Adherence to Antitumor Necrosis Factor Use Recommendations in Spondyloarthritis: Measurement and Effect in the DESIR Cohort

J Rheumatol. 2017 Oct;44(10):1436-1444. doi: 10.3899/jrheum.161399. Epub 2017 Jul 1.

Abstract

Objective: To evaluate a classification system to define adherence to axial spondyloarthritis (axSpA) anti-tumor necrosis factor (anti-TNF) use recommendations and examine the effect of adherence on outcomes in the DESIR cohort (Devenir des Spondylarthropathies Indifférenciées Récentes).

Methods: Using alternate definitions of adherence, patients were classified as adherent "timely" anti-TNF users, nonadherent "late" anti-TNF users, adherent nonusers ("no anti-TNF need"), non-adherent nonusers ("unmet anti-TNF need"). Multivariate models were fitted to examine the effect of adherence on quality-adjusted life-years (QALY), total costs, and nonbiologic costs 1 year following an index date. Generalized linear regression models assuming a γ-distribution with log link were used for costs outcomes and linear regression models for QALY outcomes.

Results: Using the main definition of adherence, there were no significant differences between late anti-TNF users and timely anti-TNF users in total costs (RR 0.86, 95% CI 0.54-1.36, p = 0.516) or nonbiologic costs (RR 0.72, 95% CI 0.44-1.18, p = 0.187). However, in the sensitivity analysis, late anti-TNF users had significantly increased nonbiologic costs compared with timely users (RR 1.58, 95% CI 1.06-2.36, p = 0.026). In the main analysis, there were no significant differences in QALY between timely anti-TNF users and late anti-TNF users, or between timely users and patients with unmet anti-TNF need. In the sensitivity analysis, patients with unmet anti-TNF need had significantly lower QALY than timely anti-TNF users (-0.04, 95% CI -0.07 to -0.01, p = 0.016).

Conclusion: The effect of adherence to anti-TNF recommendations on outcomes was sensitive to the definition of adherence used, highlighting the need to validate methods to measure adherence.

Keywords: ADHERENCE; ANKYLOSING SPONDYLITIS; ANTI-TNF; ECONOMIC; QUALITY OF LIFE; SPONDYLOARTHRITIS.

MeSH terms

  • Adult
  • Antirheumatic Agents / therapeutic use*
  • Biological Products / therapeutic use*
  • Cohort Studies
  • Female
  • Humans
  • Male
  • Medication Adherence*
  • Middle Aged
  • Spondylarthritis / drug therapy*
  • Tumor Necrosis Factor-alpha / antagonists & inhibitors*
  • Young Adult

Substances

  • Antirheumatic Agents
  • Biological Products
  • Tumor Necrosis Factor-alpha