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.
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ABSTRACT: The aim of this study is to examine the validity of the rheumatoid arthritis (RA), disease activity score (DAS), 28-C-reactive protein (CRP), the simplified disease activity index (SDAI), and the clinical disease activity index (CDAI) against the DAS28-erythrocyte sedimentation rate (ESR) and determine cut-off values for each tool in Korean patients with RA. A total of 223 RA patients were consecutively recruited from the Hanyang University Hospital for Rheumatic Diseases in Seoul, Korea. DAS28-CRP, SDAI, and CDAI were measured and compared with DAS28-ESR. The correlation coefficients of DAS28-ESR with DAS28-CRP, SDAI, and CDAI were 0.93, 0.85, and 0.84, demonstrating strong linear relationships. The cut-off values of DAS28-CRP classifying RA patients into four categories of disease activity were defined as 2.19, 2.60, and 4.07. SDAI cut-off values were defined as 3.75, 7.50, and 16.88. CDAI cut-off values were defined as 3.62, 7.38, and 16.50. DAS28-CRP, SDAI, and CDAI are valid and sensitive assessment indices of disease activity that are comparable to DAS28-ESR. The cut-off values of each tool derived in this study might be useful for routine monitoring and therapeutic decision-making in Korean RA patients.Rheumatology International 02/2011; 32(2):545-9. · 2.21 Impact Factor
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ABSTRACT: DAS28 is a widely used composite score for the assessment of disease activity in patients with rheumatoid arthritis (RA) and is often used as a treatment decision tool in the daily clinic. Different versions of DAS28 are available. DAS28-CRP(3) is calculated based on three variables: swollen and tender joint counts and CRP. DAS28-CRP(4) also includes patient global assessment. Thresholds for low and high disease activity are the same for the two scores. Based on the Bland-Altman method, the interchangeability between DAS28-CRP with three and four variables was examined in 319 RA patients selected for initiating biological treatment. Data were extracted from the Danish registry for biological treatment in rheumatology (DANBIO). Multiple regression analysis was used to assess the predictability of the DAS28 scores by several measures of disease activity. The overall mean DAS28-CRP was 4.7 ± 1.2. The mean difference between the two scores (the bias) was -0.29 ± 0.33 (CI -0.33, -0.25) (p < 0.0001). Upper and lower limits of agreement were -0.95 (CI -1.01, -0.89) and 0.37 (CI 0.31, 0.43), respectively. Tender joint count was the most important predictor of both DAS28-CRP(4) (beta = 0.52, p < 0.0001) and DAS28-CRP(3) (beta = 0.62, p < 0.0001). The second most important predictor of DAS28-CRP(4) was patient global assessment (beta = 0.32, p < 0.0001) which did not add to the prediction of DAS28-CRP(3). In conclusion, overall DAS28-CRP(3) was only slightly underestimated compared to DAS28-CRP(4). In the individual patient, however, the two scores may differ considerably. The scores should not be used interchangeably in the daily clinic without caution.Clinical Rheumatology 09/2011; 30(12):1577-82. · 2.04 Impact Factor
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ABSTRACT: OBJECTIVE: To analyze the effect of the structure of mood over the following assessment tools for rheumatoid arthritis: visual analog scale (VAS) for pain, HAQ and DAS28. PATIENTS AND METHODS: We studied 86 patients with recent onset rheumatoid arthritis, of which 75.7% were female, with a mean age at disease onset of 55 years. All patients were administered the Spanish version of the PANAS questionnaire that evaluates the components of positive (PA) and negative mood (AN). Patients belonged to the registry of new-onset arthritis in our center so clinical information was available for 282 patients visits. To determine the effect of PA and AN on each of the dependent variables we performed three multivariate linear regression models using generalized linear models through the Stata glm command 10.1. RESULTS: The mean score for PA and AN in our patients was similar to that described for the healthy Spanish population. The high scores on the subscale of AN were associated with worse scores in both the VAS for pain and the HAQ. By contrast, high scores on PA were associated with better outcomes of disease activity measured by DAS28. CONCLUSION: The structure of mood may influence the tools we use for evaluating patients with rheumatoid arthritis, so it might be advisable to include the PANAS questionnaire as part of that assessment.Reumatologia clinica. 09/2012;