Treatment Pattern Analysis and Health-care Resource Consumption on Patients with Psoriatic Arthritis or Ankylosing Spondylitis Treated with Biological Drugs in a Northern Italian Region

Purpose: To analyze the treatment patterns of psoriatic arthritis (PSA) or ankylosing spondylitis (AS) patients under biological therapies and to evaluate in this population the health-care resource consumption and related costs.

Patients and methods: A retrospective analysis was performed on administrative databases of the Veneto region. Patients ≥18 years with at least one prescription of biological drugs and a diagnosis at any level for PSA or AS from January 1, 2011 to December 31, 2016 (inclusion period) were included. Index date (ID) was defined as date of first biological drug prescription during inclusion period. Patients were characterized the year before ID and followed-up for one year after ID. The drug utilization profile in terms of adherence, persistence and therapeutic regimen changes, and the health-care resource consumption was analyzed during follow-up.

Results: A total of 2602 patients were included: 1857 with PSA and 745 with AS. In the PSA cohort, 40.3% of patients were prescribed adalimumab, 35.6% etanercept, 8.0% golimumab, 7.5% infliximab, 5.6% ustekinumab and 3.0% certolizumab. Percentage of PSA patients adherent to treatment was higher among ustekinumab patients (91.3%) and lower among etanercept users (54.3%). Persistence ranged from 53.2% (infliximab) to 70.3% (etanercept). Regarding AS cohort, 45.5% of patients were prescribed adalimumab, 26% etanercept, 17.3% infliximab, 9.7% golimumab and 1.5% certolizumab. Adherence ranged from 46.9% (etanercept) to 90.9% (certolizumab) and persistence from 62.8% (adalimumab) to 81.8% (certolizumab). Mean annual health-care costs (including costs for drug treatment, diagnostic services, specialist visits and hospital admissions) ranged from €9727 (certolizumab) to €14,994 (ustekinumab) among PSA patients and from €9875 (infliximab) to €12,991 (golimumab) among AS patients.

Conclusion: This study in Veneto region gave a picture of biological treatment patterns among PSA and AS patients in a real-world setting. Our findings showed the high degree of variability concerning utilization of each biological drug and provided insight on the economic burden of both diseases.