Health-Care and Societal Costs Associated with Non-Persistence with Subcutaneous TNF-α Inhibitors in the Treatment of Inflammatory Arthritis (IA): A Retrospective Observational Study

Abstract

Objective: A few studies have suggested that patients with inflammatory arthritis (IA) who remain persistent with subcutaneous TNF-α inhibitors (SC-TNFi) incur lower health care costs than patients who discontinue treatment, whereas data on the impact of non-persistence on indirect costs are largely lacking. Furthermore, existing estimates are based on fixed follow-ups, in relation to treatment initiation, and therefore do not measure costs in direct relation to treatment discontinuation. Therefore, by capturing costs in direct relation to treatment discontinuation, this study aimed to estimate direct and indirect costs associated with non-persistence with SC-TNFis in IA. Methods: Adult Swedish biologic-naïve IA patients initiating biologic treatment with a SC-TNFi (adalimumab, etanercept, certolizumab or golimumab) between May 6, 2010, and December 31, 2017, were identified in population-based registers with almost complete coverage. IA was defined as a diagnosis of rheumatic arthritis, ankylosing spondylitis/unspecified spondyloarthritis or psoriatic arthritis. Non-persistent patients were matched on propensity score to patients persistent with treatment by at least an additional 12 months. This enabled comparisons of direct healthcare costs and indirect costs for sick leave and disability pension, respectively, 12 months before and 12 months after treatment discontinuation. Results: A balanced cohort of 486 matched pairs was generated. The total direct and indirect costs were significantly higher among non-persistent patients already during the 12 months before index ($20,802 [18,335–23,429] vs. $16,600 [14,331–18,696]). However, while non-persistent patients increased their total direct and indirect costs, persistent patients significantly decreased the same, further widening the difference in costs during the 12-month period after index date ($22,161 [19,754–24,556] vs. $13,465 [11,415–15,729]). Conclusions: Among biologic-naïve Swedish IA patients treated with SC-TNFis, persistent patients incurred about 40% lower aggregated direct and indirect costs compared to non-persistent patients the year following SC-TNFi discontinuation. This highlights the impact of treatment persistence from an economic viewpoint, adding further aspects to the clinical perspective. Graphical Abstract: [Figure not available: see fulltext.]