Assessment of Disease Activity, Structural Damage, and Function in Rheumatoid Arthritis

The primary goal in the treatment of rheumatoid arthritis (RA) is to control disease activity, prevent structural damage in joints, and normalize function. Therefore, reliable tools are needed to disease activity, physical function, and radiographic progression in RA. We herein describe methods recently used to assess RA.

Does Pizza Consumption Favor an Improved Disease Activity in Rheumatoid Arthritis?

To our knowledge, no studies so far have investigated the role of pizza and its ingredients in modulating disease activity in rheumatoid arthritis (RA). We assessed this question via a recent cross-sectional study including 365 participants from Italy, the birthplace of pizza. Multiple robust linear and logistic regression models were fitted with the tertile consumption categories of each available pizza-related food item/group (i.e., pizza, refined grains, mozzarella cheese, and olive oil) as independent variables, and each available RA activity measure (i.e., the Disease Activity Score on 28 joints with C-reactive protein (DAS28-CRP), and the Simplified Disease Activity Index (SDAI)) as the dependent variable. Stratified analyses were carried out according to the disease severity or duration. Participants eating half a pizza >1 time/week (vs. ≤2 times/month) reported beneficial effects on disease activity, with the significant reductions of ~70% (overall analysis), and 80% (the more severe stratum), and the significant beta coefficients of -0.70 for the DAS28-CRP, and -3.6 for the SDAI (overall analysis) and of -1.10 and -5.30 (in long-standing and more severe RA, respectively). Among the pizza-related food items/groups, mozzarella cheese and olive oil showed beneficial effects, especially in the more severe stratum. Future cohort studies are needed to confirm this beneficial effect of pizza and related food items/groups on RA disease activity.

Comprehensive evaluation of the influence of sex differences on composite disease activity indices for rheumatoid arthritis: results from a nationwide observational cohort study

BACKGROUND

The effects and their magnitudes of sex on disease activity indices for rheumatoid arthritis are not clear. We aimed to comprehensively evaluate the influence of sex on disease activity indices in the real-world setting using a large observational database.

METHODS

We analyzed 14,958 patients registered in the National Database of Rheumatic Diseases in Japan (NinJa) in 2017. We evaluated the sex differences in the 28-joint disease activity score (DAS28) using erythrocyte sedimentation rate (ESR), DAS28 using C-reactive protein (DAS28-CRP), Simplified Disease Activity Index (SDAI), and Clinical Disease Activity Index by disease activity category using Cliff's delta and regression analysis. Differences in the share of components of indices were evaluated using permutational multivariate analysis of variance. Correction equations were constructed to estimate the number of misclassification in male patients who achieve DAS28-ESR remission.

RESULTS

DAS28-ESR showed higher values in female patients than male patients in remission despite no obvious difference in other indices or disease activity categories. Among the components of DAS28-ESR, only ESR was higher in female patients than male patients in remission. In DAS28-CRP and SDAI, 28-tender joint count was higher and CRP was lower in female patients than male patients. In addition, the profiles in the components were different between female and male patients, especially among those with high disease activity. Using correction equations, almost 12% of male patients with DAS28-ESR remission were estimated to be misclassified, mainly due to differences in ESR.

CONCLUSION

Among the disease activity indices, significant sex difference was observed only in DAS28-ESR remission. The degree of misclassification in DAS28-ESR remission would be unignorable.

Olive Oil and Nuts in Rheumatoid Arthritis Disease Activity

Few observational studies investigated the relationship between single food groups and disease activity in rheumatoid arthritis (RA). Within a recent Italian cross-sectional study (365 patients, median age: 58.46 years, 78.63% females), we focused on two food groups, olive oil and nuts, representing vegetable sources of fatty acids. Disease activity was measured with Disease Activity Score on 28 joints based on C-reactive protein (DAS28-CRP) and the Simplified Disease Activity Index (SDAI). Robust linear and logistic regression models included tertile-based consumption categories of each food group and several confounders. Stratified analyses were performed by disease severity or duration. Higher consumption of both food groups exerted a favorable effect on disease activity, significant only for olive oil (Beta: -0.33, p-value: 0.03) in the linear regression on the overall sample. This favorable effect was stronger in the more severe or long-standing forms of RA (p-value for heterogeneity <0.05, especially for disease severity). Significant ORs were as low as ~0.30 for both food groups, strata (i.e., more severe and long-standing RA), and disease activity measures. Mean DAS28-CRP significantly decreased by ~0.70 for olive oil and ~0.55 for nuts in the two strata; mean SDAI significantly decreased by 3.30 or more for olive oil in the two strata. Globally, the beta coefficients doubled, and the ORs halved (in absolute values) for both food groups, reaching significance in 12 of the 16 available models fitted to the more severe or long-standing RA strata. More compromised forms of RA may benefit from increasing consumption of olive oil, olives, and nuts.

