Outcomes and costs of incorporating a multibiomarker disease activity test in the management of patients with rheumatoid arthritis

Abstract

Objective: The multibiomarker disease activity (MBDA) blood test has been clinically validated as a measure of disease activity in patients with RA. We aimed to estimate the effect of the MBDA test on physical function for patients with RA (based on HAQ), quality-adjusted life years and costs over 10 years.

Methods: A decision analysis was conducted to quantify the effect of using the MBDA test on RA-related outcomes and costs to private payers and employers. Results of a clinical management study reporting changes to anti-rheumatic drug recommendations after use of the MBDA test informed clinical utility. The effect of treatment changes on HAQ was derived from 5 tight-control and 13 treatment-switch trials. Baseline HAQ scores and the HAQ score relationship with medical costs and quality of life were derived from published National Data Bank for Rheumatic Diseases data.

Results: Use of the MBDA test is projected to improve HAQ scores by 0.09 units in year 1, declining to 0.02 units after 10 years. Over the 10 year time horizon, quality-adjusted life years increased by 0.08 years and costs decreased by US$457 (cost savings in disability-related medical costs, US$659; in productivity costs, US$2137). The most influential variable in the analysis was the effect of the MBDA test on clinician treatment recommendations and subsequent HAQ changes.

Conclusion: The MBDA test aids in the assessment of disease activity in patients with RA by changing treatment decisions, improving the functional status of patients and cost savings. Further validation is ongoing and future longitudinal studies are warranted.

Keywords: biomarkers; health economics; outcome assessment; quality of life; rheumatoid arthritis.

Fig. 1

HAQ distribution: current clinical practice vs MBDA at year 1 Dark grey: current clinical practice; light grey: with Vectra DA. Shift of the curve, to the left, denotes improvement in the mean HAQ score with the use of the MBDA test (year 1). MBDA: multibiomarker disease activity; PDF: probability density function.

Fig. 2

Mean HAQ progression over a 10-year time horizon with and without MBDA test adjunct Dark grey: current clinical practice; light grey: with Vectra DA. MBDA: multibiomarker disease activity.

Fig. 3

One-way sensitivity analysis (effect on costs) Lower and upper bounds for parameters presented in the supplementary data, available at Rheumatology Online. All variables were analysed in the one-way sensitivity analysis, however, only those showing a difference >US$10 (between the upper and lower bound) were included in the figure. All costs reported in 2014 US dollars. AEs: adverse events; MBDA: multibiomarker disease activity; sDMARDs: synthetic DMARDs.

Fig. 4

Probabilistic sensitivity analysis (A) Incremental costs vs incremental QALYs. (B) Probability that cost per QALY gained is less than or equal to the willingness-to-pay threshold per QALY gained. MBDA: multibiomarker disease activity; QALY: quality-adjusted life years.