Short summary

The aim is to identify clinical phenotypes of Spondyloarthropathy (SpA) and ultimately elucidate prognostic factors of importance to patients and physicians alike. This insight will be important for rheumatologists in the perspective of making individualized treatment strategies, prognostic stratification and patient counseling.

Rationale

Spondyloarthopathies (SpA) is a heterogeneous group of chronic rheumatic diseases with overlapping symptoms including psoriatic arthritis (PsA), ankylosing spondylitis (AS) arthritis associated with inflammatory bowel disease (enteropathic arthritis), reactive arthritis and undifferentiated SpA.

SpA can be dominated by peripheral joint involvement, classified as peripheral SpA, or by inflammatory back pain, classified as axial SpA (ax-SpA). Furthermore ax-SpA is subdivided into two groups: Nonradiographic and radiographic. The Assessment of Spondyloarthritis International Society (ASAS) has made a set of criteria for recognizing patients with early ax-SpA to optimize treatment and to reduce the risk of irreversible joint damage. Next to the spinal and articular symptoms, many patients with SpA also have extra-articular manifestations which contribute to reduced quality of life. In AS first line of therapy is non-steroidal anti-inflammatory drug (NSAID), but in patients with simultaneous inflammatory bowel disease (IBD) these should be administered with caution as some studies have suggested that they exacerbate intestinal inflammation. Early induction of an anti-TNF therapy among these patients is recommended. Furthermore enthesitis is a typical feature in SpA and the treatment of these manifestations seem to be challenging as well. Studies have showed that anti-TNF therapy is superior to conventional DMARD in patients with longstanding enthesitis. Uveitis is an acute inflammation of the uvea and is a common and potential serious extra-articular manifestation in patients with SpA. In most cases acute uveitis can be successfully treated by the opthalmologists with local corticosteroids, but in some cases it develops into a refractory uveitis, and treatment with TNFi is recommended (as azathioprine and methotrexate do not have sufficient effect on the disease activity of SpA).

We anticipate that extra-articulare manifestations among patients with SpA is underestimated and therefore undertreated, and contributes to a reduced quality of life. Spondyloarthritic disorders are generally diagnosed more often in men than in women. In reference to the most representative form of these disorders, ankylosing spondylitis, three male cases are documented for every female case. However, since the introduction of the new ASAS criteria for axial spondyloarthropathies these differences are no longer so apparent. SpA appears to be more frequent in men than in women, particularly in its axial presentations. Nevertheless, little is known of the differential clinical expression of SpA between males and females. The explanation for these differences is not clear, and the participation of multifactorial parameters cannot be discarded. A few studies have analysed gender as a prognostic factor of the SpA , and there is a need to determine the particularities and severity of SpA in the female gender. We hypothesise that the amount of self-reported disease activity is more pronounced in woman than in men. The overall objective of this cross-sectional study is to perform a characterization of SpA patients, to identify clinical phenotypes of SpA and ultimately elucidate factors pre­dictive of disease outcome. This insight will be important for rheumatologists in the perspective of making individualized treatment strategies, prognos­tic stratification and patient counseling.

Description of the cohort

The study will be designed as a cross-sectional cohort design with prospective enrolment of patients with SpA over time. Information about the patients and their exposures will be collected at a single centre at one visit according to the clinical standards in Denmark.

Patients with any disease of the SpA spectrum seen in the Department of Rheumatology, Odense University Hospital, Svendborg/Odense will be asked if they want to participate in the trial. To be considered for inclusion, participants must have the ability and willingness to give written informed consent and to meet the requirements of this protocol.

Exclusion criteria

1. Age under 18 years
2. No consent
3. Patient does not understand Danish

Data and biological material

Measures to be collected:

• Medical history
• Physical examination
• Biochemistry (peripheral blood)
• HLA-B27 (peripheral blood)
• DANBIO registration
• Informed consent
• Charlson Comorbidity Index
• SF-36
• Faecal calprotectin (mg/L) (stool sample)
• Urine electrolytes (urine sample)

Collaborating researchers and departments

Department of Medicine, Section of Rheumatology, Odense University Hospital, Svendborg

• Inger Marie Jensen Hansen, MD, DMSc, PhD

OPEN Odense Patient data Explorative Network, Odense University Hospital

Department of Rheumatology, Odense University Hospital

• Professor Torkell Ellingsen, MD, PhD

Department of Medicine, Section of Gastroenterology, Odense University Hospital, Svendborg

• Claus Aalykke, MD, PhD 

The Parker Institute, Department of Rheumatology, Bispebjerg and Frederiksberg Hospital, The Capital Region of Copenhagen

• Professor and Senior Biostatistician Robin Christensen, MSc, PhD

• Lars Erik Kristensen, MD, PhD