Differences between men and women with nonradiographic axial spondyloarthritis: clinical characteristics and treatment effectiveness in a real-life prospective cohort

BACKGROUND

Sex differences with regard to clinical manifestations and response to tumor necrosis factor inhibitors (TNFi) have been delineated for the radiographic form of axial spondyloarthritis (axSpA). More limited evidence for a differential effectiveness of treatment in genders exists for the nonradiographic disease state (nr-axSpA). The aim of the study was to compare demographics, clinical parameters, and response to TNFi in women versus men with nr-axSpA.

METHODS

We compared disease characteristics of 264 women and 231 men with nr-axSpA at inclusion in the prospective Swiss Clinical Quality Management Cohort. Response to a first TNFi was assessed in 85 women and 78 men without diagnosed co-morbid fibromyalgia. The primary outcome was the proportion of patients achieving the 40% improvement in the Assessment of SpondyloArthritis international Society criteria (ASAS40) at 1 year. Additional response outcomes were evaluated as secondary outcomes. Patients having discontinued TNFi were considered non-responders. Logistic regression analyses were adjusted for baseline differences, which might potentially mediate the effect of sex on treatment response.

RESULTS

Compared to men, women had a longer diagnostic delay, a higher level of perceived disease activity, and more enthesitis and were in a lower percentage HLA-B27 positive. An ASAS40 response was achieved by 17% of women and 38% of men (OR 0.34; 95% CI 0.12, 0.93; p = 0.02). A significantly lower response rate in women was confirmed in the adjusted analysis (OR 0.19; 95% CI 0.05, 0.62; p = 0.009) as well as for the other outcomes assessed.

CONCLUSION

Despite only few sex differences in patient characteristics in nr-axSpA, response rates to TNFi are significantly lower in women than in men.

Understanding the paradigm of non-radiographic axial spondyloarthritis

The concept of axial spondyloarthritis (axSpA) encompasses both non-radiographic (nr-axSpA) and traditional radiographic axSpA (r-axSpA) forms. The former was conceived following the establishment of the ASAS classification criteria for axSpA, which for the first time included the use of magnetic resonance imaging of the sacroiliac joints. This facilitated the classification of patients with axSpA who did not present substantial structural damage. This conception of nr-axSpA revolutionized the classical understanding of axSpA opening new doors for research and broadening the scope of treatment to the entire spectrum of axSpA. In this sense, epidemiologic patterns of the disease were viewed anew, and early diagnosis became a primary objective in the management of the disease. However, despite these advances, this new axSpA subtype led to some concerns within the scientific community. These issues have been addressed by several studies that set out to clarify the concept of nr-axSpA. In this review, we summarize the findings of the most relevant studies including nr-axSpA and then discuss recent advances in understanding disease clinical patterns, burden of disease, and treatment effects. Current scientific research has shown subtle differences between nr-axSpA and r-axSpA. In the near future, these advances will allow for better management of individual patients across the axSpA spectrum.

Comorbid fibromyalgia impairs the effectiveness of biologic drugs in patients with psoriatic arthritis

OBJECTIVES

To evaluate the impact of FM on the clinical outcomes of biologics in patients with PsA in real life.

METHODS

FM was diagnosed according to current criteria among PsA patients starting a first biologic drug from 2010 through 2017. At each visit, disease activity of PsA (DAPSA), minimal disease activity (MDA), HAQ, rate of patients achieving DAPSA-based low disease activity (LDA) or remission, and MDA were evaluated. Lost patients or those not achieving the target were imputed as non-responders. The drug survival was evaluated by Kaplan-Meyer analysis. Estimated hazard ratios (HRs) of discontinuing therapy or achieving MDA were assessed by multivariate regression models.

RESULTS

A total of 238 patients, of whom 58 had also FM, started a first biologic drug. Compared with no-FM PsA, FM PsA patients were more frequently female (P = 0.0001) with polyarticular subset (P = 0.0001), and with higher mean BMI (P = 0.006). Drug survival was significantly lower in FM PsA (50%, mean 32 months) than in no-FM PsA (74%, mean 42 months, P = 0.0001). Rates of remission/LDA and MDA were significantly lower in FM PsA at 3, 6, 12 and 24 months (P < 0.001). Remission in FM PsA was negligible (3.4% and 0% at 3 and 6 months, respectively). Negative predictors of drug discontinuation were no FM (HR 0.51) and normal weight (HR 0.29), while no FM (HR 2.54) and male sex (HR 1.58) were positive predictors of long-standing MDA.

CONCLUSIONS

Comorbid FM, along with female gender and obesity seem to be the worst combination of negative prognostic factors in PsA.

