Diagnostic delay is associated with uveitis and inflammatory bowel disease in AS: a study of extra-musculoskeletal manifestations in SpA.

OBJECTIVES: To examine the prevalence of extra-musculoskeletal manifestations (EMM) and the association between diagnostic delay and their incidence in AS and PsA. METHODS: This was a retrospective, cohort study comprising two single centre cohorts in Europe and one multicentre cohort in Latin America (RESPONDIA). Crude prevalence of EMMs (uveitis, IBD and psoriasis) was calculated across geographic area and adjusted by direct standardization. Cox proportional hazard analysis was performed to assess the association between diagnostic delay and EMM incidence. RESULTS: Of 3553 patients, 2097 had AS and 1456 had PsA. The overall prevalence of uveitis was 22.9% (95% CI: 21.1, 24.8) in AS and 3.8% (95% CI: 2.9, 5.0) in PsA; 8.1% (95% CI: 7.0, 9.4) and 2.1% (1.3, 2.9), respectively, for IBD; and 11.0% (95% CI: 9.7, 12.4) and 94.6% (93.0, 95.9), respectively, for psoriasis. The EMM often presented before the arthritis (uveitis 45.1% and 33.3%, and IBD 37.4% and 70%, in AS and PsA, respectively). In the multivariable model, longer diagnostic delay (≥5 years) associated with more uveitis (hazard ratio [HR] 4.01; 95% CI: 3.23, 4.07) and IBD events (HR 1.85; 95% CI: 1.28, 2.67) in AS. Diagnostic delay was not significantly associated with uveitis (HR 1.57; 95% CI: 0.69, 3.59) or IBD events (HR 1.59; 95% CI: 0.39, 6.37) in PsA. CONCLUSION: EMMs are more prevalent in AS than PsA and often present before the onset of the articular disease. A longer diagnostic delay is associated with the 'de novo' appearance of uveitis and IBD in AS, highlighting the need to enhance diagnostic strategies to shorten the time from first symptom to diagnosis in SpA.

The COVID-19 epidemic curve and vaccine acceptance among patients with rheumatic diseases: an ecological study.

The attitudes toward emerging COVID-19 vaccines have been of great interest worldwide, especially among vulnerable populations such as patients with rheumatic and musculoskeletal diseases (RMDs). The aim of this study was to analyze the relationship between the nationwide number of COVID-19 cases and deaths, and vaccine acceptance or hesitancy of patients with RMDs from four patient care centers in Mexico. Furthermore, we explored differences in acceptance according to specific diagnoses: rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). This ecological study was a secondary analysis of a cross-sectional study using a validated questionnaire to measure vaccine acceptance. We generated a global Likert scale to evaluate overall attitudes toward the COVID-19 vaccine. We analyzed data from 1336 patients from March to September 2021: 85.13% (1169) were women, with a mean age of 47.87 (SD 14.14) years. The most frequent diagnoses were RA (42.85%, 559) and SLE (27.08%, 393). 635(47.52%) patients were unvaccinated, 253(18.93%) had one dose and 478(35.77%) had two doses. Of all participating patients, 94% were accepting toward the COVID-19 vaccine. Vaccine acceptance remained consistently high throughout the study. However, differences in vaccine acceptance are identified when comparing diagnoses. The peak of the national epidemic curve coincided with an increase in hesitancy among patients with RA. Contrastingly, patients with SLE became more accepting as the epidemic curve peaked. Mexican patients show high acceptance of the COVID-19 vaccine, influenced in part by a patient's specific diagnosis. Furthermore, vaccine acceptance increased mirroring the curve of COVID-19 cases and deaths in the country. This should be taken into consideration when updating recommendations for clinical practice.

Inflammasome genes polymorphisms and susceptibility to gout. Is there a link?

