The Incidence and Risk Factors for Psoriatic Arthritis in Patients With Psoriasis: A Prospective Cohort Study

Abstract

Objective. To estimate the incidence of psoriatic arthritis (PsA) in patients with psoriasis, and to identify risk factors for its development.Methods. The study was designed as a prospective cohort study involving psoriasis patients who did not have a diagnosis of arthritis at the time of study enrollment. Information was collected about lifestyle habits, comorbidities, psoriasis activity, and medications. Patients who developed inflammatory arthritis or spondylitis were classified as having PsA if they fulfilled the criteria of the Classification of Psoriatic Arthritis Study group. The annual incidence of PsA was estimated using an event per person-years analysis. Cox proportional hazards models, involving fixed and timedependent explanatory variables, were fitted to obtain estimates of the relative risk (RR) of the onset of PsA, determined in multivariate models stratified by sex and controlled for age at onset of psoriasis.Results. The data obtained from the 464 patients who were followed up for 8 years were analyzed. A total of 51 patients developed PsA during the 8 years since enrollment. The annual incidence rate of PsA was 2.7 cases (95% confidence interval 2.1-3.6) per 100 psoriasis patients. The following baseline variables were associated with the development of PsA in multivariate analysis: severe psoriasis (RR 5.4, P 5 0.006), low level of education (university/college versus high school incomplete RR 0.22, P 5 0.005; high school graduate versus high school incomplete RR 0.30, P 5 0.049), and use of retinoid medications (RR 3.4, P 5 0.02). In multivariate models with time-dependent variables, psoriatic nail pitting (RR 2.5, P 5 0.002) and uveitis (RR 31.5, P 5 0.0002) were associated with the development of PsA.Conclusion. The incidence of PsA in patients with psoriasis is higher than previously reported. A severe psoriasis phenotype, presence of nail pitting, low level of education, and uveitis are predictive of the development of PsA in patients with psoriasis.

Subclinical joint inflammation in patients with psoriasis without concomitant psoriatic arthritis: a cross-sectional and longitudinal analysis

“…Hence, more than half of the patients with concomitant presence of arthralgia as well as positive MRI changes, but only 15% of patients without such changes developed PsA. Transition of psoriasis into PsA was rather high in our study as compared with other studies,27 which may be based on accumulation of more severe cases including those with beginning joint involvement in the highly specialised care setting of an University Clinic. Nonetheless, these findings indicate the possibility to define patients with psoriasis, in which preventive treatment for the development of PsA may be feasible 28.…”

Incidence and prevalence of psoriatic arthritis in Denmark: a nationwide register linkage study

“…Until now, only one prospective study has been published of patients with psoriasis developing PsA. The study reported a constant risk in these patients 11. Indeed, this finding was corroborated by a cross-sectional observational study of 1560 patients with psoriasis, of which 126 had PsA 19…”

“…While recent data suggest an incidence rate ranging from 3.6 to 7.2 per 100 000 person-years, older studies have reported a much wider incidence range (ie, from 0.1 to 23.1 per 100 000 person-years) 6–10. The most recent study and the only prospective study of PsA in patients with psoriasis demonstrated an annual incidence of 2.8% 11. Consequently, the incidence and temporal trends of PsA in the general population remain poorly understood.…”

Physical trauma recorded in primary care is associated with the onset of psoriatic arthritis among patients with psoriasis

“…A recent prospective cohort study by Eder et al 28 confirmed psoriatic nail lesions and psoriasis severity as risk markers of PsA, while identifying uveitis and low level of education as novel predictors. As more risk factors become elucidated, a risk profile for PsA would enable clinicians to diagnose and provide treatment earlier.…”