Are we treating women patients with real axial spondyloarthritis?

INTRODUCTION

During the last years, regulatory agencies raised some relevant concerns with regard to the possibility of administrating biological therapy (BT) to non-SpA patients. Especially, the possibility of treating women with fibromyalgia as non-radiographic axSpA (nr-axSpA) was mentioned.

OBJECTIVES

To evaluate if the gender distribution and clinical pattern of patients with axSpA initiating biological therapy (BT) was modified in clinical practice after its approval for non radiographic-axSpA (nr-axSpA).

METHODS

Baseline dataset from a prospective ongoing cohort including all patients with axSpA treated with BT at the Rheumatology Department of University Hospital La Paz, Madrid, Spain, was analysed. Patient's characteristics and disease activity parameters were collected. Based on the approval indication date of BT for nr-axSpA, patients were classified in two periods according to the starting date for the first BT: period 1 (before 2013) and period 2 (during or after 2013). Gender distribution and disease' characteristics were compared between both groups using Chi-square and Student-t tests.

RESULTS

In total, 385 patients initiated BT: 266 (69%) in period 1 and 119 (31%) in period 2. No significant differences between both periods were observed regarding gender distribution (38% and 39% of women; p = 0.8). Out of those patients with nr-axSpA initiating BT in period 2, the majority (60%) were men. Women starting BT in period 2 had significantly higher systemic inflammation and mobility restriction compared with women in period 1 [median (interquartile range) CRP 10.2 mg/l (3.0-24.9) vs 3.2 mg/l (2.0-9.4); p = 0.02 and BASMI 2.7 (1.8-3.5) vs. 2.0 (1.2-2.6); p = 0.01, respectively]. In addition, they also presented significantly higher disease activity [BASDAI 6.5 (5.4-8.0) vs. 5.8 (4.6-6.8); p = 0.02; ASDAS, mean (SD) 3.6 ± 3.4 vs. 3.2 ± 1.0; p = 0.02, respectively] and more functional limitation [BASFI 5.7 (3.8-6.7) vs. 4.3 (2.0-6.1); p = 0.01, respectively] than men treated in period 2.

CONCLUSIONS

In our clinical practice, the frequency of women who started BT did not increase since their approval for nr-axSpA. Women treated with BT after 2012 had more objective disease activity parameters than before their approval for nr-axSpA treatment.

How to investigate: Early axial spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic inflammatory condition of the axial skeleton that encompasses radiographic and non-radiographic axSpA and that can lead to chronic pain, structural damage, disability, and loss of quality of life. Scientific advances, including the role of MRI assessment, have led to new diagnostic insights and the creation of a new set of classification criteria for axial and peripheral SpA. New criteria allow the identification of SpA patients with early disease and their enrolment in clinical studies. In this chapter, we discuss the difference between diagnostic and classification criteria, the diagnostic approach to patients with suspected axSpA, the limitations of MRI assessment, and the importance of early identification of this condition. A practical algorithm to investigate axSpA, based on the current evidence, is also proposed. Clinical judgement should always be kept as the mainstay in the diagnosis of axSpA.

The Impact of Fibromyalgia in Spondyloarthritis: From Classification Criteria to Outcome Measures

The term spondyloarthritis (SpA) encompasses a broad clinical spectrum characterized by chronic inflammatory conditions affecting the sacroiliac joints, the spine but also peripheral joints and tendons and being additionally associated with the involvement of organs, such as bowel, eye and skin (1). Musculoskeletal pain is a key symptom in SpA. However, although low back pain and/or joint pain are characteristic for SpA, undifferentiated pain at different enthesial sites may also be a concomitant or even the first clinical presentation in some patients (2). In addition, fatigue is another important symptom often reported by patients with SpA, which substantially affects the quality of life (QoL) (3). Fibromyalgia (FM) is the most common diagnosis in patients complaining of chronic diffuse pain with fatigue and may occur alone or in association with chronic inflammatory diseases (4). The prevalence of FM ranges from 2 to 8% in the general population and it can reach up to over 50% in patients with other rheumatic and musculoskeletal diseases (RMDs) (5-7). FM has been identified as the most disabling RMD, based on the patients' perception that their medical condition is not properly recognized (8). This is also due to the poor knowledge about its pathogenesis, and therefore the lack of reliable biomarkers reveals a major unmet need requiring to be addressed in further research studies. Over the last decade, an increasing body of evidence described the impact of FM in SpA highlighting the pitfalls for correct classification, appropriate differential diagnosis and assessment of outcome measures in both conditions. The purpose of this review is to provide an overview of currently available data with regard to the coexistence and reciprocal features of FM and SpA.