Ankylosing spondylitis (AS) is a common disease that causes pain and affects productivity. Tumor necrosis factor-α (TNF-α) like adalimumab can bring better clinical efficacy and improve quality of life. Adalimumab is likely to be covered by health insurance. It is necessary to assess the impact of adalimumab for patients with AS on the medical insurance budget in China. Our research aims to give support evidence for policy-making.

From the perspective of medical insurance payers, a budget impact model was established to evaluate the impact of adalimumab for the treatment of adults with severe active AS that has responded inadequately to conventional therapy. The time horizon was 5 years (2020–2024). The cost of measurement included drug and treatment costs for adverse events. Scenario analysis was conducted to evaluate the results under different drug price reimbursement ratios and treatment ratios.

Based on the current price of adalimumab (CNY 3,160 [USD 446]/unit), under the reimbursement ratio of 70 percent, adalimumab will increase medical insurance expenditure by CNY 162 [USD 22] million, CNY 152 [USD 21] million, CNY 114 [USD 16] million, CNY 100 [USD 14] million and CNY 88.11 [USD 12] million in the next 1–5 years, respectively. The increased medical insurance expenditure accounts for 0.091, 0.085, 0.064, 0.056, and 0.049 percent of the annual medical insurance expenditure in the next 1–5 years, respectively, which is assumed to be equivalent to the expenditure in 2018 of CNY 1782.2 [USD 251] billion.

The budget impact of adalimumab for AS on medical insurance expenditure is limited, and including adalimumab in the medical insurance catalogue can reduce the burden on individuals, enrich treatment options, and satisfy clinical needs better.