The worldwide prevalence of psoriatic arthritis-a systematic review and meta-analysis.

OBJECTIVES: Previous attempts to pool prevalence studies in PsA have failed to take account of important methodological differences between studies which may have created biased estimates. The aim of this review is to estimate the prevalence of PsA within the adult general population worldwide, considering potential differences between population-based and health administrative studies separately. METHODS: Four electronic databases were systematically searched for articles reporting the prevalence of PsA. Data were pooled to generate worldwide prevalence estimates. Where sufficient data were available, results were summarised by continent. RESULTS: 30 studies were identified, with half from Europe (n = 15). Thirteen population-based studies were identified comprising >92 000 adults, plus 17 studies (>180 million adults) based on health administrative data. The worldwide prevalence of PsA was 112 per 100 000 adults. The prevalence of PsA estimated using populations-based studies was 113 per 100 000 with continent-specific estimates of 207 (Europe), 64 (North America), and 37 (Asia) per 100 000. Health administrative studies gave a global prevalence of 109 per 100 000 with continent-specific prevalence of 175 (Europe), 147 (North America), 78 (Asia), and 17 (South America). CONCLUSION: This review compiles currently available estimates of PsA prevalence in the general population into global and continent-based estimates and considers important study design characteristics. There is wide variability between continents and data in some geographical areas are sparse but available evidence suggests that PsA is more common in Europe and North America compared with Asia and South America, and current best estimates suggest a global prevalence of 112 per 100 000 adults.

Cut-Offs for Disease Activity States in Axial Spondyloarthritis With Ankylosing Spondylitis Disease Activity Score (ASDAS) Based on C-Reactive Protein and ASDAS Based on Erythrocyte Sedimentation Rate: Are They Interchangeable?

OBJECTIVE: Ankylosing Spondylitis Disease Activity Score based on C-reactive protein (ASDAS-CRP) is recommended over ASDAS based on erythrocyte sedimentation rate (ASDAS-ESR) to assess disease activity in axial spondyloarthritis (axSpA). Although ASDAS-CRP and ASDAS-ESR are not interchangeable, the same disease activity cut-offs are used for both. We aimed to estimate optimal ASDAS-ESR values corresponding to the established ASDAS-CRP cut-offs (1.3, 2.1, and 3.5) and investigate the potential improvement of level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states when applying these estimated cut-offs. METHODS: We used data from patients with axSpA from 9 European registries initiating a tumor necrosis factor inhibitor. ASDAS-ESR cut-offs were estimated using the Youden index. The level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states was compared against each other. RESULTS: In 3664 patients, mean ASDAS-CRP was higher than ASDAS-ESR at both baseline (3.6 and 3.4, respectively) and aggregated follow-up at 6, 12, or 24 months (1.9 and 1.8, respectively). The estimated ASDAS-ESR values corresponding to the established ASDAS-CRP cut-offs were 1.4, 1.9, and 3.3. By applying these cut-offs, the proportion of discordance between disease activity states according to ASDAS-ESR and ASDAS-CRP decreased from 22.93% to 19.81% in baseline data but increased from 27.17% to 28.94% in follow-up data. CONCLUSION: We estimated the optimal ASDAS-ESR values corresponding to the established ASDAS-CRP cut-off values. However, applying the estimated cut-offs did not increase the level of agreement between ASDAS-ESR and ASDAS-CRP disease activity states to a relevant degree. Our findings did not provide evidence to reject the established cut-off values for ASDAS-ESR.

European bio-naïve spondyloarthritis patients initiating TNF inhibitor: time trends in baseline characteristics, treatment retention and response.

OBJECTIVES: To investigate time trends in baseline characteristics and retention, remission and response rates in bio-naïve axial spondyloarthritis (axSpA) and psoriatic arthritis (PsA) patients initiating TNF inhibitor (TNFi) treatment. METHODS: Prospectively collected data on bio-naïve axSpA and PsA patients from routine care in 15 European countries were pooled. Three cohorts were defined according to year of TNFi initiation: A (1999-2008), B (2009-2014) and C (2015-2018). Retention, remission and response rates were assessed at 6, 12 and 24 months. RESULTS: In total, 27 149 axSpA and 17 446 PsA patients were included. Cohort A patients had longer disease duration compared with B and C. In axSpA, cohort A had the largest proportion of male and HLA-B27 positive patients. In PsA, baseline disease activity was highest in cohort A. Retention rates in axSpA/PsA were highest in cohort A and differed only slightly between B and C. For all cohorts, disease activity decreased markedly from 0 to 6 months. In axSpA, disease activity at 24 months was highest in cohort A, where also remission and response rates were lowest. In PsA, remission rates at 6 and 12 months tended to be lowest in cohort A. Response rates were at all time points comparable across cohorts, and less between-cohort disease activity differences were seen at 24 months. CONCLUSION: Our findings indicate that over the past decades, clinicians have implemented more aggressive treatment strategies in spondyloarthritis. This was illustrated by shorter disease duration at treatment initiation, decreased retention rates and higher remission rates during recent years.

