Objective.: The Outcome Measures in Rheumatology (OMERACT) Ultrasound (US) Working Group (WG) operates research activities for the validation of US as an outcome measurement instrument according to the Filter 2.0 framework. Methods.: Original publications on definitions and scoring systems for pathophysiological manifestations and elementary lesions of various rheumatic disorders were reviewed from the onset of the WG research in 2005. Results.: Definitions and scoring systems according to new terminology are provided. Conclusion.: We have redefined OMERACT US pathology and elementary lesions as well as scoring systems, which are now proposed for OMERACT approval for application in clinical trials.

Objective: To estimate the prevalence of rheumatoid arthritis (RA) from international population-based studies and investigate the influence of prevalence definition, data sources, classification criteria, and geographical area on RA prevalence.Methods: A search of ProQuest, MEDLINE, Web of Science, and EMBASE was undertaken to identify population-based studies investigating RA prevalence between 1980 and 2019. Studies were reviewed using the Joanna Briggs Institute approach for the systematic review and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.Results: Sixty studies met the inclusion criteria. There was a wide range of point prevalence reported (0.00–2.70%) with a mean of 0.56% (SD 0.51) between 1986 and 2014, and a mean period prevalence of 0.51% (SD 0.35) between 1955 and 2015. RA point and period prevalence was higher in urban settings (0.69% vs 0.48%) than in rural settings (0.54% vs 0.25%). An RA diagnosis validated by rheumatologists yielded the highest period prevalence of RA and was observed in linked databases (0.80%, SD 0.1).Conclusion: The literature reports a wide range of point and period prevalence based on population and method of data collection, but average point and period prevalence of RA were 51 in 10,000 and 56 in 10,000, respectively. Higher urban vs rural prevalence may be biased due to poor case findings in areas with less healthcare or differences in risk environment. The population database studies were more consistent than sampling studies, and linked databases in different continents appeared to provide a consistent estimate of RA period prevalence, confirming the high value of rheumatologist diagnosis as classification criteria.

Objective: To evaluate the efficacy of infliximab in HLA–B27–positive patients with magnetic resonance imaging (MRI)–determined early sacroiliitis, using both clinical and MRI assessments.Methods: Forty patients with recent‐onset inflammatory back pain, as assessed by the Calin criteria, HLA–B27 positivity, clinical disease activity as measured by the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), pain and morning stiffness, and magnetic resonance imaging (MRI)–determined sacroiliac joint bone edema were randomized in a double‐blind manner to receive infliximab 5 mg/kg or placebo at 0, 2, 6, and 12 weeks. MRI scans were performed at baseline and 16 weeks and scored by 2 observers (blinded to both the order of the scans and to treatment group), using the Leeds scoring system. Clinical assessments included the BASDAI, the Bath Ankylosing Spondylitis Functional Index (BASFI), the Ankylosing Spondylitis Quality of Life (ASQoL) instrument, the ASsessment in Ankylosing Spondylitis International Working Group criteria (ASAS) for improvement, and markers of inflammation.Results: The mean reduction in the total MRI score from week 0 to week 16 was significantly greater in infliximab‐treated patients compared with placebo‐treated patients (P = 0.033). On average, significantly more lesions resolved in the infliximab group (P < 0.001), while significantly more new lesions developed in the placebo group (P = 0.004). Significantly greater improvement in the infliximab group versus the placebo group was also observed for changes from week 0 to week 16 in the BASDAI (P = 0.002), BASFI (P = 0.004), and ASQoL (P = 0.007) scores. Responses according to the ASAS criteria for 40% improvement, the ASAS criteria for 20% improvement in 5 of 6 domains, and ASAS partial remission were achieved by 61%, 44%, and 56% of infliximab‐treated patients, respectively. Infliximab was well tolerated, and no serious adverse events were observed.Conclusion: Infliximab was an effective therapy for early sacroiliitis, providing a reduction in disease activity by week 16. This study is the first to show that infliximab is effective for reducing clinical and imaging evidence of disease activity in patients with MRI‐determined early axial spondylarthritis.

Patients can fulfil clinical criteria for remission, yet still have evidence of synovitis detectable clinically and by ultrasound, and this is associated with structural damage. Stricter remission criteria may more accurately reflect true remission (no synovitis). This hypothesis was examined by studying patients using more stringent thresholds for clinical remission and determining their levels of ultrasound synovitis. Methods Rheumatoid arthritis patients with a disease activity score in 28 joints (DAS28) ≤2.6 for at least 6 months were classified using standard and more stringent DAS28 and simplified disease activity index (SDAI) remission thresholds and the corresponding clinical and ultrasound imaging measures of synovitis recorded. Results 128 patients (all DAS28 <2.6, median DAS28 1.70) receiving either disease-modifying antirheumatic drugs alone (n=66) or with a tumour necrosis factor blocker (n=62) were recruited. Of the 640 imaged joints, 5% had moderate or severe power Doppler (PD) activity, 8% were clinically swollen and 1% tender. In patients fulfilling DAS28, American College of Rheumatology or SDAI remission criteria, moderate or severe PD activity was present in 21%, 15% and 19%, respectively. More stringent DAS28 and SDAI criteria reduced the mean number of swollen and tender joints (p<0.001) but not the percentage of patients with PD activity: 32 patients had a DAS28 <1.17 but eight (25%) had significant PD activity. Conclusion Using more stringent remission criteria resulted in reduced signs and symptoms of inflammation, but the percentage of joints with PD activity was not reduced, even in those without signs or symptoms. These data suggest that clinical criteria are sufficiently insensitive to detect low but clinically relevant levels of inflammation accurately.

Objectives Combination therapy with methotrexate (MTX) and tumour necrosis factor (TNF) blockade has increased remission rates in patients with rheumatoid arthritis. However, there are no guidelines regarding cessation of therapy. There is a need for markers predictive of sustained remission following cessation of TNF blocker therapy. Methods Patients in remission (DAS28 <2.6) treated with a TNF blocker and MTX as initial or delayed therapy were recruited. Joints were assessed for grey scale synovitis and power Doppler (PD) activity. Immunological assessment involved advanced six-colour flow cytometry. Results Of the 47 patients recruited, 27 had received initial treatment and 20 delayed treatment with TNF blocking drugs. Two years after stopping TNF blocker therapy, the main predictor of successful cessation was timing of treatment; 59% of patients in the initial treatment group sustained remission compared with 15% in the delayed treatment group (p=0.003). Within the initial treatment group, secondary analysis showed that the only clinical predictor of successful cessation of treatment was shorter symptom duration before receiving treatment (median 5.5 months vs 9 months; p=0.008). No other clinical features were associated with successful cessation of therapy. Thirty-five per cent of patients had low PD activity but levels were not informative. Several immunological parameters were significantly associated with sustained remission including abnormal differentiation subset of T cells and regulatory T cells. Similar non-significant trends were observed in the delayed treatment group. Conclusion In patients in remission with low levels of imaging synovitis receiving combination treatment with a TNF blocker and MTX, immunological parameters and short duration of untreated symptoms were associated with successful cessation of TNF blocker therapy.