Differential influence of Clinical Disease Activity Index components based on disease state in rheumatoid arthritis patients: real-world results from the Ontario Best Practices Research Initiative
E. Keystone1, M. Movahedi2, A. Cesta3, C. Bombardier4, J.S. Sampalis5, E. Rampakakis6
- Department of Rheumatology, University of Toronto, ON, Canada. email@example.com
- Toronto General Hospital Research Institute, University Health Network, Toronto, and Institute of Health Policy, Management and Evaluation, University of Toronto, ON, Canada.
- Toronto General Hospital Research Institute, University Health Network, Toronto, ON, Canada.
- Toronto General Hospital Research Institute, University Health Network, Toronto; Department of Medicine (DMO) University of Toronto and Institute of Health Policy, Management, and Evaluation (IHPME), Toronto, and Mount Sinai Hospital, Division of Rheumatology, Toronto, ON, Canada.
- JSS Medical Research, St-Laurent, and Faculty of Medicine, McGill University, Montreal, QC, Canada.
- JSS Medical Research, St-Laurent, QC, Canada.
PMID: 35383561 [PubMed]
Accepted : 10/01/2022
In Press: 30/03/2022
The Clinical Disease Activity Index (CDAI) is routinely used in clinical care when treating-to-target RA patients. Previous validation studies have looked at CDAI’s overall performance; this analysis aimed at evaluating its properties by disease state and identifying drivers of variance.
RA patients enrolled in the OBRI registry, with available follow-up of ≥6 months were included. Construct validity of CDAI was assessed with principal component analysis; internal consistency with Cronbach’s alpha (α); correlational validity with Spearman’s rho (ρ); agreement in disease state classification with the kappa statistic. Stratification by disease states was performed.
CDAI correlation with DAS28 was strong when CDAI>10 (ρ=0.79), moderate when CDAI≤10 (ρ=0.56) or 2.8
CDAI and DAS28 correlated well in moderate/high disease activity and poorly in LDA/remission. PtGA correlated weakly with other CDAI components and had a stronger influence on CDAI in LDA/remission. Thus, careful interpretation of PtGA is necessary when making treatment decisions, particularly in patients in CDAI LDA who are non-remitters.