Maintaining musculoskeletal health using a behavioural therapy approach: a population-based randomised controlled trial (the MAmMOTH Study).

OBJECTIVE: Cognitive-behavioural therapy (CBT) has been shown to be effective in the management of chronic widespread pain (CWP); we now test whether it can prevent onset among adults at high risk. METHODS: A population-based randomised controlled prevention trial, with recruitment through UK general practices. A mailed screening questionnaire identified adults at high risk of CWP. Participants received either usual care (UC) or a short course of telephone CBT (tCBT). The primary outcome was CWP onset at 12 months assessed by mailed questionnaire. There were seven secondary outcomes including quality of life (EuroQol Questionnaire-five dimensions-five levels/EQ-5D-5L) used as part of a health economic assessment. RESULTS: 996 participants were randomised and included in the intention-to-treat analysis of which 825 provided primary outcome data. The median age of participants was 59 years; 59% were women. At 12 months there was no difference in the onset of CWP (tCBT: 18.0% vs UC: 17.5%; OR 1.05; 95% CI 0.75 to 1.48). Participants who received tCBT were more likely to report better quality of life (EQ-5D-5L utility score mean difference 0.024 (95% CI 0.009 to 0.040)); and had 0.023 (95% CI 0.007 to 0.039) more quality-adjusted life-years at an additional cost of £42.30 (95% CI -£451.19 to £597.90), yielding an incremental cost-effectiveness ratio of £1828. Most secondary outcomes showed significant benefit for the intervention. CONCLUSIONS: A short course of tCBT did not prevent onset of CWP in adults at high risk, but improved quality of life and was cost-effective. A low-cost, short-duration intervention benefits persons at risk of CWP. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT02668003).

Effectiveness and treatment retention of TNF inhibitors when used as monotherapy versus comedication with csDMARDs in 15 332 patients with psoriatic arthritis. Data from the EuroSpA collaboration.

BACKGROUND: Comedication with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) during treatment with tumour necrosis factor inhibitors (TNFi) is extensively used in psoriatic arthritis (PsA), although the additive benefit remains unclear. We aimed to compare treatment outcomes in patients with PsA treated with TNFi and csDMARD comedication versus TNFi monotherapy. METHODS: Patients with PsA from 13 European countries who initiated a first TNFi in 2006-2017 were included. Country-specific comparisons of 1 year TNFi retention were performed by csDMARD comedication status, together with HRs for TNFi discontinuation (comedication vs monotherapy), adjusted for age, sex, calendar year, disease duration and Disease Activity Score with 28 joints (DAS28). Adjusted ORs of clinical remission (based on DAS28) at 12 months were calculated. Between-country heterogeneity was assessed using random-effect meta-analyses, combined results were presented when heterogeneity was not significant. Secondary analyses stratified according to TNFi subtype (adalimumab/infliximab/etanercept) and restricted to methotrexate as comedication were performed. RESULTS: In total, 15 332 patients were included (62% comedication, 38% monotherapy). TNFi retention varied across countries, with significant heterogeneity precluding a combined estimate. Comedication was associated with better remission rates, pooled OR 1.25 (1.12-1.41). Methotrexate comedication was associated with improved remission for adalimumab (OR 1.45 (1.23-1.72)) and infliximab (OR 1.55 (1.21-1.98)) and improved retention for infliximab. No effect of comedication was demonstrated for etanercept. CONCLUSION: This large observational study suggests that, as used in clinical practice, csDMARD and TNFi comedication are associated with improved remission rates, and specifically, comedication with methotrexate increases remission rates for both adalimumab and infliximab.

Polygenic Risk Scores have high diagnostic capacity in ankylosing spondylitis.

