title: Persistence and costs with subcutaneous TNF-alpha inhibitors in immune-mediated rheumatic disease stratified by treatment line.
abstract: OBJECTIVE
  The objectives of this study were to 1) describe and compare treatment persistence with first- and second-line subcutaneous tumor necrosis factor-alpha inhibitors (SC-TNFis) in patients with ankylosing spondylitis (AS), psoriatic arthritis (PsA), or rheumatoid arthritis (RA) (collectively immune-mediated rheumatic disease) in Sweden and 2) estimate and contrast health care costs in the two groups.
  
  
  METHODS
  Patients who initiated their first or second SC-TNFi between May 6 2010 and December 12 2012 were identified from the Prescribed Drug Register. Persistence was estimated using survival analysis. Costs comprised specialized outpatient care, inpatient care, and medication. The persistence analysis was stratified by immune-mediated rheumatic disease diagnosis.
  
  
  RESULTS
  A total of 4,903 patients treated with their first and 845 patients treated with their second SC-TNFi were identified. Baseline characteristics differed between the two groups. Therefore, propensity score matching analysis was implemented. Second-line patients were matched to first-line patients, and four cohort pairs (AS, PsA, RA, and all diagnoses combined) were generated. Patients treated with their first SC-TNFi had statistically significant higher persistence than patients treated with their second SC-TNFi in PsA (P=0.036), RA (P=0.048), and all diagnoses combined (P<0.001) but not in AS (P=0.741). Patients who were treated with their second SC-TNFi incurred higher costs than patients treated with their first SC-TNFi.
  
  
  CONCLUSIONS
  Overall, persistence to the first SC-TNFi was higher than persistence to the second SC-TNFi. Furthermore, the second SC-TNFi was associated with higher costs than the first SC-TNFi. Therefore, prescribing the SC-TNFi with the best long-term persistence first may be beneficial.
authors.affiliation: Mapi Group, Stockholm, Sweden.
authors.forename: Axel
authors.initials: A
authors.lastname: Svedbom
authors.affiliation: Mapi Group, Stockholm, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Dalén
authors.affiliation: Merck & Co., Inc., Kenilworth, NJ, USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Black
authors.affiliation: Merck & Co., Inc., Kenilworth, NJ, USA.
authors.forename: Sumesh
authors.initials: S
authors.lastname: Kachroo
keywords: ankylosing spondylitis; biologics; persistence; psoriatic arthritis; rheumatic disease; rheumatoid arthritis