Amsterdam Spondyloarthritis cohort (AmSpA cohort)

Background: In 1999 a prospective cohort study (Early SpA cohort) was
initiated in Amsterdam (Reade) with inclusion of consecutive early SpA patients
who either fulfilled the modified New York criteria of Ankylosing Spondylitis
(AS) or the ESSG criteria of SpA and had a disease duration of less than two
years, of which currently, 275 patients are included. From 2002 onwards several
cohorts were established consisting of AS patients who were treated with a TNF
inhibitor (TNFi), for each separate type of drug (infliximab (50 patients),
etanercept (203 patients), adalimumab (165 patients) and golimumab (30
patients)). These separated studies necessitated new inclusion procedures
(informed consent included) if a patient switched from one TNFi to another. In
2013, we also established a new non-radiographic axial SpA cohort (as follow up
to the PREVAS study, 80 patients). In addition, from 2017onwards, patients
with axial SpA are treated with other TNFi (certolizumab) and other
biologicals, like interleukin 17 inhibitors (secukinumab a.o.) who are not yet
included in a cohort study. To enhance long term follow-up, all SpA patients,
regardless which type of medication, will be included in the AmSpA cohort. This
will prevent repeating informed consent procedures regarding, basically, the
same study procedure.

To establish one large overarching cohort including all types of SpA (both
non-radiographic, radiographic axial SpA and peripheral SpA) regardless of the
disease stage and treatment and to longitudinally asses several disease aspects
of SpA. The aims of the AmSpA-cohort are:
1) to follow each SpA patient longitudinally and assess the efficacy and
possible adverse events of treatment with biologicals (regardless which type)
in comparison with biological naive SpA patients. Results will be stratified
for gender.
2) to assess the disease course including (radiographic) progression,
occurrence of extra-articular manifestations (EAM) (such as anterior uveitis)
and comorbidity (such as osteoporosis and cardiovascular disease) and the
influence of treatment on the course of these features and comorbidity.
Results will be stratified for gender.

All patients fulfilling the classification of spondyloarthritis according to
the ASAS classification criteria and/or modified New York criteria from two
Amsterdam Rheumatology immunology Center (ARC) partners, i.e. Reade| Jan van
Breemen Institute and the VU University Medical Center will be included. In the
future, the Amsterdam Medical Center (AMC), the third ARC partner, will be
added to the AmSpA cohort. Patients are followed prospectively according to a
clearly defined protocol with regular visits to collect clinical data. During
daily clinical practice data on presence of extra-articular disease
manifestations, disease activity (BASMI, 44 joint count, MASES, VAS physician,
ASDAS), hemodynamic parameters (blood pressure, pulse frequency) and
anthropometrical parameters (weight, hip/waist circumference) were collected.
In addition, questionnaires on disease activity (BASDAI, VAS pain, patient
global disease activity and physical functioning (BASFI) were collected.
Radiological assessment will be performed every two years in case of biological
use in non-radiographic SpA patients and every 5 years in patients without
biological treatment and AS patients. Measurement of bone mineral density (DEXA
scans) will be performed every 5 years. Additionally, for study purpose, three
questionnaires (wellbeing, health care consumption and work participation) and
biobanking every year were collected. All test will be performed by a
physician or a research nurse.

The additional *burden* for the patient consists of an extra blood sample
obtained during routine patient care and three additional questionnaires. The
other mentioned parameters were obtained during routine daily clinical practice
in the rheumatology departments. *