Are the C-reactive protein values and erythrocyte sedimentation rate equivalent when estimating the 28-joint disease activity score in rheumatoid arthritis?
ABSTRACT A formula for calculating disease activity score with 28 joint counts (DAS28) with C-reactive protein (CRP) instead of the erythrocyte sedimentation rate (ESR) has been proposed.
Here we analyze the factors that contribute to the differences in the DAS28 when calculated using either the ESR (DAS28-ESR) or the CRP values (DAS28-CRP).
We analyzed the data from 587 visits made by 220 patients with early arthritis. The age at the onset of the disease was 51+/-16 years old and 76.3% of the patients were women. The disease evolution at the first visit was 5 months and at each visit information related to several variables was collected, including that necessary to calculate the DAS28-ESR and DAS28-CRP. We defined a new variable DIFDAS=DAS28-ESR-DAS28-CRP to analyze which independent variables account for differences between the two indexes.
There was a correlation between the two indexes of 0.91 (p<0.0001), although the DAS28-ESR value obtained was higher than that of DAS28-CRP at approximately 90% of the visits. Significantly, the difference between both indexes was higher than 0.6 in 44% of the visits studied. A multivariate analysis showed that female gender and disease duration were associated with the higher values obtained for DAS28-ESR when compared to those of DAS28-CRP.
Our data show that DAS28-ESR and DAS28-CRP are not fully equivalent, because the former usually produces higher values. This finding is particularly relevant in females and patients with a long disease duration.
SourceAvailable from: Isidoro González-Álvaro[Show abstract] [Hide abstract]
ABSTRACT: Objective 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. Methods 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. ResultsInternal 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). Conclusion 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.04/2013; 65(4). DOI:10.1002/acr.21854
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ABSTRACT: Current initiatives to treat rheumatoid arthritis (RA) to target remission have resulted in the widespread use of composite outcome measures to quantify disease activity. Simplified Disease Activity Index (SDAI) ≤3.3 is the gold standard of remission. Previous work has suggested that the remission threshold of DAS28-ESR or DAS28-CRP ≤2.6 is known to be not strict enough and should be revised. There is no previous study that looks at the equivalent DAS28-CRP value that best reflects SDAI remission in a real-life cohort. Consecutive cases fulfilling ACR/EULAR classification criteria for RA from one centre were included if they had an optimum number of visits with recording of all raw data to calculate DAS28-ESR, DAS28-CRP and SDAI. Data from seven visits each of 76 patients, providing 532 data points was examined. Spearman's correlation between DAS28-ESR, DAS28-CRP and SDAI was 0.91-0.97 (p < 0.001). A Bland-Altman plot demonstrated a mean difference of 0.37 units between DAS28-ESR and DAS28-CRP (p < 0.001). ROC and kappa analysis provided values of 2.58 and 2.55 for DAS28-ESR4V and 2.09 and 2.05 for DAS28-CRP4V for SDAI value of 3.3, respectively. The two versions of DAS28 using ESR and CRP and SDAI correlate but are not equivalent or interchangeable for an individual patient. The DAS28-CRP overestimates remission and should be revised downwards to a proposed value of 2.1.Clinical Rheumatology 01/2014; DOI:10.1007/s10067-013-2468-z · 1.77 Impact Factor
Zeitschrift für Rheumatologie 06/2013; 72(5). DOI:10.1007/s00393-013-1151-8 · 0.46 Impact Factor