Session Information
Title: Rheumatoid Arthritis - Clinical Aspects (ACR): Comorbidities, Treatment Outcomes and Mortality
Session Type: Abstract Submissions (ACR)
Background/Purpose:
Correct identification of the subset of patients with undifferentiated arthritis (UA) who will develop rheumatoid arthritis (RA) is important to enable initiation of appropriate treatment. Our objectives were to compare baseline characteristics and treatment of UA patients developing vs. not developing RA according to the 2010 ACR/EULAR RA classification criteria (UA-RA vs. UA-non RA) over a 2-year follow-up period, and to investigate the relationship between clinical RA diagnosis and fulfilment of the RA criteria in these patients.
Methods:
Patients (18-75 years old) with ≥1 swollen joint of ≤16 weeks duration were from 2004 included in a multi-center longitudinal observational study and followed for 2 years with examinations at 0, 3, 6, 12 and 24 months. Patients with arthritis due to trauma, septic arthritis, crystal arthritis and osteoarthritis were excluded. Mann-Whitney U test, independent samples T test and chi-square test were used to compare baseline characteristics between UA-non-RA and UA-RA patients.
Results:
1119 patients were included during the period 2004-2010 (mean (SD) age 46(15) years, 55% females, median ((25, 75 perc) duration of joint swelling 34(13, 66) days). Patients with a clinical diagnosis of a rheumatic disease other than RA, and those without available anti-CCP/RF or follow-up data were excluded. Consequently, 663 patients were eligible for the current analyses, and 250 (37%) of these patients fulfilled the 2010 ACR/EULAR RA classification criteria at baseline. Among the remaining 413 patients, who were denoted UA, 27 patients (7%) were classified as RA during follow-up. 21/27 (78%) of these UA-RA patients fulfilled the criteria within the first 6 months. 58/386 patients (15%) of patients started DMARDs (3 patients started biologics for diagnosis of AS, RA and UA, respectively) vs. 16/27 (59%) in the UA-RA group (3 patients on biologics, all with clinical RA diagnosis) (p<0.001). In both groups approx. 2/3 of those started on DMARDs did so within the first 3 months and were mostly started on methotrexate. 22/386 (6%) of all the UA-non-RA were given a clinical diagnosis of RA during follow-up (19 of these patients were anti-CCP and RF negative).
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Comparison of baseline characteristics between the UA-non-RA and UA-RA patients
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UA-non-RA (n=386)
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UA-RA (n=27)
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P-value
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Age, mean (SD)
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46.6 (14.8)
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51.3 (13.8)
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0.11
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Female gender, n (%)
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207 (53.6)
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20 (74.1)
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0.039
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Duration of joint swelling, days, median (25, 75 perc.)
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31 (10,66)
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30 (14,60)
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0.75
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Body mass index, mean (SD) |
25.9 (4.4)
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26.2 (4.4)
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0.707
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Smoker ever, n (%) |
214 (55.7)
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21 (77.8)
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0.09
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RF and/or ACPA positive, n (%)
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15 (3.9)
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10 (37.0)
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<0.001
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Small joint involvement, n (%) |
168 (43.5)
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12 (55.6)
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0.049
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Shoulder involvement, n (%)
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5 (1.3)
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4 (14.8)
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0.001
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Ankle involvement, n (%)
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74 (19.2)
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1 (3.7)
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0.04
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ESR, mm/h, median (25,75 perc.) |
18 (9,36)
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23 (3,28)
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0.42
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CRP, mg/L median (25,75 perc)
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10 (8,38)
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8 (3,21)
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0.96
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68-SJC*, median (25,75 perc.)
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1 (1,3)
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2 (1,6)
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0.005
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28-TJC, median (25,75 perc.)
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1 (0,2)
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2 (1,5)
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<0.001
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Assessor global VAS, mean (SD)
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29.2 (16.7)
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37.6 (18.3)
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0.012
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Patient global VAS, mean (SD)
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50.6 (24.2)
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62.4 (22.9)
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0.015
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DAS 28, mean (SD)
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3.5 (1.0)
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4.3 (1.0)
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<0.001 |
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HAQ, mean (SD)
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0.69 (0.58)
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1.17 (0.80)
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<0.001 |
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Criteria points, median (25,75 perc.)
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2 (1,4)
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4 (3,5)
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<0.001 |
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Criteria points distribution
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5 points
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n=21
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n=11
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<0.001 |
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4 points
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n=80
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n=7
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3 points
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n=83
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n=6
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2 points
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n=73
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n=0
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1 point
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n=99
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n=2
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0 points
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n=30
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n=1
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*Standard 66-swollen joint count plus hips
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Conclusion:
Among 413 patients with UA of ≤16 weeks duration only 7% fulfilled the 2010 RA classification criteria during 2 years of follow-up. Female gender, positive RF and/or ACPA, shoulder arthritis and number of involved joints were among the factors associated with RA development while ankle arthritis was more common in UA-non-RA patients. Some patients (mostly RF and/or ACPA negative) were given a clinical diagnosis of RA despite not fulfilling the criteria, but the proportion was low (6%).
Disclosure:
G. H. Brinkmann,
None;
E. S. Norli,
None;
T. K. Kvien,
None;
A. J. Haugen,
None;
L. Grøvle,
None;
H. Nygaard,
None;
C. Thunem,
None;
M. D. Mjaavatten,
None;
E. Lie,
AbbVie,
5,
UCB,
5,
Hospira,
5,
BMS,
5,
Pfizer Inc,
5.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/disease-characteristics-and-ra-development-in-undifferentiated-arthritis-a-2-year-follow-up-study-of-413-patients-with-arthritis-of-less-than-16-weeks-duration/