Background: The inflammatory response in gout disease is induced by the activation of NLR family pyrin domain-containing 3 (NLPR3) signaling pathway mediated by IL-1ß release. Objective: The objective of the study was to determine the association between single nucleotide polymorphisms (SNPs) within NLRP3 inflammasome genes and gout susceptibility. Methods: Mexican patients with gout from the National Rehabilitation Institute and General Hospital of Mexico were enrolled. A healthy control group was also included. We analyzed the frequency and allelic distribution of eight SNPs from seven different genes within the NLRP3 inflammasome signaling pathway: TLR4 rs2149356, CD14 rs2569190, NLRP3 rs3806268, NLRP3 rs10754558, CARD8 rs2043211, IL-1ß rs1143623, P2RX7 rs3751142, and PPARGC1B rs45520937 SNPs. Results: We found that the SNP rs45520937 of PPARGC1B was associated with the risk of developing gout when it was analyzed using the dominant model (Odds ratio [OR] = 2.30; 95% confidence interval [CI]: 1.09-4.86; p = 0.030), and it is proposed that the adaptor molecule CD14 rs2569190 polymorphism could be associated with a lower risk of gout under an additive model (OR= 0.41;95% CI: 0.16-1.05; p = 0.064). No significant associations were identified for the remaining SNPs. Conclusion: Our findings suggest that the PPARGC1B rs45520937 SNP is associated with gout susceptibility.

Taxonomic variations in the gut microbiome of gout patients with and without tophi might have a functional impact on urate metabolism.

OBJECTIVE: To evaluate the taxonomic composition of the gut microbiome in gout patients with and without tophi formation, and predict bacterial functions that might have an impact on urate metabolism. METHODS: Hypervariable V3-V4 regions of the bacterial 16S rRNA gene from fecal samples of gout patients with and without tophi (n = 33 and n = 25, respectively) were sequenced and compared to fecal samples from 53 healthy controls. We explored predictive functional profiles using bioinformatics in order to identify differences in taxonomy and metabolic pathways. RESULTS: We identified a microbiome characterized by the lowest richness and a higher abundance of Phascolarctobacterium, Bacteroides, Akkermansia, and Ruminococcus_gnavus_group genera in patients with gout without tophi when compared to controls. The Proteobacteria phylum and the Escherichia-Shigella genus were more abundant in patients with tophaceous gout than in controls. Fold change analysis detected nine genera enriched in healthy controls compared to gout groups (Bifidobacterium, Butyricicoccus, Oscillobacter, Ruminococcaceae_UCG_010, Lachnospiraceae_ND2007_group, Haemophilus, Ruminococcus_1, Clostridium_sensu_stricto_1, and Ruminococcaceae_UGC_013). We found that the core microbiota of both gout groups shared Bacteroides caccae, Bacteroides stercoris ATCC 43183, and Bacteroides coprocola DSM 17136. These bacteria might perform functions linked to one-carbon metabolism, nucleotide binding, amino acid biosynthesis, and purine biosynthesis. Finally, we observed differences in key bacterial enzymes involved in urate synthesis, degradation, and elimination. CONCLUSION: Our findings revealed that taxonomic variations in the gut microbiome of gout patients with and without tophi might have a functional impact on urate metabolism.

Which factors predict discordance between a patient and physician on a gout flare?

OBJECTIVE: To investigate the factors associated with discordance between patient and physician on the presence of a gout flare. METHODS: Patients' self-reports of current gout flares were assessed with the question, 'Are you having a gout flare today?' which was then compared with a concurrent, blinded, physician's assessment. Based on agreement or disagreement with physicians on the presence of a gout flare, flares were divided into concordant and discordant groups, respectively. Within the discordant group, two subgroups-patient-reported flare but the physician disagreed and physician-reported flare but the patient disagreed-were identified. The factors associated with discordance were analysed with multivariable logistic regression analysis. RESULTS: Of 268 gout flares, 81 (30.2%) flares were discordant, with either patient or physician disagreeing on the presence of a flare. Of the discordant flares, in 57 (70.4%) the patient reported a flare but the physician disagreed. In multivariable logistic regression analysis adjusted for demographics, disagreement among patients and physicians on the presence of a gout flare was associated with lower pain scores at rest [odds ratio (OR) for each point increase on 0-10 point pain scale 0.81 (95% Wald CI 0.73, 0.90), P < 0.0001] and less presence of joint swelling [OR 0.24 (95% CI 0.10, 0.61), P = 0.003] or joint warmth [OR 0.39 (95% CI 0.20, 0.75), P = 0.005]. CONCLUSION: Although patients and physicians generally agree about the presence of gout flare, discordance may occur in the setting of low pain scores and in the absence of swollen or warm joints.

