Table 2

Clinical parameters between patients with PsA isolated axial disease versus those with isolated axial AS with psoriasis at first presentation of axial disease

VariableIsolated axial PsA (N=32)Isolated axial AS with psoriasis (N=82)P value
Demographics
 Age43.09 (14.06)36.92 (12.57)0.035
 Male (%)71.8873.171
 Caucasian (%)87.5076.830.362
 Age at diagnosis of PsA/AS in years37.44 (12.36)29.65 (11.25)0.003
 Smoker (%)59.3839.020.079
Clinical features
 Enthesitis* (%)3.137.320.671
 Elevated ESR (%)39.2925.000.256
 PASI6.06 (8.00)1.72 (2.08)0.030
 BSA10.13 (18.30)4.61 (9.03)0.328
 Nail lesion (%)53.136.06<0.001
 Uveitis (%)18.7534.150.166
 Inflammatory bowel disease* (%)6.2518.290.146
 Inflammatory back pain† (%)50.0077.330.021
Back metrology‡
 Neck rotation (degrees)67.81 (22.80)66.57 (22.96)0.849
 Lateral flexion, Domjan method (degrees)15.03 (5.78)13.49 (5.95)0.344
 Schober test (cm)4.07 (1.65)4.00 (1.61)0.870
 Chest expansion (cm)5.67 (2.76)4.99 (2.04)0.230
Comorbidities
 BMI26.61 (6.08)25.96 (4.50)0.696
 Cardiovascular disease* (%)12.506.100.265
 Diabetes* (%)7.413.700.597
Patient reported outcomes
 BASDAI1.97 (1.73)4.23 (2.59)0.002
  Fatigue2.90 (2.51)5.05 (2.82)0.027
  Spinal pain1.50 (1.90)4.92 (3.04)<0.001
  Joint pain/swelling1.30 (1.49)2.93 (2.86)0.011
  Areas of localised tenderness1.40 (1.84)3.86 (3.29)0.002
  Morning stiffness severity2.70 (2.58)4.67 (3.15)0.047
  Morning stiffness duration2.80 (3.16)4.08 (3.45)0.256
 HAQ0.16 (0.29)0.59 (0.58)<0.001
 SF-36 physical46.75 (10.36)39.14 (10.47)0.041
 SF-36 mental52.68 (8.66)45.33 (12.53)0.027
Human leucocyte antigen (HLA) types
 HLA-B*27 (%)34.6275.95<0.001
Medications
 NSAIDs (%)50.0060.980.392
 DMARDs (%)28.1310.980.049
 Biologics (%)18.7559.76<0.001
  • Where applicable, figures reported as mean (SD); % denotes percentage of patients in the respective groups.

  • *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.

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

  • 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.