Osteoarthritis (OA) is one of the most common joint disorders. Evidence suggests that the infrapatellar fat pad (IFP) is directly involved in OA pathology. However, a comparison between OA versus non-OA IFP is still missing. Thus, the aim of this study was to compare IFP molecular, adipocytes and extracellular matrix characteristics of patients affected by OA, and patients undergoing anterior cruciate ligament (ACL) reconstruction. We hypothesized that not only inflammation but also changes in adipocytes and extracellular matrix (ECM) composition might be involved in OA pathogenesis. Fifty-three patients were enrolled. IFP biopsies were obtained, evaluating: (a) lymphocytic infiltration and vascularization; (b) adipocytes area and number; (c) adipo-cytokines and extracellular matrix gene expression levels; (d) IL-6 and VEGF protein production; (e) collagen fibers distribution. OA IFP was more inflamed and vascularized compared to ACL IFP. OA IFP adipocytes were larger and numerically lower (1.3-fold) than ACL IFP adipocytes. An increase of gene expression of typical white adipose tissue genes was observed in OA compared to ACL IFP. Collagen-types distribution was different in the OA IFP group compared to controls, possibly explaining the change of the biomechanical characteristics found in OA IFP. Statistical linear models revealed that the adipocyte area correlated with BMI in the OA group. In conclusion, inflammation and fibrotic changes of OA IFP could represent novel therapeutic targets to counteract OA.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV2) was characterized at the end of 2019, and soon spread around the world, generating a pandemic. It has been suggested that men are more severely affected by the viral disease (COVID-19) than women. The aim of this systematic literature review (SRL) and meta-analysis was to analyse the influence of gender on COVID-19 mortality, severity, and disease outcomes. A SRL was performed in PubMed and Embase, searching terms corresponding to the ‘PEO’ format: population = adult patients affected with COVID-19; exposure = gender; outcome = any available clinical outcomes by gender, including mortality and disease severity. The search covered the period from January 1 to April 30, 2020. Exclusion criteria were: case reports/series, reviews, commentaries, languages other than English. Full-text, original articles were included. Data on study type, country, and patients’ characteristics were extracted. Study quality was evaluated using the Newcastle–Ottawa scale (NOS). From a total of 950 hits generated by the database search, 85 articles fulfilling the inclusion criteria were selected. A random-effects meta-analysis was performed to compare mortality, recovery rates, and disease severity in men compared with women. The male to female ratio for cases was 1:0.9. A significant association was found between male sex and mortality (OR = 1.81; 95% CI 1.25–2.62), as well as a lower chance of recovery in men (OR = 0.72; 95% CI 0.55–0.95). Male patients were more likely to present with a severe form of COVID-19 (OR = 1.46; 95% CI 1.10–1.94). Males are slightly more susceptible to SARS-CoV2 infection, present with a more severe disease, and have a worse prognosis. Further studies are warranted to unravel the biological mechanisms underlying these observations.

Objective: Calcium pyrophosphate deposition (CPPD) disease is prevalent and has diverse presentations, but there are no validated classification criteria for this symptomatic arthritis. The American College of Rheumatology (ACR) and EULAR have developed the first‐ever validated classification criteria for symptomatic CPPD disease.Methods: Supported by the ACR and EULAR, a multinational group of investigators followed established methodology to develop these disease classification criteria. The group generated lists of candidate items and refined their definitions, collected de‐identified patient profiles, evaluated strengths of associations between candidate items and CPPD disease, developed a classification criteria framework, and used multi‐criterion decision analysis to define criteria weights and a classification threshold score. The criteria were validated in an independent cohort.Results: Among patients with joint pain, swelling, or tenderness (entry criterion) whose symptoms are not fully explained by an alternative disease (exclusion criterion), the presence of crowned dens syndrome or calcium pyrophosphate crystals in synovial fluid are sufficient to classify a patient as having CPPD disease. In the absence of these findings, a score >56 points using weighted criteria, comprising clinical features, associated metabolic disorders, and results of laboratory and imaging investigations, can be used to classify as CPPD disease. These criteria had a sensitivity of 92.2% and specificity of 87.9% in the derivation cohort (190 CPPD cases, 148 mimickers), whereas sensitivity was 99.2% and specificity was 92.5% in the validation cohort (251 CPPD cases, 162 mimickers).Conclusion: The 2023 ACR/EULAR CPPD disease classification criteria have excellent performance characteristics and will facilitate research in this field.

Emerging evidence suggests that axial spondyloarthritis (axSpA) should not be seen as a predominantly male disease, as the non-radiographic form occurs with roughly equal frequency in women and men. However, men and women experience this disease differently. The purpose of this review is to highlight sex-associated and gender-associated differences in the patient’s journey through the diagnosis and management of axSpA, in order to increase the awareness about the unmet needs of female axSpA patients. Female patients experience a longer diagnostic delay compared with men, possibly due to the different pattern of clinical presentations across genders. Therefore, it is crucial to sensitise physicians to pay attention and identify the red flags of axSpA in women and promote early referral to a rheumatologist. Women with a diagnosis of axSpA experience greater limitations in physical function, although they have less structural spinal damage compared with men. Women tend to have less adherence and a lower response to treatment, so more gender-oriented data are needed about drugs used for axSpA, especially biological disease-modifying antirheumatic drugs. Lifestyle factors have a strong impact on the disease course. Interventions regarding physical activity, smoking cessation and diet should be communicated to the patients, with particular attention to the gender-related cultural background. Patients of childbearing age living with axSpA should be engaged in a discussion about reproductive health, in terms of preservation of fertility, management of pregnancy and delivery and use of biologic drugs during pregnancy and breastfeeding.

Objective Calcium pyrophosphate deposition (CPPD) disease is prevalent and has diverse presentations, but there are no validated classification criteria for this symptomatic arthritis. The American College of Rheumatology (ACR) and EULAR have developed the first-ever validated classification criteria for symptomatic CPPD disease. Methods Supported by the ACR and EULAR, a multinational group of investigators followed established methodology to develop these disease classification criteria. The group generated lists of candidate items and refined their definitions, collected de-identified patient profiles, evaluated strengths of associations between candidate items and CPPD disease, developed a classification criteria framework, and used multi-criterion decision analysis to define criteria weights and a classification threshold score. The criteria were validated in an independent cohort. Results Among patients with joint pain, swelling, or tenderness (entry criterion) whose symptoms are not fully explained by an alternative disease (exclusion criterion), the presence of crowned dens syndrome or calcium pyrophosphate crystals in synovial fluid are sufficient to classify a patient as having CPPD disease. In the absence of these findings, a score>56 points using weighted criteria, comprising clinical features, associated metabolic disorders, and results of laboratory and imaging investigations, can be used to classify as CPPD disease. These criteria had a sensitivity of 92.2% and specificity of 87.9% in the derivation cohort (190 CPPD cases, 148 mimickers), whereas sensitivity was 99.2% and specificity was 92.5% in the validation cohort (251 CPPD cases, 162 mimickers). Conclusion The 2023 ACR/EULAR CPPD disease classification criteria have excellent performance characteristics and will facilitate research in this field.