The value of persistence in treatment with subcutaneous TNF-alpha inhibitors for ankylosing spondylitis

Eur J Health Econ. 2020 Feb;21(1):45-54. doi: 10.1007/s10198-019-01110-w. Epub 2019 Sep 14.

Abstract

Objective: To estimate the impact of persistence on cost-effectiveness of subcutaneous tumor necrosis factor-α inhibitors (SC-TNFis) from healthcare and societal perspectives in a United Kingdom ankylosing spondylitis (AS) population using a recently published Markov cohort model.

Methods: A recently published cost-effectiveness model developed for a National Institute for health and Care Excellence appraisal was extended to fit the current study; in brief, it is a Markov cohort model where treatment responders continue from the trial period with maintenance SC-TNFi treatment, while non-responders transition to conventional care. Costs and effects were modeled for a hypothetical SC-TNFi with average efficacy and price. Model outcomes included quality-adjusted life-years (QALYs), total direct and indirect lifetime costs, and incremental cost-effectiveness ratios (ICERs). The cost-effectiveness of SC-TNFi persistence was estimated by decreasing the annual discontinuation probability in five percentage point increments from 25 to 5% per annum.

Results: From a health care perspective, the ICERs for the modeled discontinuation rates compared to the baseline annual discontinuation rate (25%) ranged between GBP 17,277 and GBP 18,161. From a societal perspective, increased discontinuation rates resulted in decreased total costs and higher QALYs; hence, lower discontinuation rates dominated higher discontinuation rates from a societal perspective.

Conclusion: In conclusion, this study shows that, all else equal, higher SC-TNFi treatment persistence in AS is cost effective from a health care perspective and dominant from a societal perspective. Hence, all else equal, prescribing the SC-TNFi with the highest persistence may be considered a cost-effective strategy.

Keywords: Ankylosing spondylitis; Bechterew’s disease; Cost–benefit analysis; Economic evaluation; Medication persistence.

MeSH terms

  • Assessment of Medication Adherence*
  • Cost-Benefit Analysis
  • Female
  • Humans
  • Injections, Subcutaneous
  • Male
  • Markov Chains
  • Models, Econometric
  • Quality-Adjusted Life Years
  • Severity of Illness Index
  • Spondylitis, Ankylosing / drug therapy*
  • Tumor Necrosis Factor Inhibitors / administration & dosage
  • Tumor Necrosis Factor Inhibitors / economics*
  • Tumor Necrosis Factor Inhibitors / therapeutic use*
  • United Kingdom

Substances

  • Tumor Necrosis Factor Inhibitors