OBJECTIVES : To describe patients initiating their first biologic therapy for ankylosing spondylitis (AS) and compare their economic outcomes to a cohort of patients treated with non-biologic therapy in a population-based claims database.

METHODS : A longitudinal analysis of Taiwan’s National Health Insurance Database from 1/1/2014 through 12/31/2017 was conducted. An index period from 1/1/2015 through 12/31/2015 identified patients with claims for AS (ICD-9-CM: 720.0) and a biologic (ATC = L04ABXX) with no previous claims for a biologic in the year prior to their first biologic claim during the index period. Patients were indexed upon their first biologic claim in 2015 and followed through the end of the study period (12/31/2017). A cohort of patients with AS and a claim for an NSAID (AS + NSAID) in 2015 was matched to the biologic cohort based on age, gender, and Charlson comorbidity index. All non-pharmacy direct costs (inpatient, outpatient, and emergency room) in the database were recorded in NT$ for both cohorts during years one and two of follow-up.

RESULTS : There were 430 AS patients initiating a biologic in 2015 and 1,678 AS + NSAID patients in the matched cohort included in the study. Patients in the biologic cohort had a mean (SD) age of 41.9 (14.1) and were mostly male (72.1%). During the first year of follow-up, costs averaged NT$53,885 for the biologic cohort and NT$56,893 for the matched cohort. Average costs declined from year one to year two by 15.2% and 4.3% in the biologic and matched cohorts, respectively. Average costs in the first year of follow-up were NT$47,852 for golimumab (n=117), NT$51,958 for adalimumab (n=191), and NT$62,689 for etanercept (n=122).

CONCLUSIONS : Treatment of AS with biologics reduced non-medication costs at a greater rate than the matched cohort of AS patients treated with NSAIDs.