Development of a preliminary composite disease activity index in psoriatic arthritis

• Published in: Annals of the rheumatic diseases Vol. 70; no. 2; pp. 272 - 277
• Main Authors: Mumtaz, Aizad, Gallagher, Phil, Kirby, Brian, Waxman, Robin, Coates, Laura C, Veale J, Douglas, Helliwell, Philip, FitzGerald, Oliver
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and European League Against Rheumatism 01.02.2011; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adult; Aged; Antirheumatic Agents - therapeutic use; Arthritis; Arthritis, Psoriatic - diagnosis; Arthritis, Psoriatic - drug therapy; Biological and medical sciences; Decision making; Dermatology; Diseases of the osteoarticular system; Diseases of the spine; Drug Monitoring - methods; Epidemiologic Methods; Female; Humans; Inflammatory joint diseases; Male; Medical sciences; Middle Aged; Patients; Psoriasis; Psoriasis - diagnosis; Psoriasis - drug therapy; Psoriasis. Parapsoriasis. Lichen; Quality of Life; Rheumatology; Severity of Illness Index; Skin diseases; Studies; Treatment Outcome; Validity; Spondylarthropathy; Skin disease; Chronic; Psoriasis; Activity index; Diseases of the osteoarticular system; Rheumatology; Inflammatory joint disease; Psoriatic arthritis
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/ard.2010.129379

Objectives To develop a preliminary composite psoriatic disease activity index (CPDAI) for psoriasis and psoriatic arthritis. Methods Five domains were assessed and specific instruments were employed for each domain to determine the extent of domain involvement and the effect of that involvement on quality of life/function. Disease activity for each domain was then graded from 0 to 3 giving a CPDAI range of 0–15. Patient and physician global disease activity measures were also recorded and an independent physician was asked to indicate if treatment change was required. Bivariate correlation analysis was performed. Factor, tree analysis and standardised response means were also calculated. Results Significant correlation was seen between CPDAI and both patient (r=0.834) and physician (r=0.825) global disease activity assessments (p=0.01). Tree analysis revealed that 96.3% of patients had their treatment changed when CPDAI values were greater than 6; no patient had their treatment changed when CPDAI values were less than 5. Conclusion CPDAI correlates well with patient and physician global disease activity assessments and is an effective tool that clearly distinguishes those who require a treatment change from those who do not.