Costs associated with failure to respond to treatment among patients with rheumatoid arthritis initiating TNFi therapy: a retrospective claims analysis

Abstract

Background: Tumor necrosis factor inhibitors (TNFi) are common second-line treatments for rheumatoid arthritis (RA). This study was designed to compare the real-world clinical and economic outcomes between patients with RA who responded to TNFi therapy and those who did not.

Methods: For this retrospective cohort analysis we used medical and pharmacy claims from members of 14 large U.S. commercial health plans represented in the HealthCore Integrated Research Database. Adult patients (aged ≥18 years) diagnosed with RA and initiating TNFi therapy (index date) between 1 January 2007 and 30 April 2014 were included in the study. Treatment response was assessed using a previously developed and validated claims-based algorithm. Patients classified as treatment responders in the 12 months postindex were matched 1:1 to nonresponders on important baseline characteristics, including sex, age, index TNFi agent, and comorbidities. The matched cohorts were then compared on their all-cause and RA-related healthcare resource use, and costs were assessed from a payer perspective during the first, second, and third years postindex using parametric tests, regressions, and a nonparametric bootstrap.

Results: A total of 7797 patients met the study inclusion criteria, among whom 2337 (30%) were classified as treatment responders. The responders had significantly lower all-cause hospitalizations, emergency department visits, and physical/occupational therapy visits than matched nonresponders during the first-year postindex. Mean total all-cause medical costs were $5737 higher for matched nonresponders, largely driven by outpatient visits and hospitalizations. Mean all-cause pharmacy costs (excluding costs of biologics) were $354 higher for matched nonresponders. Mean RA-related pharmacy costs (conventional synthetic and biologic drugs), however, were $8579 higher in the responder cohort, driven by higher adherence to their index TNFi agent (p < 0.01 for all comparisons). A similar pattern of cost differentiation was observed over years 2 and 3 of follow-up.

Conclusions: In this real-world study we found that, compared with matched nonresponders, patients who responded to TNFi treatments had lower all-cause medical, pharmacy, and total costs (excluding biologics) up to 3 years from initiation of TNFi therapy. These cost differences between the two cohorts provide a considerable offset to the cost of RA medications and should encourage close monitoring of treatment response to minimize disease progression with appropriate therapy choices.

Keywords: Biologic; Healthcare costs; Healthcare resource use; Real-world observational study; Rheumatoid arthritis; Treatment response.

Fig. 1

Cost differences between responders and nonresponders during 1 year follow-up (n = 2337 per cohort). All-cause medical costs include all costs related to inpatient and outpatient visits, such as office visits and laboratory testing. All-cause pharmacy costs include all costs related to outpatient pharmacy fills, with the exception of fills for biologic drugs (defined as abatacept, adalimumab, anakinra, certolizumab pegol, etanercept, golimumab, infliximab, rituximab, tocilizumab, and tofacitinib citrate). Rheumatoid arthritis (RA)-related medical costs include all costs related to inpatient and outpatient visits, such as office visits and laboratory testing, with International Classification of Diseases, Ninth Revision, Clinical Modification, codes for RA noted on the claims. RA-related pharmacy costs include all costs related to outpatient pharmacy fills for conventional synthetic disease-modifying antirheumatic drugs and biologics

Fig. 2

All-cause total healthcare costs (excluding biologics) during 1, 2, and 3 years of follow-up (n = 542 per cohort). Costs are derived from a matched sample of patients with ≥3 years of continuous health plan enrollment from the index date (n = 542 per cohort). p values are derived from t tests comparing mean costs across cohorts within each year. Medical costs include all costs related to inpatient and outpatient visits, such as office visits and laboratory testing. Pharmacy costs include all costs related to outpatient pharmacy fills, with the exception of fills for biologic drugs (defined as abatacept, adalimumab, anakinra, certolizumab pegol, etanercept, golimumab, infliximab, rituximab, tocilizumab, and tofacitinib citrate)

Fig. 3

Rheumatoid arthritis (RA)-related total healthcare costs during 1, 2, and 3 years of follow-up (n = 542). Costs are derived from a matched sample of patients with ≥3 years of continuous health plan enrollment from the index date (n = 542 per cohort). p values are derived from t tests comparing mean costs across cohorts within each year. Medical costs include all costs related to inpatient and outpatient visits, such as office visits and laboratory testing, with International Classification of Diseases, Ninth Revision, Clinical Modification, codes for RA noted on the claims. Pharmacy costs include all costs related to outpatient pharmacy fills for conventional synthetic disease-modifying antirheumatic drugs and biologics