubmed ID

28964451

DOI

10.1016/j.jval.2016.11.020

Scopus ID

2-s2.0-85020489769 (requires institutional sign-in at Scopus site)   9 Citations

Abstract

OBJECTIVES: The Psoriasis Symptom Inventory (PSI) is a patient-reported outcome instrument that measures the severity of psoriasis signs and symptoms. This study evaluated measurement properties of the PSI in patients with moderate to severe plaque psoriasis.

METHODS: This secondary analysis used pooled data from a phase 3 brodalumab clinical trial (AMAGINE-1). Outcome measures included the PSI, Psoriasis Area and Severity Index (PASI), static Physician's Global Assessment (sPGA), psoriasis-affected body surface area, 36-item Short-Form Health Survey version 2, and the Dermatology Life Quality Index (DLQI). The PSI was evaluated for dimensionality, item performance, reliability (internal consistency and test-retest), construct validity, ability to detect change, and agreement between PSI response and response measures based on the PASI, sPGA, and DLQI.

RESULTS: Results supported unidimensionality, good item fit, ordered responses, and PSI scoring. The PSI demonstrated reliability: baseline Cronbach's alpha ≥ 0.92 and intraclass correlation coefficients ≥ 0.95. Correlations between PSI total score and DLQI item 1 (r = 0.86), DLQI symptoms and feelings (r = 0.87), and 36-item Short-Form Health Survey version 2 bodily pain (r = -0.61) supported convergent validity. PSI scores differed significantly (P < 0.001) among severity groups based on the PASI (< 12/≥ 12), sPGA (0-1/2-3/4-5), body surface area (< 5%/5%-10%/> 10%), and DLQI (≤ 5/> 5) at weeks 8 and 12. At week 12, the PSI detected significant changes in severity based on PASI responses (< 50/50- < 75/≥ 75) and sPGA (0-1/≥ 2), and showed good agreement (k ≥ 0.66) between PSI response and PASI, sPGA, and DLQI responses.

CONCLUSION: The PSI demonstrated excellent validity, reliability, and ability to detect change in the severity of psoriasis signs and symptoms.

Author List

Viswanathan HN, Mutebi A, Milmont CE, Gordon K, Wilson H, Zhang H, Klekotka PA, Revicki DA, Augustin M, Kricorian G, Nirula A, Strober B

Author

Kenneth Brian Gordon MD Chair, Professor in the Dermatology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adult
Antibodies, Monoclonal
Antibodies, Monoclonal, Humanized
Clinical Trials, Phase III as Topic
Dermatologic Agents
Female
Health Surveys
Humans
Male
Middle Aged
Psoriasis
Quality of Life
Randomized Controlled Trials as Topic
Reproducibility of Results
Severity of Illness Index