Table 1

Clinical parameters between patients with PsA isolated axial disease versus those with concomitant peripheral disease at first presentation of axial disease

VariableIsolated axial group (N=32)Axial and peripheral group (N=463)P value
Demographics
 Age43.09 (14.06)45.54 (13.22)0.346
 Male (%)71.8863.280.431
 Caucasian (%)87.5085.530.963
 Age at diagnosis of PsA in years37.44 (12.36)35.06 (13.36)0.302
 Age at diagnosis of psoriasis in years25.78 (17.31)27.32 (14.31)0.627
 Smoker (%)59.3846.650.226
Clinical features
 Sacroiliitis grade*2.75 (0.67)2.59 (0.69)0.189
 Enthesitis† (%)3.1314.900.068
 Elevated ESR (%)39.2946.710.560
 PASI6.06 (8.00)7.29 (9.61)0.517
 BSA10.13 (18.30)9.79 (18.01)0.946
 Nail lesion (%)53.1374.950.013
 Uveitis (%)18.759.720.185
 Inflammatory bowel disease† (%)6.257.781.000
 Inflammatory back pain‡ (%)50.0033.960.172
Back metrology§
 Neck rotation (degrees)67.81 (22.80)71.84 (20.81)0.506
 Lateral flexion, Domjan method (degrees)15.03 (5.78)15.58 (4.54)0.709
 Schober test (cm)4.07 (1.65)4.52 (1.31)0.263
 Chest expansion (cm)5.67 (2.76)5.35 (2.65)0.551
Comorbidities
 BMI26.61 (6.08)29.26 (6.61)0.101
 Cardiovascular disease† (%)12.5018.360.485
 Diabetes† (%)7.417.191.000
Patient-reported outcomes
 BASDAI1.97 (1.73)4.65 (2.58)<0.001
  Fatigue2.90 (2.51)5.32 (2.87)0.015
  Spinal pain1.50 (1.90)4.45 (3.20)<0.001
  Joint pain/swelling1.30 (1.49)4.61 (2.84)<0.001
  Areas of localised tenderness1.40 (1.84)4.41 (2.99)<0.001
  Morning stiffness severity2.70 (2.58)4.35 (3.11)0.084
  Morning stiffness duration2.80 (3.16)3.60 (3.02)0.462
 HAQ0.16 (0.29)0.68 (0.61)<0.001
 SF-36 physical46.75 (10.36)36.61 (12.07)0.009
 SF-36 mental52.68 (8.66)46.50 (12.11)0.042
Human leucocyte antigen (HLA) types
 HLA-B†27 (%)34.6221.460.188
 HLA-B†38† (%)15.3815.661
 HLA-B†39† (%)08.840.152
 HLA-B†8† (%)11.5419.950.442
 HLA-B†13 (%)11.547.320.435
 HLA-B†40† (%)01.521
 HLA-C†6 (%)23.0825.380.977
Medications
 NSAIDs (%)50.0069.980.031
 DMARDs (%)28.1347.300.055
 Biologics (%)18.7513.390.558
  • Where applicable, figures reported as mean (SD); % denotes percentage of patients in the respective groups;

  • *The sacroiliac joint with the highest grade was used preferentially for analysis.

  • †Fisher’s exact test used due to low sample size in each sub-group.

  • ‡Low back pain or neck pain and stiffness for more than 3 months that improves with exercise but is not relieved by rest.

  • §The side with the lowest numeric value was used preferentially for analysis, where applicable.

  • BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BMI, body mass index; BSA, body surface area of psoriasis; DMARD, disease-modifying antirheumatic drug; ESR, erythrocyte sedimentation rate; HAQ, Health Assessment Questionnaire; NSAID, nonsteroidal anti-inflammatory drug; PASI, psoriasis area and severity index; PsA, psoriatic arthritis; SF-36, Short Form Health Survey.