OBJECTIVE: We sought to test the hypothesis that Polygenic Risk Scores (PRSs) have strong capacity to discriminate cases of ankylosing spondylitis (AS) from healthy controls and individuals in the community with chronic back pain. METHODS: PRSs were developed and validated in individuals of European and East Asian ethnicity, using data from genome-wide association studies in 15 585 AS cases and 20 452 controls. The discriminatory values of PRSs in these populations were compared with other widely used diagnostic tests, including C-reactive protein (CRP), HLA-B27 and sacroiliac MRI. RESULTS: In people of European descent, PRS had high discriminatory capacity with area under the curve (AUC) in receiver operator characteristic analysis of 0.924. This was significantly better than for HLA-B27 testing alone (AUC=0.869), MRI (AUC=0.885) or C-reactive protein (AUC=0.700). PRS developed and validated in individuals of East Asian descent performed similarly (AUC=0.948). Assuming a prior probability of AS of 10% such as in patients with chronic back pain under 45 years of age, compared with HLA-B27 testing alone, PRS provides higher positive values for 35% of patients and negative predictive values for 67.5% of patients. For PRS, in people of European descent, the maximum positive predictive value was 78.2% and negative predictive value was 100%, whereas for HLA-B27, these values were 51.9% and 97.9%, respectively. CONCLUSIONS: PRS have higher discriminatory capacity for AS than CRP, sacroiliac MRI or HLA-B27 status alone. For optimal performance, PRS should be developed for use in the specific ethnic groups to which they are to be applied.

The changing states of fibromyalgia in patients with axial spondyloarthritis: results from the British Society of Rheumatology Biologics Register for Ankylosing Spondylitis.

OBJECTIVES: To identify factors associated with FM development and recovery in patients with axial SpA (axSpA). METHODS: The British Society of Rheumatology Biologics Register for Ankylosing Spondylitis (BSRBR-AS) recruited patients with axSpA from 83 centres in a prospective study. FM was diagnosed using the self-reported Fibromyalgia Survey Diagnostic Criteria from 2015. Measures of axSpA disease activity and clinical findings were recorded at regular intervals. We identified predictors for FM development and recovery between yearly visits using uni- and multivariable logistic regression models. RESULTS: A total of 801 participants, 247 (30.8%) female, had two or more visits and were eligible for inclusion. A total of 686 participants did not have FM at baseline, of whom 45 had developed FM at follow-up, while 115 participants had FM at baseline, of whom 77 had recovered at follow-up. A high baseline BASDAI score [odds ratio (OR) 1.27 (95% CI 1.08, 1.49)] and Widespread Pain Index (WPI) [OR 1.14 (95% CI 1.02, 1.28)] were significantly associated with FM development in the final multivariable model. A low baseline BASFI score [OR 0.68 (95% CI 0.53, 0.86)] and WPI [OR 0.84 (95% CI 0.720, 0.97)] and starting a TNF inhibitor [OR 3.86 (95% CI 1.54, 9.71)] were significantly associated with FM recovery. CONCLUSION: High levels of disease activity and the presence of widespread pain is associated with the development of FM in patients with axSpA, while low levels of the same variables and starting a TNF inhibitor are associated with recovery from FM. The presence of comorbid FM should be considered in patients with persistent high axSpA disease activity and widespread pain.

Similar biologic drug response regardless of radiographic status in axial spondyloarthritis: data from the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis registry.

OBJECTIVE: To describe the baseline characteristics, biologic DMARD (bDMARD) response and drug survival of axial SpA (axSpA) patients in the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis (BSRBR-AS) according to radiographic status. METHODS: The BSRBR-AS is a national prospective cohort including axSpA participants classified according to the Assessment of SpondyloArthritis international Society criteria. In this analysis, baseline data of patients starting bDMARDs were compared. Ankylosing Spondylitis Disease Activity Scores (ASDASs) for low disease status, clinically important improvement (CII) and major improvement (MI) at 1 year were used to assess treatment response. Cox proportional hazards analysis was performed after adjusting for clinically relevant confounders. RESULTS: A total of 1145 axSpA patients were included. Higher male prevalence, older age and longer disease duration were seen in the radiographic axSpA (r-axSpA) subgroup. Based on a complete case analysis (290 patients), two-thirds of patients achieved an ASDAS low disease state at 1 year regardless of radiographic status [non-radiographic axSpA (nr-axSpA) 64.2% vs r-axSpA 66.1]. No statistically significant differences were seen between the subgroups in attaining ASDAS CII (nr-axSpA 50.7% vs r-axSpA 44.7%) or MI (nr-axSpA 20% vs r-axSpA 18.7%). Drug survival probability curves were similar for both subgroups and the hazard ratio for nr-axSpA/axSpA was 0.94 (95% CI 0.69, 1.28) when adjusted for sex, age, baseline ASDAS with CRP, smoking status, disease duration, HLA-B27 and prescribed biologic. CONCLUSIONS: Although there appeared to be some differences in the baseline characteristics when exploring this cohort according to radiographic status, which are likely related to the natural history of the disease, the level of biologic response and drug survival was comparable between nr-axSpA and r-axSpA.

