High sensitivity C-reactive as a disease activity parameter in patients

High sensitivity C-reactive as a disease activity parameter in patients

Thema: 3 x 3 (3 Slides in 3 Minutes) Abstract Präsentationen - II
50.11
High sensitivity C-reactive as a disease activity parameter in patients with ankylosing
spondylitis and non-radiographic axial spondyloarthritis
Poddubnyy D.1, Rudwaleit M.2, Listing J.3, Braun J.4, Sieper J.5
(1) Charité Universitätsmedizin Berlin - Campus Benjamin Franklin, Medizinische Klinik I, Rheumatologie,
Berlin, (2) Charité Universitätsmedizin Berlin - Campus Benjamin Franklin, Medizinische Klinik I
Gastroenterologie, Infektologie, Rheumatologie, Berlin, (3) Deutsches Rheuma-Forschungszentrum (DRFZ),
Berlin, (4) Rheumazentrum Ruhrgebiet, St. Josefs-Krankenhaus, Herne, (5) Charité Universitätsmedizin
Berlin - Campus Benjamin-Franklin, Medizinische Klinik I,Gastroenterologie/Immunologie/ Rheumatologie,
Berlin
Zielsetzung
In ankylosing spondylitis (AS) only 40-60% of patients have elevated serum concentrations of C-reactive
protein (CRP). AS patients with "normal" values of standard CRP may well have active disease according to
clinical parameters. High sensitivity C-reactive protein (hsCRP) quantifies levels of CRP in the "subnormal"
range of concentrations and therefore can outperform standard CRP as a disease activity parameter in
patients with ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (SpA).
Methodik
305 patients (168 with AS and 137 with non-radiographic axial SpA) from the German Spondyloarthritis
Inception Cohort (GESPIC) were included. hsCRP levels were measured using particle-enhanced
immunoturbidimetric method (Roche) with the lowest detected level of 0.1 mg/l. hsCRP values were
compared to results of routine turbidimetric CRP test.
Ergebnisse
The correlation (Spearman's Rho coefficient) between hsCRP and routine CRP values in the whole group of
patients was 0.757 (p<0.001). 163 patients (53.4%) had a level of routine CRP below the upper normal limit
(<6 mg/l).
In the group of patients with AS and level of routine CRP <6 mg/l there was a clear trend for an increase of
pain, stiffness, and functional impairment with an increase of hsCRP concentration (table). Such trend was
less pronounced in patients with non-radiographic axial SpA.
AS
Axial SpA
hsCRP, mg/l 0-1.9 (n=45)
2.0-3.9 (n=18) 4.0-5.9 (n=11) 0-1.9 (n=57)
2.0-3.9 (n=17) 4.0-5.9 (n=5)
Spinal pain, 4.0 (3.2-4.8)
cm VAS
5.6 (4.5-6.7)
5.6 (3.8-7.3)
5.0 (4.3-5.8)
4.5 (3.0-6.0)
6.4 (4.3-8.5)
Night pain,
cm VAS
3.3 (2.5-4.2)
4.8 (3.6-6.1)
5.2 (3.3-7.1)
4.5 (3.7-5.4)
4.9 (3.1-6.7)
6.8 (2.7-10.9)
Morning
3.7 (2.8-4.6)
stiffness, cm
VAS
4.9 (3.6-6.3)
4.6 (3.1-6.2)
4.3 (3.5-5.1)
4.0 (2.5-5.5)
5.0 (0.8-9.2)
BASDAI
3.4 (2.7-4.1)
4.3 (3.1-5.5)
4.2 (2.6-5.7)
3.7 (3.1-4.3)
3.6 (2.5-4.7)
4.2 (2.1-6.3)
BASFI
2.4 (1.6-3.1)
3.0 (2.0-4.0)
3.4 (1.4-5.4)
2.2 (1.6-2.8)
2.5 (1.5-3.6)
1.9 (1.0-2.9)
Clinical parameters (mean and 95% CI) in patients with normal level of routine CRP
Statistically significant correlations were found between hsCRP and intensity of night back pain (Rho=0.244,
p=0.029), and the presence of enthesitis (Rho=0.230, p=0.041) in AS patients.
In the total population of AS patients (n=163), hsCRP correlated better than standard CRP with parameters
of disease activity: level of pain (Sperman's Rho=0.307 vs 0.224), spinal pain (0.243 vs, 0.165), night back
pain (0.301 vs 0.248), morning stiffness (0.210 vs 0.158), BASFI (0.247 vs 0.214), BASMI (0.251 vs 0.232),
and the presence of uveitis (0.190 vs 0.166). Neither CRP nor hsCRP correlated significantly with total
BASDAI.
In the group of patients with a pre-radiographic axial SpA significant correlations were found only for between
level of hsCRP and intensity of discomfort in tender areas (BASDAI question 4): Rho=0.199, p=0.022.
Schlussfolgerung
High sensitivity CRP correlates better than standard CRP with clinical disease activity parameters in patients
with AS and non-radiographic axial SpA. Within the "normal" range of routine CRP (<6 mg/l) parameters of
disease activity tended to rise with increase of hsCRP. Therefore hsCRP could be superior to standard CRP
in assessing disease activity in axial SpA.