Table 1

Characteristics of the early PsA cohort dichotomised by the presence or absence of dactylitis

Characteristics and outcomesNon-dactylitic PsA
(96/177 (54.2%))
Dactylitic PsA
(81/177 (45.8%))
Difference/p value
Clinical
 Age (years), mean (SD)44.4 (12.8)43.7 (13.3)0.7 (−3.2 to 4.5)
 Male38 (39.6%)42 (51.9%)p=0.10
 Symptom duration (months), median (IQR)18.0 (10.5–36.0)12.0 (6.0–24.0)−6.0 (−13.1 to 1.1)
 Duration from diagnosis (months), median (IQR)1.1 (0–2.7)1.2 (0.3–4.6)0.03 (−0.9 to 1.0)
 Symptoms <24 months, patients (%)64/96 (66.7)68/81 (84.0)p=0.008
 Early morning stiffness (min), median (IQR)50.0 (15.0–90.0)60.0 (15.0–180.0)0 (−24.1 to 24.1)
 TJC (78), median (IQR)4.0 (1.0–10)9.0 (5.0–19.0)5.0 (2.0 to 8.0)**
 SJC (76), median (IQR)1.0 (0.0–3.0)7.0 (4.0–13.0)6.0 (4.3 to 7.6)***
 TJC (78) median (IQR) (excluding dactylitis)4.0 (1.0–10.0)5.0 (2.0–11.0)1.0 (−1.4 to 3.4)
 SJC (76) median (IQR) (excluding dactylitis)1.0 (0.0–3.0)3.0 (1.0–6.0)2.0 (0.8 to 3.3)**
 Current psoriasis96/96 (100.0%)74/81 (91.4%)p=0.003**
 Family history of psoriasis52/94 (55.3%)49/78 (62.8%)p=0.32
 PASI, median (IQR)2.9 (0.8–4.9)1.9 (0.4–4.2)−1.2 (−2.4 to 0.0)
 Psoriatic nail dystrophy49/96 (51.0%)44/81 (54.3%)p=0.66
 mNAPSI, median (IQR)2.0 (0.0–7.5)0.0 (0.0–8.0)−2.0 (−3.7 to −27.9)*
 Clinical Enthesitis34/96 (35.4%)42/81 (51.9%)p=0.027*
 MASES score, median (IQR)0.0 (0.0–2.0)1.0 (0.0–2.0)1.0 (0.4 to 1.6)**
 BMI, median (IQR)28.2 (24.0–32.1)28.6 (25.0–31.5)0.3 (−1.7 to 2.4)
 Smoking (current)19 (19.8%)9 (11.1%)p=0.11
Disease phenotype
 Oligoarthritis (defined by SJC <5)83/96 (86.5%)28/81 (34.6%)p<0.001***
 Oligoarthritis (defined by TJC and/or SJC <5)48/96 (50%)29/81 (35.8%)p=0.058
 DIP joint disease7/93 (7.5%)13/77 (16.9%)p=0.058
 Axial disease17/94 (18.1%)9/78 (11.5%)p=0.23
 Arthritis mutilans000
Laboratory markers
 CRP (mg/L), median (IQR)5.0 (5.0–9.3)8.1 (5.0–18.4)3.1 (0.9–5.3)**
 Elevated CRP (>10 mg/L)24/96 (25.0%)36/81 (44.4%)p=0.006**
 ESR, median (IQR)11.0 (5.0–25.0)16.5 (7.0–27.0)7.0 (0.4–13.6)*
Composite outcomes
 DAPSA score, median (IQR)20.8 (12.6, 30.5)24.4 (14.9, 36.5)p=0.07
Patient-reported outcomes (PROs)
 PsAQoL, median (IQR)6.0 (0.0–13.0)6.0 (2.0–12.0)0.0 (−4.1 to 4.1)
 DLQI, median (IQR)3.0 (1.0–9.0)2.0 (1.0–6.0)−1.0 (−3.3 to 1.3)
 HAQ, median (IQR)0.75 (0.25–1.50)0.75 (0.38–1.38)0.125 (−0.23 to 0.48)
  • *p<0.05, **p<0.01, ***p<0.001.

  • BMI, body mass index; CRP, C reactive protein; DAPSA, Disease Activity in Psoriatic Arthritis; DIP, distal interphalangeal; DLQI, Dermatology Quality of Life Index; ESR, erythrocyte sedimentation rate; HAQ, Health Assessment Questionnaire Disability Index; MASES, Maastricht Ankylosing Spondylitis Enthesitis Score; mNAPSI, Modified Nail Psoriasis Severity Index; PASI, Psoriasis Area Severity Index; ; PsA, psoriatic arthritis; PsAQoL, PsA quality of life; SJC, swollen joinr count; TJC, tender joint count.