Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose: To determine if demographic and disease characteristics of patients with PsA at presentation to a PsA clinic cluster into distinct groups.
Methods: 1058 patients with Psoriatic Arthritis (PsA) were included from an observational cohort. Cluster analysis using Ward’s method was conducted to identify groups of patients based on the following characteristics at baseline: gender, type of psoriasis (type I or II), duration of PsA, race, family history of psoriasis, ESR, severe PASI, psoriasis vulgaris, nail disease, dactylitis, swollen joint count, damage joint count, axial disease, and presence of arthritis prior to psoriasis. 7 clusters were formed and matched to non-overlapping arthritis patterns (as described previously) at first clinic visit: distal arthritis, oligoarthritis, polyarthritis, axial only, distal arthritis and axial, oligoarthritis & axial, and polyarthritis & axial. Comparisons between the clusters and arthritis patterns were conducted using t-tests and Chi-square analysis.
Results: The baseline characteristics of the 1058 patients were as follows: 613 (56.5%) males, mean age at diagnosis of PsA 37.1 (13.5) years, mean age at first visit 44 (13.1) years, mean duration of PsA 6.8 (8.2) years, mean active joint count 11.0 (9.8), mean PASI 5.8 (8.3), mean Steinbrocker score 12.9 (25.5), HLA-B*27 116(17.7%)] with an average follow-up of 8.4 (8.4) years. Two main clusters of patients were identified. One consisted of distal arthritis, oligoarthritis and polyarthritis and the other of axial only, distal and axial, oligoarthritis & axial, and polyarthritis & axial, thus clearly identifying patients into peripheral and axial disease. Comparison of the two clusters showed a longer duration of PsA at baseline, more patients with a family history of psoriasis, and more dactylitis in patients with peripheral disease. Patients falling into the axial disease cluster had a higher prevalence of males, more Caucasians, more psoriasis vulgaris, worse PASI score), higher damage joint count and more patients who developed arthritis first.
Conclusion: Based on patients’ characteristics at baseline, cluster analysis separated PsA patients into two main arthritis patterns- axial and peripheral. The study provides further evidence to classify patients into just two groups based on the presence or absence of axial arthritis.
Table: Comparison of two clusters
|
Variable |
Frequency (%) or Mean (sd) |
p-value |
|
|
Cluster I |
Cluster II |
||
|
Age at diagnosis of Ps (>40 vs. <=40) |
63 (14.5%) |
47 (20.4%) |
0.06 |
|
Duration of PsA |
8.6 (7.6) |
5.0 (6.5) |
<0.0001 |
|
Gender (Males) |
259 (59.4%) |
175 (76.1%) |
<0.0001 |
|
Race (Caucasian vs. others) |
365 (84.1%) |
208 (90.8%) |
0.02 |
|
Family history of Psoriasis |
124 (28.6%) |
33 (14.4%) |
<0.0001 |
|
Nail disease |
214 (69.7%) |
120 (78.4%) |
0.06 |
|
Dactylitis |
236 (54.4%) |
80 (34.8%) |
<0.0001 |
|
Abnormal skin |
352 (82.4%) |
213 (94.3%) |
<0.0001 |
|
Severe PASI (>=10) |
35 (12.9%) |
40 (27.2%) |
0.0003 |
|
ESR |
21.7 (18.9) |
28.5 (22.1) |
0.0002 |
|
Swollen joint count |
3.3 (4.2) |
2.8 (3.9) |
0.12 |
|
Damage joint count |
1.1 (2.9) |
7.6 (11.8) |
<0.0001 |
|
Axial disease |
67 (15.5%) |
208 (90.4%) |
<0.0001 |
|
Arthritis first |
20 (4.6%) |
21 (9.1%) |
0.02 |
Disclosure:
A. Thavaneswaran,
None;
V. Chandran,
None;
D. D. Gladman,
None.
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