Persistence of Biologics in the Treatment of Psoriatic Arthritis: Data From a Large Hospital-Based Longitudinal...

To analyze the trends in biologics use at a specialized center over a period of 20 years.

We performed a retrospective analysis of 571 patients diagnosed with psoriatic arthritis enrolled in the Toronto cohort who initiated biologic therapy between January 1, 2000, and July 7, 2020. The probability of drug persistence over time was estimated nonparametrically. The time to discontinuation of first and second treatment was analyzed using Cox regression models, whereas a semiparametric failure time model with a gamma frailty was used to analyze the discontinuation of treatment over successive administrations of biologic therapy.

The highest 3-year persistence probability was observed with certolizumab when used as first biologic treatment, while interleukin-17 inhibitors had the lowest probability. However, when used as second medication, certolizumab had the lowest drug survival even when accounting for selection bias. Depression and/or anxiety were associated with a higher rate of drug discontinuation due to all causes (relative risk [RR] 1.68, P = 0.01), while having higher education was associated with lower rates (RR 0.65, P = 0.03). In the analysis accommodating multiple courses of biologics, a higher tender joint count was associated with a higher rate of discontinuation due to all causes (RR 1.02, P = 0.01). Older age at the start of first treatment was associated with a higher rate of discontinuation due to side effects (RR 1.03, P = 0.01), while obesity had a protective role (RR 0.56, P = 0.05).

Persistence in taking biologics depends on whether the biologic was used as first or second treatment. Depression and anxiety, higher tender joint count, and older age lead to drug discontinuation.