Depression and anxiety symptoms at TNF inhibitor initiation are associated with impaired treatment response in axial spondyloarthritis.

OBJECTIVES: Depression and anxiety are associated with more severe disease in cross-sectional studies of axial spondyloarthritis (axSpA). We examined the association between baseline symptoms of depression or anxiety and response to TNF inhibitors (TNFi) in axSpA. METHODS: Biologic naïve participants from a national axSpA register completed the Hospital Anxiety and Depression Scale (HADS) before initiating TNFi. Symptoms of anxiety and depression were each categorized as moderate-severe (≥11), mild (8-10) and 'none' (≤7), and compared against change in disease indices [BASDAI and AS Disease Activity Score (ASDAS)] over time and time to treatment discontinuation using marginal structural models. Inverse-probability weights balanced baseline age, gender, BMI, deprivation, education and baseline values of respective disease indices. RESULTS: Of the 742 participants (67% male, mean age 45 years), 176 (24%) had moderate-severe and 26% mild depression; 295 (40%) had moderate-severe and 23% mild anxiety. Baseline disease activity was higher in higher HADS symptom categories for both depression and anxiety. Participants with moderate-severe depression had significantly poorer response compared with those with 'none' throughout follow-up. At 6 months, the difference was approximately 2.2 BASDAI and 0.8 ASDAS units after balancing their baseline values. Equivalent comparisons for anxiety were 1.7 BASDAI and 0.7 ASDAS units. Treatment discontinuation was 1.59-fold higher (hazard ratio 95% CI: 1.12, 2.26) in participants with moderate-severe anxiety compared with 'none'. CONCLUSIONS: Symptoms of depression and anxiety at TNFi initiation are associated with poorer treatment outcomes. Targeted interventions to optimize mental health have potential to substantially improve treatment response and persistence.

Comorbidity and response to TNF inhibitors in axial spondyloarthritis: longitudinal analysis of the BSRBR-AS.

OBJECTIVE: Comorbidities influence disease assessment in axial spondyloarthritis (axSpA), but their association with response to TNF inhibitors (TNFi) is unclear. We examined associations between comorbidity history at TNFi initiation and: (i) change in disease indices over time; (ii) binary response definitions; and (iii) time to treatment discontinuation. METHODS: We studied participants starting their first TNFi from a national axSpA register. Comorbidity categories were created from 14 physician-diagnosed conditions and compared against: change in disease indices over time using linear mixed effects models; BASDAI50/2 (50% or 2-unit reduction) and BASDAI < 4 at 6 months using logistic models; and time to treatment discontinuation using Cox models. Models were adjusted for age, gender, BMI, deprivation and education. RESULTS: In total, 994 were eligible for analysis (68% male, mean age 45 years); 21% had one comorbidity and 11% had ≥2. Baseline disease severity was higher in those with comorbidities across all indices, but absolute improvement over time was comparable for BASDAI and spinal pain. Participants with ≥2 comorbidities had smaller absolute improvement in BASFI and quality of life. This group also had numerically reduced odds of achieving BASDAI50/2 [odds ratio (OR) 0.81; 95% CI: 0.45, 1.45] and BASDAI < 4 (OR 0.57; 95% CI: 0.32, 1.04). Treatment discontinuation was increased in those with two comorbidities [hazard ratio (HR) 1.32; 95% CI: 0.88, 2.00] and ≥3 comorbidities (HR 2.18; 95% CI: 1.20, 3.93) compared with none. CONCLUSIONS: Participants with multiple comorbidities had poorer treatment outcomes, particularly increased treatment discontinuation and poorer improvements in function and quality of life. These results inform clinicians and educate patients about response to the first TNFi given comorbidity burden.

