Jenny Humphreys Arthritis Research UK Clinical Research Fellow University of Manchester

Transcription

1 Incidence of rheumatoid arthritis in the UK using the 2010 ACR/EULAR classification criteria; and comparison with estimates using the 1987 ACR criteria Jenny Humphreys Arthritis Research UK Clinical Research Fellow University of Manchester

2 Disclosure This speaker has no conflicts of interest

3 Background Classification criteria essential

4 The ACR 1987 revised criteria for the classification of rheumatoid arthritis 1 Criterion Definition A patient is classified as RA if 4/7 criteria are satisfied. Criteria 1-4 must have been present for 6 weeks 1. Morning stiffness Morning stiffness in and around the joints, lasting at least an hour before maximal improvement 2. Arthritis of 3 joints 3 joints simultaneously have had synovitis observed ay a physician 3. Arthritis of hand joints At least 1 area swollen in a wrist, MCP or PIP joint 4. Symmetric arthritis Simultaneous involvement of the same joint areas on both sides of the body 5. Rheumatoid nodules Subcutaneous nodules, over bony prominences, extensor surfaces or juxta-articular regions 6. Serum RF Positive RF 7. Radiographic changes Radiographic changes typical of RA in posteroanterior hand and wrist radiographs 1. Arnett FC et al 1988

5 Background Classification criteria essential 1987 ACR criteria: Poor sensitivity in early disease Importance of early treatment

6 Background Classification criteria essential 1987 ACR criteria: Poor sensitivity in early disease Importance of early treatment New therapies untested in early disease

7 2010 ACR/EULAR Classification Criteria for RA 2 Target population: Patients who (i) have at least one joint with clinical synovitis, and (ii) with the synovitis not better explained by another disease Score Add score of categories A-D, score of 6/10 needed to classify patient as having definite RA A. Joint involvement (tender/swollen) 1 large joint 2-10 large joints 1-3 small joints (with or without involvement of large joints) 4-10 small joints (with or without involvement of large joints) >10 joints (at least 1 small joint) B. Serology Negative RF&ACPA Low-positive RF/low positive ACPA High positive RF/high-positive ACPA C. Acute-phase reactants Normal CRP&ESR Abnormal CRP/ESR 0 1 D. Duration of symptoms <6 weeks 6 weeks Aleteha D et al 2010

8 Background New definition new disease? What is the disease frequency?

9 Study questions What is the incidence of RA in the UK as estimated by the 2010 classification criteria? How does this compared to estimates using 1987 classification criteria? How do the criteria sets perform cumulatively?

10 Setting: Norfolk Arthritis Register (NOAR) Primary care inception cohort Adults 16 2 swollen joints 4 weeks

11 Primary care based NOAR - Strengths Stable population Mix of urban and rural Single referral point for musculoskeletal medicine

12 Incidence Incidence rate (IR) = Number of new cases of disease in specified time period Total population

13 Methods Patients with disease onset 1990 Presented to NOAR within 5 years symptom onset Denominator: Norwich health authority population 1991 census Assessments at baseline,1, 2, 3 & 5 years Both criteria sets applied at baseline & cumulatively over 5 years follow up

14 Recruitment and follow-up Baseline: Nurse led interview Demographics Symptom duration Joint examination (DAS28) HAQ Blood tests CRP, RF and ACPA Follow-up: Nurse led interview & examination HAQ Year 5: Blood test (CRP, RF & ACPA) X-rays

15 Cumulative IRs 2010 criteria: Total of highest scores for each parameter over 5 years follow up

16 2010 ACR/EULAR Classification Criteria for RA Target population: Patients who (i) have at least one joint with clinical synovitis, and (ii) with the synovitis not better explained by another disease Score Add score of categories A-D, score of 6/10 needed to classify patient as having definite RA A. Joint involvement (tender/swollen) 1 large joint 2-10 large joints 1-3 small joints (with or without involvement of large joints) 4-10 small joints (with or without involvement of large joints) >10 joints (at least 1 small joint) B. Serology Negative RF&ACPA Low-positive RF/low positive ACPA High positive RF/high-positive ACPA C. Acute-phase reactants Normal CRP&ESR Abnormal CRP/ESR 0 1 D. Duration of symptoms <6 weeks 6 weeks 0 1

17 Cumulative IRs 2010 criteria: Total of highest scores for each parameter over 5 years follow up 1987 criteria Criterion carried forward once satisfied

18 The ACR 1987 revised criteria for the classification of rheumatoid arthritis Criterion Definition A patient is classified as RA if 4/7 criteria are satisfied. Criteria 1-4 must have been present for 6 weeks 1. Morning stiffness Morning stiffness in and around the joints, lasting at least an hour before maximal improvement 2. Arthritis of 3 joints 3 joints simultaneously have had synovitis observed ay a physician 3. Arthritis of hand joints At least 1 area swollen in a wrist, MCP or PIP joint 4. Symmetric arthritis Simultaneous involvement of the same joint areas on both sides of the body 5. Rheumatoid nodules Subcutaneous nodules, over bony prominences, extensor surfaces or juxta-articular regions 6. Serum RF Positive RF 7. Radiographic changes Radiographic changes typical of RA in posteroanterior hand and wrist radiographs

19 Results

20 Baseline characteristics n=260 Age at symptom onset mean (std dev) 54 (16.2) Female n (%) 173 (69%) Symptom duration in weeks median (IQ range) 29.6 ( ) RF/ACPA positive 82 (35%) Acute phase reactant positive n (%) 120 (52%) Morning stiffness 60 mins n (%) 172 (66%) Rheumatoid nodules n (%) 19 (7%)

21 Baseline characteristics n=260 Joint involvement: n (%) 1 large joint 9 (3%) 2-10 large joints 9 (3%) 1-3 small joints 41 (16%) 4-10 small joints 52 (20%) >10 joints 149 (57%) Arthritis of 3 joints n (%) 172 (66%) Arthritis of hand joints n (%) 215 (83%) Symmetric arthritis n (%) 183 (70%)

22 Per population Baseline incidence rates (IRs)

23 Per population Baseline incidence rates (IRs) (women) 1987 (women) 2010 (men)1987 (men)

24 Per population Baseline 2010 age specific IRs (women) Age (10 yr groupings)

25 Per population Baseline 2010 & 5 year cumulative 1987 IRs (women) Age (10 yr groupings)

26 Per population Baseline 2010 age specific IRs (men) Age (10 yr groupings)

27 Per population Baseline 2010 & 5 year cumulative 1987 IRs (men) Age (10 yr groupings)

28 HOWEVER...

29 Criteria overlap Patients who satisfy 2010 criteria at baseline Patients who satisfy 1987 criteria cumulatively at 5 years n = 22 n = 35 n =145

30 Criteria overlap Patients who satisfy 2010 criteria at baseline Patients who satisfy 1987 criteria cumulatively at 5 years n = 22 n = 35 n =145 n = 58

31 Conclusions The first study to estimate incidence rates using the 2010 criteria The 2010 criteria classify more patients at initial presentation Similar rates at baseline that previous criteria take up to 5 years classify not the same patients Future work

32 Professor Deborah Acknowledgements Symmons Dr Kimme Hyrich Dr Suzanne Verstappen NOAR research nurses NOAR patients Arthritis Research UK Epidemiology Unit team

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