How to calculate the ASDAS based on C-reactive protein without individual questions from the BASDAI: the BASDAI-based ASDAS formula.

OBJECTIVES: To develop a new equation to calculate the Ankylosing Spondylitis Disease Activity Score based on CRP (ASDAS-CRP) using only the BASDAI total score and CRP. METHODS: Axial SpA (axSpA) patients from the Cordoba Spondyloarthritis Registry cohort were recruited as a derivation cohort, while a retrospective sample from the Spanish Rheumatology Society National Registry of Spondyloarthropathies and Ibero American Spondyloarhtritis Registry registers was used as a validation cohort. We built a new equation based only on the BASDAI and CRP, defining a new formula: the BASDAI-based ASDAS (BASDAS). Linear regression analysis was used to determine the coefficients of the equation in the derivation cohort and it was subsequently validated in the validation cohort. RESULTS: A total of 52 axSpA patients in the derivation cohort and 3359 patients in the validation cohort were included. In the derivation cohort, the mean BASDAS [2.24 (s.d. 0.90)] was very similar to the ASDAS-CRP [2.23 (s.d. 0.95)], with a very strong correlation (r = 0.96, P < 0.001). In the validation cohort, the mean BASDAS was 3.31 (s.d. 1.37) and the ASDAS-CRP was 3.19 (s.d. 1.27), which also had a very strong correlation (r = 0.95, P < 0.001). Intraclass correlation coefficients were excellent in both cohorts (0.963 and 0.947, respectively). CONCLUSION: The BASDAS performs similarly to the ASDAS-CRP and can be calculated with only the BASDAI total score and CRP, allowing evaluation of disease activity in retrospective studies where the individual items of the BASDAI are not available.

Gout, Hyperuricaemia and Crystal-Associated Disease Network (G-CAN) consensus statement regarding labels and definitions of disease states of gout.

OBJECTIVE: There is a lack of standardisation in the terminology used to describe gout. The aim of this project was to develop a consensus statement describing the recommended nomenclature for disease states of gout. METHODS: A content analysis of gout-related articles from rheumatology and general internal medicine journals published over a 5-year period identified potential disease states and the labels commonly assigned to them. Based on these findings, experts in gout were invited to participate in a Delphi exercise and face-to-face consensus meeting to reach agreement on disease state labels and definitions. RESULTS: The content analysis identified 13 unique disease states and a total of 63 unique labels. The Delphi exercise (n=76 respondents) and face-to-face meeting (n=35 attendees) established consensus agreement for eight disease state labels and definitions. The agreed labels were as follows: 'asymptomatic hyperuricaemia', 'asymptomatic monosodium urate crystal deposition', 'asymptomatic hyperuricaemia with monosodium urate crystal deposition', 'gout', 'tophaceous gout', 'erosive gout', 'first gout flare' and 'recurrent gout flares'. There was consensus agreement that the label 'gout' should be restricted to current or prior clinically evident disease caused by monosodium urate crystal deposition (gout flare, chronic gouty arthritis or subcutaneous tophus). CONCLUSION: Consensus agreement has been established for the labels and definitions of eight gout disease states, including 'gout' itself. The Gout, Hyperuricaemia and Crystal-Associated Disease Network recommends the use of these labels when describing disease states of gout in research and clinical practice.

Evaluation of medical ethics competencies in rheumatology: local experience during national accreditation process.