Association between comorbidities and disease activity in axial spondyloarthritis: results from the BSRBR-AS.

OBJECTIVE: Whether comorbidities influence disease activity assessment in axial SpA (axSpA) is unclear. Comorbidities inflate DAS28 in rheumatoid arthritis through the patient global score. We examined whether axSpA disease activity measures are differentially affected, and whether comorbidities inflate the AS disease activity score (ASDAS) through the patient global component. METHODS: We used baseline data from the British Society for Rheumatology Biologics Register for AS, including 14 physician diagnosed comorbidities. Linear models were used to compare disease activity (BASDAI, spinal pain, ASDAS) and ESR/CRP according to comorbidity count, adjusted for age, gender, BMI, smoking, socioeconomic status, and education. The same models were used to examine whether the patient global score was associated with comorbidities, additionally adjusting for other ASDAS components. RESULTS: The number of participants eligible for analysis was 2043 (67% male, mean age 49 years); 44% had at least one comorbidity. Each additional comorbidity was associated with higher BASDAI by 0.40 units (95% CI: 0.27, 0.52) and spinal pain by 0.53 (95% CI: 0.37, 0.68). Effect size for ASDAS (0.09 units; 95% CI: 0.03, 0.15) was not clinically significant. ESR and CRP were not associated with comorbidity count. Depression, heart failure and peptic ulcer were consistently associated with higher disease activity measures, but not CRP/ESR. Patient global was associated with comorbidity count, but not independently of other ASDAS components (P = 0.75). CONCLUSION: Comorbidities were associated with higher patient reported disease activity in axSpA. Clinicians should be mindful of the potential impact of comorbidities on patient reported outcome measures and consider additionally collecting ASDAS when comorbidities are present.

The effect of COVID-19 public health restrictions on the health of people with musculoskeletal conditions and symptoms: the CONTAIN study.

OBJECTIVE: To quantify the change in quality of life, disease-specific indicators, health and lifestyle before and during the COVID-19 pandemic among people with musculoskeletal diagnoses and symptoms. METHODS: We undertook an additional follow-up of two existing UK registers involving people with axial spondyloarthritis (axSpA) or psoriatic arthritis (PsA) and participants in a trial in the UK who had regional pain and were identified at high risk of developing chronic widespread pain. Participants completed the study questionnaire between July and December 2020, throughout which time there were public health restrictions in place. RESULTS: The number of people taking part in the study was 1054 (596 axSpA, 162 PsA, 296 regional pain). In comparison with their previous (pre-pandemic) assessment, there was an age-adjusted significant, small decrease in quality of life measured by EQ-5D [-0.020 (95% CI -0.030, -0.009)] overall and across all population groups examined. This was primarily related to poorer mental health and pain. There was a small increase in fibromyalgia symptoms, but a small decrease in sleep problems. There was a small deterioration in axSpA disease activity, and disease-specific quality of life and anxiety in PsA participants. Predictors of poor quality of life were similar pre- and during the pandemic. The effect of lockdown on activity differed according to age, gender and deprivation. CONCLUSION: Important lessons include focusing on addressing anxiety and providing enhanced support for self-management in the absence of normal health care being available, and awareness that all population groups are likely to be affected.

Real-world evidence of TNF inhibition in axial spondyloarthritis: can we generalise the results from clinical trials?

Management guidelines assume that results from clinical trials can be generalised, although seldom is data available to test this assumption. We aimed to determine the proportion of patients commencing tumour necrosis factor inhibition (TNFi) who would have been eligible for relevant clinical trials, and whether treatment response differs between these groups and the trials themselves. The British Society for Rheumatology Biologics Register for Ankylosing Spondylitis (BSRBR-AS) recruited a real-world cohort of TNFi-naïve spondyloarthritis patients with data collection from clinical records and patient questionnaires. Participant characteristics were extracted from trials identified from a recent Health Technology Assessment of TNFi for ankylosing spondylitis/non-radiographic axial spondyloarthritis. Descriptive statistics were used to determine the differences, including treatment response, between BSRBR-AS participants who would/would not have been eligible for the clinical trials and with trial participants. Among 2420 BSRBR-AS participants, those commencing TNFi (34%) had shorter symptom duration (15 vs 22 years) but more active disease (Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) 6.4 vs 4.0; Bath Ankylosing Spondylitis Disease Functional Index (BASFI) 6.2 vs 3.8). Of those commencing TNFi, 41% met eligibility criteria for ≥1 of fourteen relevant trials; they reported higher disease activity (BASDAI 6.9 vs 6.1) and poorer function (BASFI 6.6 vs 6.0). 61.7% of trial participants reported a positive treatment response, vs 51.3% of BSRBR-AS patients (difference: 10.4%; 95% CI 4.4% to 16.5%). Potential eligibility for trials did not influence treatment response (difference 2.0%; -9.4% to 13.4%). Fewer patients in the real world respond to TNFi than is reported in the trial literature. This has important implications for the generalisability of trial results, and the cost-effectiveness of TNFi agents.

Determining factors related to poor quality of life in patients with axial spondyloarthritis: results from the British Society for Rheumatology Biologics Register (BSRBR-AS).

OBJECTIVE: To determine modifiable factors associated with poor quality of life (QoL) in patients with axial spondyloarthritis (axSpA). METHODS: Analysis of data from the British Society for Rheumatology Biologics Register in Ankylosing Spondylitis (BSRBR-AS) and validation of a previous model using data from 1810 patients with axSpA recruited during 2012-2017. Data collected included clinical and patient-reported measures. QoL was assessed using the Ankylosing Spondylitis Quality of Life (ASQoL) measure. Linear regression models predicting ASQoL scores were used first to validate a previous model from a national study, to extend this with additional information available in BSRBR-AS and finally to identify a 'de novo' model from BSRBR-AS of which factors impact on poor QoL. RESULTS: Four out of five factors included in a previous model of poor QoL in patients with axSpA were confirmed: Bath Ankylosing Spondylitis Disease Activity Index and Bath Ankylosing Spondylitis Functional Index, fatigue and widespread pain, although the performance of the model was improved by the addition of measures of mood and sleep disturbance. In a de novo model in BSRBR-AS, there were six factors (other than disease activity and function) that predicted ASQoL: depression (ß=0.16), sleep disturbance (ß=0.08), activity impairment (ß=0.04), fibromyalgia (Symptom Severity Scale (ß=0.24) and Widespread Pain Index (ß=0.10)) and tobacco smoking (ß=0.66). CONCLUSION: This study confirms that poor QoL in patients with axSpA, in addition to high disease activity and poor function, is independently influenced by sleep disturbance, mood and widespread pain. These additional factors are not considered targets for treatment in current European League Against Rheumatism (EULAR) guidelines for managing the condition.

Predicting response to anti-TNFα therapy among patients with axial spondyloarthritis (axSpA): results from BSRBR-AS.

OBJECTIVES: While many axSpA patients, eligible to receive anti-TNFα therapy, derive benefit when prescribed them, some patients do not. The current study aims to identify modifiable targets to improve outcome as well as non-modifiable targets that identify groups less likely to derive benefit. METHODS: The BSRBR-AS is a prospective cohort study of axSpA patients who, at recruitment, were naïve to biologic therapy. Those in the 'biologic' sub-cohort commenced their first anti-TNFα therapy at recruitment or during follow-up. Prior to commencement, information was collected on socio-economic, clinical and patient-reported factors. Outcome was assessed according to ASAS20, ASAS40, ASDAS reduction and achieving a moderate/inactive ASDAS disease state. RESULTS: 335 participants commenced their first anti-TNFα therapy and were followed up at a median of 14 (inter-quartile range 12-17) weeks. Response varied between 33% and 52% according to criteria used. Adverse socio-economic factors, fewer years in education predicted lower likelihood of response across outcome measures as did not working full-time. Co-morbidities and poor mental health were clinical and patient-reported factors, respectively, associated with lack of response. The models, particularly those using ASDAS, were good at predicting those who did not respond (negative predictive value (NPV) 77%). CONCLUSION: Some factors predicting non-response (such as mental health) are modifiable but many (such as social/economic factors) are not modifiable in clinic. They do, however, identify patients who are unlikely to benefit from biologic therapy alone. Priority should focus on how these patients receive the benefits that many derive from such therapies.

Quantifying and predicting the effect of anti-TNF therapy on axSpA-related fatigue: results from the BSRBR-AS registry and meta-analysis.