A systematic comparison of different composite measures (DAS 28, CDAI, SDAI, and Boolean approach) for determining treatment effects on low disease activity and remission in rheumatoid arthritis

BACKGROUND

Some composite measures for determining the treatment effects of disease-modifying antirheumatic drugs on remission and low disease activity (LDA) in rheumatoid arthritis (RA) may produce misleading results if they include an acute phase reactant (APR). To inform the choice of appropriate measure, we performed a systematic comparison of treatment effects using different composite measures.

METHODS

We used data generated for a systematic review of biologics in RA conducted by the Institute for Quality and Efficiency in Health Care and data from systematic reviews of newer biologics and Janus kinase (JAK) inhibitors provided by sponsors. The studies included had been conducted up to 2020 and investigated comparisons of biologics with placebo and head-to-head comparisons of biologics. Treatment effects on LDA and remission in studies investigating biologics or JAK inhibitors in RA were compared among 4 composite measures: the disease activity score 28 (DAS 28), the simplified disease activity index (SDAI), the Boolean approach (remission only), and the clinical disease activity index (CDAI)-only the latter does not include an APR.

RESULTS

49 placebo-controlled studies included 9 different biologics; 48 studies (16,233 patients) investigated LDA and 49 (16,338 patients) investigated remission. 11 active-controlled studies (5996 patients) investigated both LDA and remission and included 5 different head-to-head comparisons of biologics and 5 different comparisons (6 studies) of biologics with JAK inhibitors. Statistically significantly larger treatment effects were found for biologics or JAK inhibitors versus placebo or active control in 16% of pairwise comparisons of composite measures (27 of 168). Most of these larger effects were observed for composite measures with an APR, i.e. the DAS 28 (19 comparisons) followed by the SDAI (n = 7). Larger effects were most frequently detected in favour of interleukin (IL)-6 inhibitors and to a lesser extent for JAK inhibitors versus treatments with different modes of action.

CONCLUSIONS

The use of the DAS 28 and SDAI in clinical studies may generate results favouring certain treatments based on their mode of action (e.g. IL-6 inhibitors versus other biologics). To enable unbiased comparative effectiveness research, a composite measure without an APR (i.e. the CDAI) should thus be the measure of choice.

Development and validation of equations for conversion from DAS28ESR and DAS28CRP to the SDAI in patients with rheumatoid arthritis

INTRODUCTION

Disease Activity Score-28 (DAS28) with erythrocyte sedimentation rate (DAS28ESR), DAS28 with C-reactive protein (DAS28CRP), and simplified disease activity index (SDAI) are widely used to assess disease activity as low, moderate, or high or in remission in patients with rheumatoid arthritis (RA). However, these indicators can generate inconsistent results, influencing treatment decisions and limiting comparisons across studies. We aimed to establish equations for conversion from DAS28ESR and DAS28CRP to SDAI.

METHODS

We conducted a retrospective study, including 933 outpatients who were simultaneously assessed using DAS28ESR, DAS28CRP, and SDAI. The patients were divided into a training set (70%) and a validation set (30%). We developed equations to convert DAS28ESR and DAS28CRP values into SDAI values by bisquare-weighted robust regression to obtain SDAI-DAS28ESR and SDAI-DAS28CRP. In addition to using kappa values to assess consistency, differences in disease activity classification between SDAI-DAS28ESR and SDAI-DAS28CRP were examined by the Stuart-Maxwell test and the Bowker test.