INTRODUCTION: Rheumatologists are the primary healthcare professionals responsible for patients with rheumatic diseases and should acquire medical ethical competencies, such as the informed consent process (ICP). The objective clinical structured examination is a valuable tool for assessing clinical competencies. We report the performance of 90 rheumatologist trainees participating in a station designed to evaluate the ICP during the 2018 and 2019 national accreditations. METHODS: The station was validated and represented a medical encounter in which the rheumatologist informed a patient with systemic lupus erythematosus with clinically active nephritis about renal biopsy. A trained patient-actor and an evaluator were instructed to assess ICP skills (with a focus on kidney biopsy benefits, how the biopsy is done and potential complications) in obtaining formal informed consent, delivering bad news and overall communication with patients. The evaluator used a tailored checklist and form. RESULTS: Candidate performance varied with ICP content and was superior for potential benefit information (achieved by 98.9% of the candidates) but significantly reduced for potential complications (37.8%) and biopsy description (42.2%). Only 17.8% of the candidates mentioned the legal perspective of ICP. Death (as a potential complication) was omitted by the majority of the candidates (93.3%); after the patient-actor challenged candidates, only 57.1% of them gave a clear and positive answer. Evaluators frequently rated candidate communications skills as superior (≥80%), but ≥1 negative aspect was identified in 69% of the candidates. CONCLUSIONS: Ethical competencies are mandatory for professional rheumatologists. It seems necessary to include an ethics competency framework in the curriculum throughout the rheumatology residency.

Performance of classification criteria for gout in early and established disease.

OBJECTIVES: To compare the sensitivity and specificity of different classification criteria for gout in early and established disease. METHODS: This was a cross-sectional study of consecutive rheumatology clinic patients with joint swelling in which gout was defined by presence or absence of monosodium urate crystals as observed by a certified examiner at presentation. Early disease was defined as patient-reported onset of symptoms of 2 years or less. RESULTS: Data from 983 patients were collected and gout was present in 509 (52%). Early disease was present in 144 gout cases and 228 non-cases. Sensitivity across criteria was better in established disease (95.3% vs 84.1%, p<0.001) and specificity was better in early disease (79.9% vs 52.5%, p<0.001). The overall best performing clinical criteria were the Rome criteria with sensitivity/specificity in early and established disease of 60.3%/84.4% and 86.4%/63.6%. Criteria not requiring synovial fluid analysis had sensitivity and specificity of less than 80% in early and established disease. CONCLUSIONS: Existing classification criteria for gout have sensitivity of over 80% in early and established disease but currently available criteria that do not require synovial fluid analysis have inadequate specificity especially later in the disease. Classification criteria for gout with better specificity are required, although the findings should be cautiously applied to non-rheumatology clinic populations.

Peripheral neuropathy in patients with gout, beyond focal nerve compression: a cross-sectional study.

Neuropathies secondary to tophus compression in gout patients are well known; however, limited data exist on other types of peripheral neuropathies (PN). Our aim was to describe PN frequency, characteristics, distribution, patterns, and associated factors in gout patients through clinical evaluation, a PN questionnaire, and nerve conduction studies (NCS). This cross-sectional descriptive study included consecutive gout patients (ACR/EULAR 2015 criteria) from our clinic. All underwent evaluation by Rheumatology and Rehabilitation departments, with IRB approval. Based on NCS, patients were categorized as PN + (presence) or PN- (absence). PN + patients were further classified as local peripheral neuropathy (LPN) or generalized somatic peripheral neuropathy (GPN). We enrolled 162 patients, 98% male (72% tophaceous gout). Mean age (SD): 49.4 (12) years; mean BMI: 27.9 (6.0) kg/m2. Comorbidities included dyslipidemia (53%), hypertension (28%), and obesity (23.5%). Abnormal NCS: 65% (n = 106); 52% LPN, 48% GPN. PN + patients were older, had lower education, and severe tophaceous gout. GPN patients were older, had lower education, and higher DN4 scores compared to LPN or PN- groups (p = 0.05); other risk factors were not significant. Over half of gout patients experienced neuropathy, with 48% having multiplex mononeuropathy or polyneuropathy. This was associated with joint damage and functional impairment. Mechanisms and risk factors remain unclear. Early recognition and management are crucial for optimizing clinical outcomes and quality of life in these patients. Key Points Peripheral neuropathies in gout patients had been scarcely reported and studied. This paper report that: • PN in gout is more frequent and more diverse than previously reported. • Mononeuropathies are frequent, median but also ulnar, peroneal and tibial nerves could be injured. • Unexpected, generalized neuropathies (polyneuropathy and multiplex mononeuropathy) are frequent and associated to severe gout. • The direct role of hyperuricemia /or gout in peripheral nerves require further studies.

