Exploring temporal trends in the incidence and prevalence of rheumatoid arthritis, and venous thromboembolism risk factors in women with rheumatoid arthritis in England

Study type
Protocol
Date of Approval
Study reference ID
23_003680
Lay Summary

Rheumatoid arthritis (RA) is a chronic condition characterised by joint swelling, damage, and associated health issues that can cause pain, affect mobility, and impair overall quality of life. Importantly, the number of people being diagnosed with RA is increasing worldwide.

People with RA also have a higher chance of getting dangerous blood clots. Understanding more about this risk for women with RA, particularly in those who are taking hormone-based medications that can exacerbate the risk, is essential for effectively managing these patients and enhancing their well-being and life expectancy.

This project has two main parts: the first one is an analysis of how common RA is among English adults, looking at different population groups based on age, sex, ethnic background, geography and socioeconomic status. We will also see how the number of people getting RA has changed over the last twenty years, and estimate how it might change in the future. Additionally, we will examine data from hospitals to determine if the number of people with RA differs from what we observe in GP records.

The second part of the project involves examining the likelihood of blood clots in women with RA who are undergoing hormone treatments, with a particular emphasis on those of child-bearing age or experiencing menopause.

The study will have clear patient benefit by providing information to support health professionals identify who is most at risk of developing RA, and by informing future risk management strategies for women with RA taking hormone-based medications.

Technical Summary

RA is a chronic inflammatory condition causing joint inflammation, damage, and additional complications, lowering functionality and quality of life. RA patients face an increased risk of venous thromboembolism (VTE), further worsening their well-being. This retrospective study of adults in England, utilising data from Clinical Practice Research Datalink (CPRD) Aurum, has two main components: assessing the impact of ethnicity, geography, and socioeconomic status (SES) on RA incidence and prevalence; and comparing VTE risk among female RA patients of different ages with or without hormonal treatments.

People with RA will be identified from primary care records using a case definition based on the work of Scott et al [1]. Overall incidence rates and rates stratified by sociodemographic subgroups (sex, ethnicity, SES and geographic region) will be computed, as will the point prevalence at the end of the 20-year study period to provide a contemporary estimate. Annual incidence and prevalence of RA will be estimated over the 20-year study period, overall and stratified by the same sociodemographic subgroups noted above. Poisson regression (for incidence) and logistic regression (for prevalence) will be used to assess the significance of temporal trends over time, overall and by the same sociodemographic subgroups. Age-period-cohort modelling will be used to project RA incidence rates and prevalence up to 2035 [2, 3]. Additionally, sensitivity analysis will be performed comparing results based solely on primary care data to a broader case definition of RA.

For the assessment of VTE risk in women with RA, incidence will be stratified by the use of oral contraception or HRT. Cumulative incidence curves will be used to illustrate time to VTE development. The risk of VTE will be evaluated in a mixed cohort of prevalent and incident RA cases matched with unaffected controls, using Cox proportional hazards models unadjusted or adjusted for confounders.

Health Outcomes to be Measured

Primary outcomes:
- Incident RA
- Outcomes comprising: VTE (composite of PE or VTE), deep vein thrombosis (DVT) and pulmonary embolism (PE).

Secondary outcome:
- Mortality: (1) all-cause, and (2) for VTE-related reasons.

Collaborators

Michael McLean - Chief Investigator - Pfizer Ltd - UK
Emma Jones - Corresponding Applicant - Momentum Data Ltd
Andrew McGovern - Collaborator - Momentum Data Ltd
Anita Lynam - Collaborator - Momentum Data Ltd
Eva Henning - Collaborator - Pfizer Ltd - UK
Gulraj Matharu - Collaborator - Pfizer Ltd - UK
Maciej Czachorowski - Collaborator - Pfizer Ltd - UK
Mary Araghi ( Gerino ) - Collaborator - Pfizer Ltd - UK
Muhammad (Ashkan) Dashtban - Collaborator - Momentum Data Ltd
Saqib Rana - Collaborator - Pfizer Ltd - UK
Serhan Bahit - Collaborator - Momentum Data Ltd

Linkages

HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation