Factors associated with biological and targeted synthetic disease-modifying antirheumatic drug initiation for rheumatoid arthritis in underserved patient groups in England and Wales, UK: a national cohort study.

Background: Quantifying health-care inequality is essential to addressing the imbalance in outcomes attributable to age, sex, race or ethnicity, and multimorbidity. In this study, we analysed differences in the initiation of biological or targeted synthetic disease-modifying antirheumatic drugs (DMARDs) in patients with rheumatoid arthritis within the universal health-care system of England and Wales, UK.

Methods: An observational cohort study was conducted using the National Early Inflammatory Arthritis Audit (NEIAA) dataset. We included all patients with rheumatoid arthritis who were enrolled in NEIAA between May 8, 2018, and April 30, 2022, and who had 12-month follow-up data available. Modified Poisson regression was used to explore factors associated with the initiation of biological and targeted synthetic DMARDs within 12 months of initial rheumatology assessment. The factors evaluated included age, sex, ethnicity, socioeconomic status (index of multiple deprivation), smoking status, and relevant comorbidities (lung disease, cardiovascular disease, cancer, and depression). NEIAA is supported by people with lived experience of rheumatoid arthritis, who contributed to study design and the interpretation of findings.

Findings: 6098 patients in NEIAA had new diagnoses of rheumatoid arthritis and available follow-up data. The mean age was 59·2 years (SD 14·9); 3912 (64·2%) patients were women and 2186 (35·8%) were men. 6047 (99·2%) patients had available ethnicity data, of whom 5215 (86·2%) were White, 152 (2·5%) were Black, 478 (7·9%) were Asian, and 202 (3·3%) were of mixed or other ethnicities. 508 (8·3%) of 6098 patients initiated biological and targeted synthetic DMARDs within 12 months. Patients younger than 40 years were more likely to be initiated on biological and targeted synthetic DMARDs than individuals older than 65 years (multivariable-adjusted risk ratio 2·41 [95% CI 1·83-3·19]; p<0·0001). Asian individuals were less likely to be initiated on biological and targeted synthetic DMARDs than White individuals (0·52 [0·36-0·76]; p=0·0007), which persisted after adjustment for socioeconomic status, comorbidities, baseline disease severity, and the initial response to conventional synthetic DMARDs. These differences were evident for Asian women but not Asian men. Black individuals were more likely to be initiated on biological and targeted synthetic DMARDs than White individuals (1·54 [1·10-2·16]; p=0·012), which became non-significant after adjusting for baseline disease severity and autoantibody status.

Interpretation: The initiation of biological and targeted synthetic DMARDs for patients with newly diagnosed rheumatoid arthritis varies markedly by ethnicity and age in the universal health-care system of England and Wales. This study demonstrates the importance of providing tailored information and ensuring equitable access to high-quality care for underserved patient groups. The one-size-fits-all approach must be reconsidered if health disparities are to be mitigated effectively.

Funding: Sandoz UK.