Long-term safety of pegloticase in chronic gout refractory to conventional treatment.

OBJECTIVE: To evaluate the long-term safety (up to 3 years) of treatment with pegloticase in patients with refractory chronic gout. METHODS: This open-label extension (OLE) study was conducted at 46 sites in the USA, Canada and Mexico. Patients completing either of two replicate randomised placebo-controlled 6-month trials received pegloticase 8 mg every 2 weeks (biweekly) or every 4 weeks (monthly). Safety was evaluated as the primary outcome, with special interest in gout flares and infusion-related reactions (IRs). Secondary outcomes included urate-lowering and clinical efficacy. RESULTS: Patients (n=149) received a mean±SD of 28±18 pegloticase infusions and were followed for a mean of 25±11 months. Gout flares and IRs were the most frequently reported adverse events; these were least common in patients with a sustained urate-lowering response to treatment and those receiving biweekly treatment. In 10 of the 11 patients with a serious IR, the event occurred when uric acid exceeded 6 mg/dl. Plasma and serum uric acid levels remained <6 mg/dl in most randomised controlled trial (RCT)-defined pegloticase responders throughout the OLE study and were accompanied by sustained and progressive improvements in tophus resolution and flare incidence. CONCLUSIONS: The safety profile of long-term pegloticase treatment was consistent with that observed during 6 months of RCT treatment; no new safety signals were identified. Improvements in clinical status, in the form of flare and tophus reduction initiated during RCT pegloticase treatment in patients maintaining goal range urate-lowering responses were sustained or advanced during up to 2.5 years of additional treatment.

An analysis of 372 patients with anterior uveitis in a large Ibero-American cohort of spondyloarthritis: the RESPONDIA Group.

OBJECTIVES: This study analysed the frequency of anterior uveitis (AU) and its correlations in a large cohort of patients with spondyloarthritis (SpA). METHODS: A common protocol of investigation was prospectively applied to 2012 SpA patients in 85 centres from 10 Ibero-American countries. Clinical and demographic variables and disease indexes were investigated. Categorical variables were compared by χ2 and Fisher's exact test, and continuous variables were compared by ANOVA or Kruskal-Wallis test. A value of p<0.05 was considered significant. RESULTS: AU was referred by 372 SpA patients (18.5%). AU was statistically associated with inflammatory low back pain (p<0.001), radiographic sacroiliitis (p<0.001), enthesopathies (p=0.004), urethritis/acute diarrhoea (p<0.001), balanitis (p=0.002), hip involvement (p=0.002), HLA-B27 (p=0.003), and higher C-reactive protein (p=0.001), whilst it was negatively associated with the number of painful (p=0.03) and swollen (p=0.005) peripheral joints, psoriatic arthritis (p<0.001), psoriasis (p<0.001), nail involvement (p<0.001), and dactilitis (p=0.062; trend). No association with gender, race, and indices (disease activity, functionality and quality of life) was observed. Logistic regression showed that ankylosing spondylitis (p=0.001) and HLA-B27 (p=0.083; trend) was significantly associated with AU, while extra-articular manifestations (predominantly psoriasis) were negatively associated (p=0.016). CONCLUSIONS: Anterior uveitis is a frequent extra-articular manifestation in SpA patients, positively associated with axial involvement and HLA-B27 and negatively associated with peripheral involvement and psoriatic arthritis.

Developing a provisional definition of flare in patients with established gout.

