OBJECTIVES:To analyze therapeutic pathways and persistence to treatment of biodrugs-treated patients affected by psoriatic arthritis(PsA) or ankylosing spondylitis(AS) and to evaluate healthcare resources consumption and related costs for the Regional Health System.

METHODS:A retrospective analysis was performed on administrative databases of Veneto region. Patients ≥18 years were included if having at least one prescription of biodrugs (ATC L04A) together with a diagnosis at any level for PSA(ICD9CM/exemption code 696.0/0.45.696.0) or AS(ICD9CM/exemption code 720.0/0.54.720.0) from 01/01/2011 to 31/12/2016 (inclusion period). Index date(ID) was defined as date of first biodrug prescription during inclusion period. Patients were characterized the year before ID and followed-up for one year after ID. Persistence was defined as presence of biodrugs prescription during last trimester of follow-up.

RESULTS:2,602 patients (1,857 PsA and 745 AS) were included. Concerning PSA cohort, patients were treated: 40.3% with adalimumab, 35.6% etanercept, 8.0% golimumab, 7.5% infliximab, 5.6% ustekinumab and 3.0% certolizumab. Mean age ranged from 50.9 (golimumab) to 54.7 (etanercept); male proportion ranged from 43.6% (certolizumab) to 68.3% (infliximab). Persistence ranged from 53.2% (infliximab) to 70.3% (etanercept). Regarding AS cohort, 45.5% of patients were treated with adalimumab, 26% etanercept, 17.3% infliximab, 9.7% golimumab and 1.5% certolizumab treatments. Mean age ranged from 44.9 (adalimumab) to 49.7 (certolizumab). Males percentage ranged from 57.8% (adalimumab) to 72.7% (certolizumab). Persistence ranged from 62.8% (adalimumab) to 81.8% (certolizumab).Mean annual healthcare costs (including costs for drug treatment, diagnostic services, specialist visits and hospital admissions) ranged from 9,727€ (certolizumab) to 14,994€ (ustekinumab) among PSA-patients and from 9,875€ (infliximab) to 12,991€ (golimumab) among AS-patients.

CONCLUSIONS:Our results gave a picture of biological treatment pattern, persistence to treatment and healthcare cost among patients affected by PsA and AS in a real-world setting. Further investigations could be performed to consider a larger sample and the adoption of new biological and biosimilar drugs.