RESULTS

Two quadratic equations were developed as follows: SDAI-DAS28ESR = 1.168 × (DAS28ESR)^2 - 2.432 × (DAS28ESR) + 2.649 and SDAI-DAS28CRP = 1.2 × (DAS28CRP)^2 - 0.3522 × (DAS28CRP) - 0.6014. After applying the equations, the Stuart-Maxwell test and the Bowker test were no longer significant between SDAI-DAS28ESR and SDAI or between SDAI-DAS28CRP and SDAI. The kappa values increased from 0.57 to 0.73 between SDAI-DAS28ESR and SDAI and 0.76 to 0.86 between SDAI-DAS28CRP and SDAI.

CONCLUSION

SDAI-DAS28ESR and SDAI-DAS28CRP are interchangeable with the SDAI on the group level, which will facilitate comparisons among studies. In addition, the equations improved consistency between indicators. Key Points • There is disagreement in assessing disease activity in patients with rheumatoid arthritis between Disease Activity Score-28 (DAS28) with erythrocyte sedimentation rate (DAS28ESR), DAS28 with C-reactive protein (DAS28CRP), and simplified disease activity index (SDAI). • We developed and validated two quadratic equations to convert DAS28ESR and DAS28CRP into SDAI. We found there was no longer significant difference in disease activity between indicators after applying the equations. • This work may allow comparisons across studies which use different indicators.

Validation of the Simplified Disease Activity Index (SDAI) with a quick quantitative C-reactive protein assay (SDAI-Q) in patients with rheumatoid arthritis: a prospective multicenter cross-sectional study

Objectives:

The Simplified Disease Activity Index (SDAI) is a recommended composite score for assessing the remission status in patients with rheumatoid arthritis (RA). However, determination of C-reactive protein (CRP) levels takes several hours and sometimes days and limits the use of the SDAI in the clinical setting. The aim of this study was to validate the SDAI using a quick quantitative C-reactive protein (qCRP) assay (as SDAI-Q) in RA patients.

Design:

This is a multicenter, prospective, cross-sectional pilot study in RA patients.

Methods:

Adult patients (⩾18 years) with a clinical diagnosis of RA were recruited between January 2020 and September 2020 from five rheumatologic centers located in Berlin, Germany. SDAI, SDAI-Q, Clinical Disease Activity Index (CDAI), and DAS28 scores comprising CRP, qCRP, or erythrocyte sedimentation rate (ESR) were calculated. The agreement of disease activity categories was analyzed using cross tabulations and weighted Cohen’s kappa. The agreement of numerical values was analyzed with Bland–Altman plots and intraclass correlation coefficients (ICCs).

Results:

Overall, 100 RA patients were included in the statistical analysis. The mean value of qCRP (7.89 ± 16.98 mg/l) was slightly higher than that of routine laboratory CRP (6.97 ± 15.02 mg/l). Comparing SDAI and SDAI-Q, all patients were assigned to identical disease activity categories. Agreement of disease activity categories by CDAI and SDAI/SDAI-Q was observed in 93% with a weighted Cohen’s kappa of 0.929 (95% confidence interval (CI) = 0.878; 0.981).

Conclusion:

The SDAI-Q showed an absolute agreement regarding the assignment of disease activity categories in comparison with the conventional SDAI. Therefore, the SDAI-Q may facilitate the application of a treat-to-target concept in clinical trials and clinical routine as a quickly available disease activity score incorporating CRP as an objective parameter.

A Posteriori Dietary Patterns and Rheumatoid Arthritis Disease Activity: A Beneficial Role of Vegetable and Animal Unsaturated Fatty Acids

To our knowledge, no studies have investigated the relationship between a posteriori dietary patterns (DPs)-representing current dietary behavior-and disease activity in patients with rheumatoid arthritis (RA). We analyzed data from a recent Italian cross-sectional study including 365 RA patients (median age: 58.46 years, 78.63% females). Prevalent DPs were identified through principal component factor analysis on 33 nutrients. RA activity was measured according to the Disease Activity Score on 28 joints (DAS28) and the Simplified Disease Activity Index (SDAI). Single DPs were related to disease activity through linear and logistic regression models, adjusted for the remaining DPs and confounders. We identified five DPs (~80% variance explained). Among them, Vegetable unsaturated fatty acids (VUFA) and Animal unsaturated fatty acids (AUFA) DPs were inversely related to DAS28 in the overall analysis, and in the more severe or long-standing RA subgroups; the highest score reductions (VUFA: 0.81, AUFA: 0.71) were reached for the long-standing RA. The SDAI was inversely related with these DPs in subgroups only. This Italian study shows that scoring high on DPs based on unsaturated fats from either source provides independent beneficial effects of clinical relevance on RA disease activity, thus strengthening evidence on the topic.