OBJECTIVE: Various nonvalidated criteria for disease flare have been used in studies of gout. Our objective was to develop empirical definitions for a gout flare from patient-reported features. METHODS: Possible elements for flare criteria were previously reported. Data were collected from 210 gout patients at 8 international sites to evaluate potential gout flare criteria against the gold standard of an expert rheumatologist definition. Flare definitions based on the presence of the number of criteria independently associated with the flare and classification and regression tree approaches were developed. RESULTS: The mean ± SD age of the study participants was 56.2 ± 15 years, 207 of them (98%) were men, and 54 of them (26%) had flares of gout. The presence of any patient-reported warm joint, any patient-reported swollen joint, patient-reported pain at rest score of >3 (0-10 scale), and patient-reported flare were independently associated with the study gold standard. The greatest discriminating power was noted for the presence of 3 or more of the above 4 criteria (sensitivity 91% and specificity 82%). Requiring all 4 criteria provided the highest specificity (96%) and positive predictive value (85%). A classification tree identified pain at rest with a score of >3, followed by patient self-reported flare, as the rule associated with the gold standard (sensitivity 83% and specificity 90%). CONCLUSION: We propose definitions for a disease flare based on self-reported items in patients previously diagnosed as having gout. Patient-reported flare, joint pain at rest, warm joints, and swollen joints were most strongly associated with presence of a gout flare. These provisional definitions will next be validated in clinical trials.

A community-based study on the prevalence of spondyloarthritis and inflammatory back pain in Mexicans.

BACKGROUND: The prevalence of spondyloarthritis (SpA) varies across populations. In Mexicans, the prevalence of SpA is still unknown. OBJECTIVE: The objective of this study was to determine the prevalence of SpA in the community as well as that of inflammatory back pain (IBP) and ankylosing spondylitis (AS). METHODS: We identified individuals older than 18 years with nontraumatic back pain (BP) in a door-to-door nurse survey using the Community Oriented Program for the Control of Rheumatic Diseases. Then, general physicians and rheumatology fellows selected those likely to have IBP (Berlin criteria). Finally, 2 expert rheumatologists assessed IBP individuals according to clinical data and classification criteria and requested HLA-B27 and radiographic studies to determine the clinical condition of the individual and SpA (European SpA Study Group) classification. RESULTS: The prevalence of BP among 4059 individuals was 14.6% (95% confidence interval [CI], 13.6-15.8). The prevalence of IBP and SpA was 1.3% (95% CI, 1.0-1.7) and 0.6% (95% CI, 0.4-0.9), respectively. Ankylosing spondylitis prevalence was 0.1% (95% CI, 0.02-0.2). Inflammatory back pain and SpA percentage of males and females was similar. The percentage of individuals with IBP according to the 2 experts was lower than that determined by general physicians and rheumatology fellows, but all cases with HLA-B27, radiographic sacroiliitis, SpA, and AS had previous IBP confirmation by the expert. CONCLUSIONS: The prevalence and sex distribution of patients classified with SpA in this community study--as well as that of patients diagnosed with AS--are consistent with those found in recent studies. Expert assessment of individuals with positive responses to questionnaires is relevant for the classification of IBP and SpA.

Differences between early vs. late-onset of psoriatic arthritis: Data from the RESPONDIA and REGISPONSER registries.

OBJECTIVES: The objective was to evaluate the association between the age at onset of psoriatic arthritis (PsA) symptoms with the characteristics and burden of the disease. METHODS: This was an observational and cross-sectional study that included a subgroup of 231 patients with PsA with < 10 years of disease duration from the REGISPONSER and RESPONDIA registries. Patients were divided into two groups according to the age of PsA symptom onset (early onset: ≤ 40-years-old and late onset: ≥ 60-years-old). The characteristics and burden of the disease were compared between the two groups, and multivariate logistic regression was performed to determine the factors independently associated with late-onset PsA. RESULTS: Patients from the early-onset group showed a significantly lower prevalence of males [94 (62.3%) vs. 38 (86.4%)] and a higher prevalence of enthesitis [44 (24.6%) vs. 5 (9.8%)] and sacroiliitis [30 (16.8%) vs. 4 (7.7%)]. Additionally, the early-onset group showed lower scores on the BASFI [2.2 (2.2) vs. 3.3 (2.5)] and minor structural damage (BASRI) in both the spine [1.6 (2) vs. 2.9 (3)] and whole axial skeleton (total BASRI) [1.9 (2.4) vs. 3.4 (3.4)]. In contrast, no statistically significant differences were found between the groups in disease activity evaluated by the BASDAI and ASDAS. Logistic regression analysis showed that late-onset PsA was independently associated with being male (OR 4.4, 95% CI: 1.3, 16.3), greater structural damage (total BASRI) (OR 3.3, 95% CI: 1.3, 8.1), a higher frequency of arthritis in the upper limbs (OR 2.8, 95% CI: 1, 7.7), and greater loss of function (BASFI) (OR 1.3, 95% CI: 1, 1.6). CONCLUSIONS: Patients with late-onset PsA showed different clinical characteristics and greater disease severity than those with early-onset PsA.

