PT - JOURNAL ARTICLE AU - Sayam Dubash AU - Oras A Alabas AU - Xabier Michelena AU - Leticia Garcia-Montoya AU - Richard J Wakefield AU - Philip S Helliwell AU - Paul Emery AU - Dennis G McGonagle AU - Ai Lyn Tan AU - Helena Marzo-Ortega TI - Dactylitis is an indicator of a more severe phenotype independently associated with greater SJC, CRP, ultrasound synovitis and erosive damage in DMARD-naive early psoriatic arthritis AID - 10.1136/annrheumdis-2021-220964 DP - 2022 Apr 01 TA - Annals of the Rheumatic Diseases PG - 490--495 VI - 81 IP - 4 4099 - http://ard.bmj.com/content/81/4/490.short 4100 - http://ard.bmj.com/content/81/4/490.full SO - Ann Rheum Dis2022 Apr 01; 81 AB - Objective To characterise the impact of dactylitis in disease-modifying antirheumatic drug (DMARD)-naive early psoriatic arthritis (PsA).Methods Patients with early PsA meeting the classification criteria for PsA (CASPAR) were recruited. Clinical outcomes were recorded, and ultrasonography was conducted to assess grey scale (GS) and power Doppler (PD) synovitis, periarticular cortical bone erosions and enthesitis. The cohort was dichotomised by the presence or absence of dactylitis.Results Of 177 patients with PsA, those with dactylitis (dactylitic PsA (81/177, 46%)) had higher tender joint count (p<0.01), swollen joint count (SJC) (p<0.001) and C reactive protein (CRP) (p<0.01) than non-dactylitic PsA. Dactylitis was more prevalent in toes (146/214 (68.2%)) than fingers (68/214 (31.8%)); ‘hot’ dactylitis was more prevalent than ‘cold’ (83.6% vs 16.4%). Ultrasound (US) synovitis and erosions were significantly more prevalent in dactylitic PsA (p<0.001 and p<0.001, respectively). Exclusion of dactylitis in dactylitic PsA confirmed significantly greater SJC (3 vs 1, p=0.002), US synovitis (GS ≥2: 20.6% vs 16.1%, p<0.001, or PD ≥1: 5.1% vs 3.3%, p<0.001) and erosions (1.1% vs 0.5% joints, p=0.008; 26.1% vs 12.8% patients, p=0.035%) than non-dactylitic PsA. Synovitis (GS ≥2 and/or PD ≥1) occurred in 53.7% of dactylitis. No substantial differences were observed for US enthesitis.Conclusion Dactylitis signifies a more severe disease phenotype independently associated with an increased disease burden with greater SJC, CRP, US-detected synovitis and bone erosions in DMARD-naive early PsA and may be a useful discriminator for early risk stratification.Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information. The data underlying this article are available in the article and in its online supplementary material.