Clinical conditions needed to acquire sustained functional remission in rheumatoid arthritis patients

OBJECTIVES

Treatments aimed at maintaining sustained clinical remission in rheumatoid arthritis (RA) patients have been recommended by several groups. Improvement and maintenance of functional status are also important for RA patients. The purpose of this study was to investigate the factors for maintaining long-term functional remission.

METHODS

RA patients with usual care without specific protocols were included. Disease activity score using 28-joint count C-reactive protein (DAS28-CRP), simplified disease activity index (SDAI) score, and Health Assessment Questionnaire Disability Index (HAQ-DI) score was calculated every 3 months for 1 year. Patients were divided into the HAQ-DI remission (REM) group and the HAQ-DI non-remission (NO-REM) group; time-averaged values of these parameters were compared between groups.

RESULTS

Of the 205 patients, 154 fulfilled the remission criteria. Time-averaged DAS28-CRP and SDAI score were significantly lower in the REM group than in the NO-REM group (1.66 vs 2.59, 3.54 vs 10.68, respectively; p < 0.001). Subsequent receiver-operating characteristic (ROC) analysis for estimation of remission indicated a cut-off value of 1.65 for time-averaged DAS28-CRP and 2.85 for time-averaged SDAI score.

CONCLUSIONS

Previous reports showed that fulfillment of clinical remission increases the possibility of functional remission; the probability of which is higher in patients with sustained clinical remission. Sustained clinical remission is required to achieve sustained functional remission; the criteria for clinical remission may be more stringent. Key Points • Sustained deep clinical remission was required to achieve sustained functional remission.

Disease activity measures at baseline predict structural damage progression: data from the randomized, controlled AMPLE and AVERT trials

Objective

Data from two double-blind, randomized, Phase III studies were analysed to investigate the ability of Routine Assessment of Patient Index Data 3, DAS28 (CRP), modified (M)-DAS28 (CRP) and Simplified or Clinical Disease Activity Indices to predict structural damage progression in RA.

Methods

This post hoc analysis included data from the 2-year Abatacept vs adaliMumab comParison in bioLogic-naïvE RA subjects with background MTX (AMPLE) trial in biologic-naïve patients with active RA (<5 years) and an inadequate response to MTX, and the 12-month treatment period of the Assessing Very Early Rheumatoid arthritis Treatment (AVERT) trial in MTX-naïve patients with early RA (⩽2 years) and poor prognostic indicators. Adjusted logistic regression analysis assessed the relationship between baseline disease activity and structural damage progression (defined as change from baseline greater than the smallest detectable change) at 12 and 24 months in AMPLE and 6 and 12 months in AVERT. Areas under the receiver operating characteristic curves for the impact of baseline disease activity on structural damage progression were calculated.

Results

Adjusted logistic regression analyses included all randomized and treated patients in AMPLE (N = 646) and those who received abatacept plus MTX or MTX monotherapy in AVERT (N = 235). Baseline Routine Assessment of Patient Index Data 3, DAS28 (CRP) and M-DAS28 (CRP) scores significantly predicted structural progression at months 12 and 24 in AMPLE (P < 0.05) and months 6 and 12 in AVERT (P < 0.01), and were stronger predictors than Simplified or Clinical Disease Activity Indices.

Conclusion

In this post hoc analysis of two patient populations with RA, Routine Assessment of Patient Index Data 3, DAS28 (CRP) and M-DAS28 (CRP) were good at predicting structural damage.

Trial registration

ClinicalTrials.gov, http://clinicaltrials.gov: NCT00929864 (AMPLE); NCT01142726 (AVERT).

Differences in disease activity measures in patients with rheumatoid arthritis who achieved DAS, SDAI, or CDAI remission but not Boolean remission

OBJECTIVES

In patients with rheumatoid arthritis (RA), remission may be assessed by various composite measures. We assessed achievement of remission as defined by Boolean criteria, Simplified Disease Activity Index (SDAI), Clinical Disease Activity Index (CDAI), and 28-joint Disease Activity Score using C-reactive protein (DAS28[CRP]) and determined the components that limit patients in SDAI, CDAI, or DAS28(CRP) remission from achieving Boolean remission.