Identification of the first signs or symptoms in different spondyloarthritis subtypes and their association with HLA-B27: data from REGISPONSER and RESPONDIA registries.

OBJECTIVE: To describe and analyse the initial symptoms attributable to patients with spondyloarthritis (SpA) and their association with HLA-B27 status. METHODS: This was an observational, cross-sectional and multicentre study with patients who fulfilled the European Spondyloarthropathy Study Group criteria for SpA from the Registry of Spondyloarthritis of Spanish Rheumatology (REGISPONSER) and Ibero-American Registry of Spondyloarthropathies (RESPONDIA) united registries. Differences in the first sign(s) or symptom(s) were compared across diagnoses and between HLA-B27 status. The diagnostic delay between patients who start the disease with musculoskeletal manifestations (MMs) and extra-MMs (EMMs) was compared. RESULTS: A total of 4067 patients were included (2208 from REGISPONSER and 1859 from RESPONDIA) (ankylosing spondylitis (AS): 68.3%, psoriatic arthritis (PsA): 19.9%, undifferentiated SpA: 11.8%). Overall, 3624 (89.1%) patients initiated the disease with MMs and 443 (10.9%) with EMMs. Low back pain (61.7%) and lower-limb arthritis (38.5%) were the most frequent initial symptoms. In AS patients, the absence of HLA-B27 seems to be related to an increase in the probability of starting the disease with cervical pain and peripheral manifestations. In PsA, the onset of arthritis and psoriasis was more prevalent in HLA-B27-negative patients, while initiation with axial manifestations was more predominant in HLA-B27-positive patients. The diagnostic delay was longer in patients with initial MMs than in those with EMMs (7.2 (34.8) vs 4.5 (7.6) years, respectively). CONCLUSION: In this SpA population, MMs were the most prevalent initial symptoms, with differences across diagnoses and depending on the presence of the HLA-B27 antigen.

The impact of short-chain fatty acid-producing bacteria of the gut microbiota in hyperuricemia and gout diagnosis.

INTRODUCTION/OBJECTIVES: Persistent hyperuricemia is a key factor in gout; however, only 13.5% of hyperuricemic individuals manifest the disease. The gut microbiota could be one of the many factors underlying this phenomenon. We aimed to assess the difference in taxonomic and predicted functional profiles of the gut microbiota between asymptomatic hyperuricemia (AH) individuals and gout patients. METHODS: The V3-V4 region of the 16S rRNA gene of the gut microbiota of AH individuals, gout patients, and controls was sequenced. Bioinformatic analyses were carried out with QIIME2 and phyloseq to determine the difference in the relative abundance of bacterial genera among the study groups. Tax4fun2 was used to predict the functional profile of the gut microbiota. RESULTS: AH individuals presented a higher abundance of butyrate- and propionate-producing bacteria than gout patients; however, the latter had more bacteria capable of producing acetate. The abundance of Prevotella genus bacteria was not significantly different between the patients but was higher than that in controls. This result was corroborated by the functional profile, in which AH individuals had less pyruvate oxidase abundance than gout patients and less abundance of an enzyme that regulates glutamate synthetase activation than controls. CONCLUSION: We observed a distinctive taxonomic profile in AH individuals characterized by a higher abundance of short-chain fatty acid-producing bacteria in comparison to those observed in gout patients. Furthermore, we provide scientific evidence that indicates that the gut microbiota of AH individuals could provide anti-inflammatory mediators, which prevent the appearance of gout flares. Key Points • AH and gout patients both have a higher abundance of Prevotella genus bacteria than controls. • AH individuals' gut microbiota had more butyrate- and propionate-producing bacteria than gout patients. • The gut microbiome of AH individuals provides anti-inflammatory mediators that could prevent gout flares.