Data collection
Data collection was carried out before the initiation of the biologic,
at the same time of blood samples collection and 6 months later. It
concerned:
-Demographics: age, sex, body mass index (BMI)
-Disease activity information’s: erythrocyte sedimentation rate (ESR),
C-reactive protein (CRP), the diseased activity score in 28 joints
(DAS28) for RA patients [19], the bath ankylosing spondylitis
disease activity index (BASDAI) [10] and the ankylosing spondylitis
disease activity score (ASDAS) [11] for SpA patients and the Harvey
Bradshaw index (HBI) [12] for CD patients.
We divided patients into responders and non-responders. For RA patients,
DAS28 < 2.6 means remission, DAS28 between 2.6 and 3.2 means
low disease activity, DAS28 between 3.2 and 5.1 means moderate activity
and DAS 28 > 5.1 means high activity [9]. Patients in
remission or low disease activity were considered as responders, and
others as non-responders.
For SpA patients, ASDAS (calculated with CRP) < 1.3 means
inactive disease, ASDAS between 1.3 and 2.1 means moderate disease
activity, ASDAS between 2.1 and 3.5 means high disease activity and
ASDAS > 3.5 means very high disease activity [11].
Patients with inactive disease or moderate disease activity were
considered as responders, and others as non-responders.
For CD patients, responders were those whom HBI decreased to 4 points or
less or by 3 points or less from baseline [12].
-Data related to the treatment: the type of TNF alpha blocker, duration
of intake, levels and frequency of intake and concomitant use of
conventional synthetic disease modifying anti rheumatic drugs
(csDMARDs).