METHODS

The proportions of patients achieving Boolean, SDAI, CDAI, or DAS28(CRP) remission were calculated for 3 trials: PREMIER and OPTIMA in patients with early RA and DE019 in patients with established RA. At the first visit that remission was recorded during the first 52 weeks of the trial, the following were assessed: swollen/tender joint count at 28 and 66/68 joints, CRP, Patient's/Physician's Global Assessment (PGA/PhGA), SDAI, DAS28(CRP), and Health Assessment Questionnaire-Disability Index.

RESULTS

The majority of patients (61-66%) who achieved SDAI or CDAI remission also attained Boolean remission. Although DAS28(CRP) remission was most frequently attained, 74-77% of patients in DAS28(CRP) remission did not achieve Boolean remission. Compared with patients in Boolean remission, patients in SDAI or CDAI remission but not Boolean remission had higher PGA scores, while patients with DAS28(CRP) remission but not Boolean remission had higher joint counts, and PGA and PhGA scores.

CONCLUSIONS

Differences in PGA limit patients in SDAI/CDAI remission from meeting the Boolean remission criteria, suggesting that these criteria otherwise can be used interchangeably. In contrast, patients in DAS28(CRP) remission are limited by differences in multiple disease activity measures from achieving Boolean remission.

Predictors and the optimal duration of sustained remission in rheumatoid arthritis

OBJECTIVE

To determine predictors and optimal duration of sustained remission (SR) in patients with rheumatoid arthritis (RA).

METHODS

A total of 428 consecutive patients with RA visiting our clinic routinely between 2012 and 2013 were evaluated. Seventy seven of these patients in DAS28 remission were enrolled and followed up for 62.2 ± 9.9 months. Patients in remission ≥ 6 months (SR) and shorter (non: N-SR) were compared in terms of demographic-clinical data and the psychosocial factors. At enrollment, 1st and 5th years, patients in DAS28, SDAI, and Boolean remission were determined.

RESULTS

Sixty three patients were in SR and 14 in N-SR. Lower baseline DAS28 and HAQ scores, anti-CCP were positive predictors of SR. Although the presence of anxiety, depression, fibromyalgia, and fatigue were lower in the SR group, there was no significance. Patients in DAS28 remission (100%) at baseline reduced to 64% at 1st and 42.6% at 5th years. Patients satisfying SDAI and Boolean remission at these three visits were 49%, 44%, and 32.4% vs 41%, 28%, and 20.6%, respectively. If the duration of remission is defined as 6 months, the remission rates of SDAI at inclusion and fifth years' visits were similar but Boolean remission rates differed significantly and if it is accepted as ≥ 12 months, both the SDAI and Boolean remission rates were not different.

CONCLUSION

Low DAS28 and HAQ scores at baseline, anti-CCP were positive predictors of SR. Instead of 6 months, remission duration for ≥ 12 months would probably help us to predict SR independently from the chosen criteria; Boolean or SDAI.

Azilsartan improves the effects of etanercept in patients with active rheumatoid arthritis: a pilot study

Background and aim

Much evidence has emerged documenting the involvement of the renin-angiotensin system (RAS) in inflammatory processes. The objective of this study was to evaluate the effects of blocking RAS with azilsartan (Azil) on the clinical efficacy of etanercept (Etan) in patients with active rheumatoid arthritis (RA).

Patients and methods

Forty-two patients diagnosed with active RA and poorly responding to methotrexate were enrolled in this pilot clinical study. They were randomly allocated into two groups, and treated with either Etan (50 mg/week) and placebo or the same dose of Etan with Azil (20 mg/day) for 90 days. The clinical outcome was evaluated using the Disease Activity Score-28 joint (DAS-28), simplified disease activity index (SDAI), clinical disease activity index (CDAI) and the health assessment questionnaire disease index (HAQ-DI). Blood samples were obtained for the assessment of C-reactive protein and erythrocyte sedimentation rate at baseline and after 90 days.

Results

The markers of pain and disease activity, C-reactive protein and erythrocyte sedimentation rate were significantly improved when Azil was used, as an adjuvant with Etan, compared with the use of Etan and placebo.

Conclusion

Blocking RAS with azilsartan may improve the effects of etanercept on the clinical markers of pain and disease severity of patients with active RA not responding to methotrexate.

