Objectives To assess whether prodromal symptoms of rheumatoid arthritis (RA), as recorded in the Clinical Practice Research Datalink Aurum (CPRD) database of English primary care records, differ by ethnicity and socioeconomic status.

Methods A cross-sectional study to determine the coding of common symptoms (≥0.1 % in the sample) in the 24 months preceding RA diagnosis in CPRD Aurum, recorded between January 1st 2004 to May 1st 2022. Eligible cases were adults with a code for RA diagnosis. For each symptom, a logistic regression was performed with the symptom as dependent variable, and ethnicity and socioeconomic status as independent variables. Results were adjusted for sex, age, BMI, and smoking status. White ethnicity and the highest socioeconomic quintile were comparators.

Results In total, 70115 cases were eligible for inclusion, of which 66.4 % female. Twenty-one symptoms were coded in more than 0.1 % of cases so were included in the analysis. Patients of South Asian ethnicity had higher frequency of codes for several symptoms, with the largest difference by odds ratio being muscle cramps (OR 1.71, 1.44-2.57) and shoulder pain (1.44, 1.25-1.66). Patients of Black ethnicity had higher prevalence of several codes including unintended weight loss (2.02, 1.25-3.28) and ankle pain (1.51, 1.02-2.23). Low socioeconomic status was associated with morning stiffness (1.74, 1.08-2.80) and falls (1.37, 2.03-1.82)

Conclusion There are significant differences in coded symptoms between demographic groups, which must be considered in clinical practice in diverse populations and to avoid algorithmic bias in prediction tools derived from routinely collected healthcare data.

Key messages

- There are differences in symptom reporting in new onset rheumatoid arthritis across ethnic groups.

- These differences should be considered in clinical practice in diverse populations.

- The findings are relevant in avoiding bias in prediction tools derived from healthcare data.

The authors have declared no competing interest.

AD is funded by a PhD studentship from the Applied Research Collaboration Northwest, in turn funded by the National Institute for Health Research (NIHR). NIHR Research for Patient Benefit fund the Development and validation of Rheumatoid Arthritis PredIction moDel using primary care health records (RAPID), which this study was conducted as part of, grant NIHR203621. BH is funded by a MB-PhD studentship from the Kennedy Trust for Rheumatology Research. KR, KN and NJA are supported by the NIHR Birmingham Biomedical Research Centre (BRC). This is independent research carried out at the NIHR BRC. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

This study and the use of Clinical Practice Research Datalink (CPRD) Aurum and linked IMD data was approved by the CPRD Research Data Governance board, reference number 22_002367. The study was conducted in accordance with the recommendations for physicians involved in research on human subjects adopted by the 18th World Medical Assembly, Helsinki 1964, and later revisions.

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