Dr. Ortiz has received consultant fees, speaking fees, and/or honoraria (less than $10,000 each) from Abbott, Esteve, and MSD.
Development and Validation of a New Disease Activity Index as a Numerical Sum of Four Variables in Patients With Early Arthritis
Article first published online: 28 MAR 2013
Copyright © 2013 by the American College of Rheumatology
Arthritis Care & Research
Volume 65, Issue 4, pages 518–525, April 2013
How to Cite
Castrejón, I., Carmona, L., Ortiz, A. M., Belmonte, M. A., Martínez-López, J. A. and González-Álvaro, I. (2013), Development and Validation of a New Disease Activity Index as a Numerical Sum of Four Variables in Patients With Early Arthritis. Arthritis Care Res, 65: 518–525. doi: 10.1002/acr.21854
- Issue published online: 28 MAR 2013
- Article first published online: 28 MAR 2013
- Accepted manuscript online: 22 SEP 2012 09:13AM EST
- Manuscript Accepted: 30 AUG 2012
- Manuscript Received: 28 NOV 2011
- Genoma España to the MEICA project (Molecular and Cellular Mechanisms in Chronic Inflammatory and Autoimmune Diseases)
- Fondo para la Investigación Sanitaria of the Instituto de Salud Carlos III. Grant Number: PI08/0754
To describe the development and validation of a disease activity index in early arthritis that can be easily applied in daily practice and clinical research.
The Hospital Universitario La Princesa Index (HUPI) was developed after analysis of data from an early arthritis cohort (202 patients with 756 visits). It is the sum of 4 variables (graded 0–3): tender joint count, swollen joint count, patient global assessment, and acute-phase reactants (erythrocyte sedimentation rate [ESR] and/or C-reactive protein [CRP] level, depending on availability at the moment of evaluation). The score for each variable was based on its quartile distribution in the cohort. The HUPI was validated using the following properties: feasibility, internal consistency (Cronbach's alpha), convergent validity (Pearson's r coefficients with other activity measures), criterion validity (area under the receiver operating characteristic curve [AUC ROC] to detect minimal disease activity [MDA]), and sensitivity to change (AUC ROC) to detect change with the physician's and patient's assessment of disease activity.
Internal consistency is reasonable (α = 0.63). The HUPI correlates well with activity measures such as the Disease Activity Score in 28 joints (DAS28; r = 0.89) and the Simplified Disease Activity Index (SDAI; r = 0.70), and correlates slightly worse with the functional index of the Health Assessment Questionnaire (r = 0.69). It discriminates MDA correctly (AUC 0.95), and its sensitivity to change is slightly superior (AUC 0.902) to that of the DAS28-ESR (AUC 0.864), the DAS28-CRP (AUC 0.889), and the SDAI (AUC 0.791).
The HUPI has face validity, is easy to calculate, is sensitive, and is a valid composite index for the assessment of disease activity in patients with early arthritis, both in clinical research and in routine care.