Structural entheseal lesions in psoriasis predicted later progression to psoriatic arthritis (PsA), according to cohort study data published in Arthritis & Rheumatology. In the same cohort, low cortical volumetric bone mineral density (vBMD) at entheseal sites was also associated with progression to PsA.
The prospective cohort study enrolled patients with psoriasis receiving care at the Dermatology Department of the University of Erlangen-Nuremberg in Erlangen, Germany. Recruitment took place from January 2011 to July 2018; patients with psoriasis without evidence of musculoskeletal involvement were selected for inclusion. At baseline, a clinical assessment of structural entheseal lesions and volumetric bone mineral density (vBMD) at entheseal and intra-articular sites was performed using high-resolution peripheral quantitative computed tomography (HR-pQCT). Demographics data, psoriasis severity, disease duration, psoriasis subtype, and laboratory figures were also measured. Patients were evaluated at annual follow-up visits. The primary outcome measure was clinical diagnosis of PsA, defined as the presence of inflammatory musculoskeletal involvement and the achievement of at least 3 points of the Classification Criteria for Psoriatic Arthritis. Cox regression analyses were conducted to assess the risk for PsA by baseline entheseal lesion status. Incidence of PsA was also calculated by lesion status.
A total of 114 patients with psoriasis were enrolled, of whom 72 were men (63.2%). Mean age at enrollment was 45.3±13.9 years, and mean follow-up duration was 28.2±17.7 months. At baseline, 41 patients (36%) had at least 1 structural entheseal lesion in their metacarpophalangeal joints. Overall, 24 patients (21%) developed PsA during follow-up, for an incidence rate of 9.7 cases per 100 person-years. Incidence of PsA in patients with entheseal lesions was 21.4 per 100 person-years, compared with just 4.2 per 100 person-years in patients without lesions. The adjusted hazard ratio (HR) for PsA in patients with structural lesions was 5.10 (95% confidence interval [CI], 1.53-16.99; P =.008) compared with patients without lesions. In unadjusted Cox models, each 1-standard deviation increase in baseline entheseal vBMD corresponded to a 30% reduction in risk for PsA. In particular, greater cortical vBMD at entheseal segments corresponded with a reduced risk for PsA (HR, 0.64; 95% CI, 0.42-0.98). Associations remained significant after adjustment for covariates and multiple imputation for missing data. Baseline intra-articular vBMD was not significantly correlated with risk for progression to PsA.
As study limitations, investigators cited the small cohort size and even smaller proportion of patients who developed PsA. Replication in a larger cohort is necessary to further explore progression to PsA in patients with entheseal lesions in psoriatic disease.
“These data may be relevant to clinicians seeking to forecast progression to PsA in patients with psoriasis,” the researchers noted. Structural entheseal lesions and low cortical vBMD at entheseal segments were the most significant risk factors for later PsA.
Simon D, Tascilar K, Kleyer A, et al. Structural entheseal lesions in patients with psoriasis are associated with an increased risk of progression to psoriatic arthritis [published online February 26, 2020]. Arthritis Rheumatol. doi: 10.1002/art.41239