Predictor of the Simplified Disease Activity Index 50 (SDAI 50) at Month 3 of bDMARD Treatment in Patients with Long-Established Rheumatoid Arthritis

Objectives:

The Simplified Disease Activity Index (SDAI) 50 has good agreement with European League Against Rheumatism (EULAR) response measures for early Rheumatoid Arthritis (RA). There have been reports on early RA, but not on long-established RA. In this study, we analysed the relationships between various baseline factors and SDAI 50 after three months of treatment with biological disease-modifying antirheumatic drugs (bDMARDs) to determine the prognostic factors for long-established RA.

Methods:

Subjects were 260 RA patients who had been treated with bDMARDs for 3 months. The following characteristics were investigated: Patient backgrounds, the erythrocyte sedimentation rate (ESR), C-reactive protein and serum matrix metalloproteinase-3 levels, SDAI scores, and health assessment questionnaire disability index and short form-36 scores. As a primary outcome index, the SDAI response was defined as a 50% reduction in the SDAI score between baseline and 3 months (SDAI 50).

Results:

Baseline values of disease duration (odds ratio: 0.942, 95% CI: 0.902-0.984), smoking history (odds ratio: 2.272, 1.064-4.850), 28-tender joint count (odds ratio: 0.899, 0.827-0.977), evaluator's global assessment (odds ratio: 1.029, 1.012-1.047) and ESR (odds ratio: 1.015, 1.001-1.030) were determined to be significant factors based on logistic regression analysis.

Conclusion:

Our study demonstrated that RA patients with shorter disease duration, no smoking, and higher RA disease activity are more likely to achieve SDAI 50 through bDMARD treatment.

Assessment of Disease Activity, Structural Damage, and Function in Rheumatoid Arthritis

The primary goal in the treatment of rheumatoid arthritis (RA) should be achieving control of disease activity, prevention of structural damage in joints, and normalization of function. Therefore, reliable tools are necessary to evaluate RA. Here, we describe methods recently used to assess RA.

Comparison of composite indices with global synovitis score on ultrasound for detecting remission

We aimed to compare composite indices with Ultrasound Global Synovitis Score (GLOESS) for remission in rheumatoid arthritis (RA). RA patients in remission according to the clinician were investigated with Disease Activity Score28 (DAS28), Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI), and RAPID-3 (Routine Assessment of Patient Index Data 3). Ultrasonography was performed using the GLOESS scores. Patients in CDAI-remission had lower GLOESS (median (IQR), 5(3-9.75) vs 7(4-11.75), p = 0.048) with a similar trend in SDAI (5(3-9.25) vs 7(4-11.25), p = 0.064). This was not observed with DAS28-CRP and RAPID3. Our results show that CDAI is superior to other indices to assess remission in RA.

Correlation between rapid-3, DAS28, CDAI and SDAI as a measure of disease activity in a cohort of Colombian patients with rheumatoid arthritis

The objective of this study is to correlate the patient-driven tool Routine Assessment of Patient Index Data 3 (RAPID-3) with other common tools used in daily practice to measure disease activity in rheumatoid arthritis (RA).One hundred nineteen RA patients according to 1987 American College of Rheumatology criteria who consecutively attended a RA outpatient clinic between August and December 2015 were evaluated. Data was stored in an electronic form that included demographic information, comorbidities, concomitant medication, and laboratory results. The disease activity was determined by tender and swollen joint count, pain and disease activity visual analog scales (VAS), disease activity score 28 (DAS28), Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI), and multidimensional health assessment questionnaire (MDHAQ). Correlations between RAPID-3 and other disease activity tools were assessed. Mean age was 61 ± 13.8 years with a median disease duration of 14 years (IQR 5-21), 77% were females. Median scores were MDHAQ 0.5 (IQR 0.1-1.2), DAS 28 3.8 (IQR 2.7-5.1), and RAPID-3 12.3 (IQR 6-19). A strong correlation was obtained between RAPID-3 and DAS 28 (r 0.719, p < 0.001), CDAI (r 0.752, p < 0.001), and SDAI (r 0.758, p < 0.001). RAPID-3 had a high correlation with tools regularly used for disease activity assessment of RA patients in daily practice. The ease of its application favors routine use as it does not require laboratory results and joint counts.