OBJECTIVES: Effective management of axial spondyloarthritis (axSpA)-related fatigue is a major unmet clinical need. Anti-TNF therapy may reduce fatigue levels, although any effect has yet to be definitively quantified and predictors of any such improvements are unknown. METHODS: The British Society of Rheumatology Register in Axial Spondyloarthritis (BSRBR-AS) prospectively recruited axSpA patients across the UK. Changes in fatigue levels (measured using the Chalder Fatigue Scale) >1 year were compared between those starting anti-TNF therapy at the time of recruitment and those not. Differences between treatment groups were adjusted using propensity score matching. Results were meta-analysed with the extant literature to calculate pooled estimates. Then, among those BSRBR-AS anti-TNF commencers with clinically relevant fatigue, baseline predictors of response were investigated. RESULTS: Of the 998 BSRBR-AS recruits with complete fatigue data, 310 were anti-TNF commencers. At 1-year follow-up, the former group reported a mean fatigue change of -2.6 (95% CI -4.1, -1.9) points while the latter reported a mean worsening of fatigue by 0.2 points. Following propensity score adjustment, those commencing anti-TNF therapy reduced fatigue by 3.0 points compared with those not. Of those with significant fatigue and commencing anti-TNF, poor sleep quality at baseline predicted fatigue improvement. In the meta-analysis, including 1109 subjects, treatment with anti-TNF therapy resulted in a significant improvement in fatigue [Standardized mean difference (SMD) = 0.36, 95% CI 0.15, 1.56]. CONCLUSION: Anti-TNF therapy results in a significant but modest reduction in fatigue amongst axSpA patients, with those reporting poor sleep quality most likely to report improvement. Effective management will likely require additional approaches.

Impact of discordance between patient's and evaluator's global assessment on treatment outcomes in 14 868 patients with spondyloarthritis.

OBJECTIVES: To assess the impact of 'patient's minus evaluator's global assessment of disease activity' (ΔPEG) at treatment initiation on retention and remission rates of TNF inhibitors (TNFi) in psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) patients across Europe. METHODS: Real-life data from PsA and axSpA patients starting their first TNFi from 11 countries in the European Spondyloarthritis Research Collaboration Network were pooled. Retention rates were compared by Kaplan-Meier analyses with log-rank test and by Cox regression, and remission rates by χ2 test and by logistic regression across quartiles of baseline ΔPEG, separately in female and male PsA and axSpA patients. RESULTS: We included 14 868 spondyloarthritis (5855 PsA, 9013 axSpA) patients. Baseline ΔPEG was negatively associated with 6/12/24-months' TNFi retention rates in female and male PsA and axSpA patients (P <0.001), with 6/12/24-months' BASDAI < 2 (P ≤0.002) and ASDAS < 1.3 (P ≤0.005) in axSpA patients, and with DAS28CRP(4)<2.6 (P ≤0.04) and DAPSA28 ≤ 4 (P ≤0.01), but not DAS28CRP(3)<2.6 (P ≥0.13) in PsA patients, with few exceptions on remission rates. Retention and remission rates were overall lower in female than male patients. CONCLUSION: High baseline patient's compared with evaluator's global assessment was associated with lower 6/12/24-months' remission as well as retention rates of first TNFi in both PsA and axSpA patients. These results highlight the importance of discordance between patient's and evaluator's perspective on disease outcomes.

The prevalence of fibromyalgia in axial spondyloarthritis.

Comorbid fibromyalgia, in axial spondyloarthritis (axSpA) has been shown to influence disease activity and function, and quality of life. Although several papers exist, there is no comprehensive and robust systematic review to determine the prevalence of fibromyalgia in this patient group. Thus, the aim of the current study was to provide a definitive estimate of prevalence of fibromyalgia in axSpA, and in axSpA sub-classifications. A systematic literature search was conducted in Ovid MEDLINE, EMBASE, Evidence Based Medicine (EBM), and Cochrane Library, updated to April 2020, combining keywords and relevant MeSH headings, to identify papers reporting the prevalence of fibromyalgia in axSpA, or data from which this could be computed. This was then combined in a meta-analysis with data from the Scotland Registry for Ankylosing Spondylitis (SIRAS), a national axSpA register in Scotland. Data was pooled using random or fixed effects models where heterogeneity was greater or lesser than 75%. From 3401 manuscripts initially identified, 15 papers were included in the final review, plus SIRAS, giving data from 16 separate sources. The prevalence of fibromyalgia, among a total of 5214 patients, was 16.4% (95% CI 12.3-20.5%). Prevalence varied with axSpA sub-classification: ankylosing spondylitis: 13.8% (9.1-18.6%); MRI positive non-radiographic axSpA 20.3% (6.5-34.1%); and 'clinical' disease: 11.1% (6.0-16.2%). Overall, around 1 in 6 patients with axSpA also meet criteria for fibromyalgia. While estimates from individual studies vary, comorbid fibromyalgia represents a considerable burden across all sub-classifications of axSpA. This emphasises that focusing management solely on inflammatory disease in this patient group is unlikely to yield optimal improvements in quality of life.

