What Clinical Factors Affect Length of Transition to Psoriatic Arthritis in Patients With Psoriasis?

Objective We aimed to identify clinical and demographic features associated with the interval between psoriasis (PsO) and psoriatic arthritis (PsA). Methods We identified patients with PsO and PsA diagnoses from our tertiary care psoriatic disease biorepository: a longitudinal, real‐world database including clinical information and patient‐reported outcomes. We used a multivariable a zero‐inflated negative binomial model to evaluate several clinical and demographic features that may be associated with the time between PsO and PsA onset. Results A total of 384 patients were included, of whom 52.2% were female. The mean age of PsO onset was 31.5 years. Advanced age at PsO onset was associated with a shorter interval between PsO and PsA. Based on our model, patients with PsO onset at age 42.6 years (upper end of the interquartile range [IQR]) had a 62% shorter expected interval compared with patients with PsO onset at age 18.9 years (lower end of IQR) ( P < 0.001) and were more likely to have concurrent (onset within 6 months) diagnoses (odds ratio 4.56; 95% confidence interval 2.9–7.17). Patients with a body mass index (BMI) of 34 compared with a BMI of 26 had a 10% shorter interval between PsO and PsA, which trended toward statistical significance ( P = 0.053). Conclusion Our study demonstrated that patients with a diagnosis of PsO at an older age have a shorter interval between PsO and PsA diagnoses and are more likely to have concurrent diagnoses compared with patients with an onset of PsO at a younger age. These results suggest that patients with a later onset of PsO may benefit from earlier PsA screening.