RESEARCH - Development of a preliminary composite disease activity index in psoriatic arthritis

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Ann Rheum Dis doi:10.1136/ard.2010.129379 Clinical and epidemiological research

Extended report

Published Online First 29 November 2010

Development of a preliminary composite disease activity index in

psoriatic arthritis

Aizad Mumtaz1, Phil Gallagher1, Kirby2, Robin Waxman3, C

Coates3, Veale J1, Philip Helliwell3, Oliver FitzGerald1

+ Author Affiliations

1Department of Rheumatology, St 's University Hospital,

University College Dublin, Dublin, Ireland

2Department of Dermatology, St 's University Hospital, Dublin,

Dublin, Ireland

3Leeds Institute of Molecular Medicine, Section of Musculoskeletal

Disease, University of Leeds, Leeds, UK

Abstract

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.

http://ard.bmj.com/content/early/2010/11/27/ard.2010.129379.abstract?papetoc

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