Associations between smoking and extra-axial manifestations and disease severity in axial spondyloarthritis: results from the BSR Biologics Register for Ankylosing Spondylitis (BSRBR-AS).

OBJECTIVE: The effects of smoking on disease manifestations in axial SpA are inadequately described. Utilizing a large and well-characterized cohort, we investigated the association between smoking and extra-axial manifestations, and smoking and disease severity measures. METHODS: Baseline data from the British Society for Rheumatology Biologics Register for Ankylosing Spondylitis were explored. Our analyses focused on extra-axial manifestations and other disease severity measures, including scales for fatigue, sleep, anxiety and depression. Logistic and linear models were used to quantify associations between disease characteristics according to smoking status (current/ex/never) and quantity (heavy/light), adjusting for age, gender, BMI, education, deprivation, comorbidities, symptom duration and alcohol status. RESULTS: A total of 2031 participants were eligible for the current analysis (68% male, mean age 49 years). Of these, 24% were current and 32% ex-smokers. When compared with non-smokers, current smokers had lower odds of uveitis [OR 0.7, 95% CI 0.5-0.9] and higher odds of psoriasis (ORadj 1.6, 95% CI 1.1-2.3). Ex- and current smokers had incrementally more severe disease than never smokers, with higher BASDAI (ß = 0.3, 95% CI 0.1-0.6; ß = 0.9, 95% CI 0.6-1.2) and BASFI (ß = 0.5, 95% CI 0.2-0.8; ß = 1.3, 95% CI 1.0-1.6); similar associations were observed for fatigue, sleep, anxiety and depression. CONCLUSION: In this large cross-sectional study, we observed that smoking is independently associated with an adverse disease profile in axial SpA, including worse fatigue, sleep, anxiety and depression, and higher odds of psoriasis. The paradoxical association between current smoking and reduced odds of uveitis is interesting and warrants further investigation.

Cost-utility of maintained physical activity and physiotherapy in the management of distal arm pain: an economic evaluation of data from a randomized controlled trial.

BACKGROUND: Arm pain is common, costly to health services and society. Physiotherapy referral is standard management, and while awaiting treatment, advice is often given to rest, but the evidence base is weak. OBJECTIVE: To assess the cost-effectiveness of advice to remain active (AA) versus advice to rest (AR); and immediate physiotherapy (IP) versus usual care (waiting list) physiotherapy (UCP). METHODS: Twenty-six-week within-trial economic evaluation (538 participants aged ≥18 years randomized to usual care, i.e. AA (n = 178), AR (n = 182) or IP (n = 178). Regression analysis estimated differences in mean costs and Quality-Adjusted Life Years (QALYs). Incremental cost-effectiveness ratios (ICERs) and cost-effectiveness acceptability curves were generated. Primary analysis comprised the 193 patients with complete resource use (UK NHS perspective) and EQ-5D data. Sensitivity analysis investigated uncertainty. RESULTS: Baseline-adjusted cost differences were £88 [95% confidence interval (CI): -14, 201) AA versus AR; -£14 (95% CI: -87, 66) IP versus UCP. Baseline-adjusted QALY differences were 0.0095 (95% CI: -0.0140, 0.0344) AA versus AR; 0.0143 (95% CI: -0.0077, 0.0354) IP versus UCP. There was a 71 and 89% probability that AA (versus AR) and IP (versus UCP) were the most cost-effective option using a threshold of £20,000 per additional QALY.  The results were robust in the sensitivity analysis. CONCLUSION: The difference in mean costs and mean QALYs between the competing strategies was small and not statistically significant. However, decision-makers may judge that IP was not shown to be any more effective than delayed treatment, and was no more costly than delayed physiotherapy. AA is preferable to one that encourages AR, as it is more effective and more likely to be cost-effective than AR.