Inflammatory arthritis includes several different conditions causing inflamed joints. The commonest types are “rheumatoid arthritis”, “psoriatic arthritis”, and “axial spondyloarthritis”. It is common, affecting 1 in 100 people.
Despite the availability of effective medicines to control inflammation, many patients with inflammatory arthritis suffer daily pain, which has a major impact on their lives. Consequently, pain medicines are widely prescribed, with around 1 in 10 patients with inflammatory arthritis receiving a medicine called a "gabapentinoid" in England in 2020. Whilst gabapentinoids have been shown to help a specific type of pain from nerve damage, no studies exist that show they help pain in patients with inflammatory arthritis.
Of further concern is that some studies suggest gabapentinoids may increase the risk of people suffering breaks in their bones (called "fractures"), although their findings are not conclusive. This is worrying for patients with inflammatory arthritis who are already more likely to suffer from fractures than other people.
Our study will investigate if gabapentinoids increase the risk of fractures in patients with inflammatory arthritis, providing much needed information on the harms of these medicines in people with these conditions. It forms part of a larger programme of work, and its findings will be considered alongside the results of other studies outside of the CPRD (examining how often people with inflammatory arthritis use pain medicines, the non-drug pain treatments they receive, and the risks/benefits of pain treatments) to develop recommendations about the best way to treat pain in people with inflammatory arthritis.
BACKGROUND
Inflammatory arthritis (IA) groups diseases involving immune-driven joint inflammation. Its three main forms – rheumatoid arthritis (RA), psoriatic arthritis (PsA), and axial spondyloarthritis (SpA) – affect >1% of adults in England.
Chronic pain is a major problem for patients with IA. Consequently, gabapentinoids are often prescribed despite an absence of trials demonstrating efficacy. Of particular concern is that some observational studies suggest gabapentinoids may increase the risk of fractures, which is a common comorbidity in patients with IA. Overall, however, existing evidence on this topic is inconclusive with further research required to better establish the relationship between gabapentinoids and fractures.
AIM
To evaluate the risk of fractures associated with gabapentinoid use in patients with IA.
OBJECTIVES
To undertake the following in patients with diagnoses of RA, PsA, and axial SpA using data from CPRD Aurum:
1. Determine the risk of fractures in patients currently and recently receiving a gabapentinoid prescription, compared to those receiving a prescription in the remote past.
2. Examine if this risk differs by the type and dose of gabapentinoid treatment, alongside the duration of current therapy.
3. Evaluate if this risk is higher in older than younger patients.
METHODS
A nested case-control study will be performed. Conditional logistic regression models will compare the odds of current or recent gabapentinoid use relative to remote gabapentinoid use in cases with an incident fracture post-IA diagnosis and age, gender, and gabapentin-type matched controls without fractures.
Fracture.
Ian Scott - Chief Investigator - Keele University
Ian Scott - Corresponding Applicant - Keele University
Christian Mallen - Collaborator - Keele University
Helen Twohig - Collaborator - Keele University
James Bailey - Collaborator - Keele University
Kelvin Jordan - Collaborator - Keele University
Khadijah Daud - Collaborator - Keele University
Samantha Hider - Collaborator - Keele University
Sara Muller - Collaborator - Keele University
HES Admitted Patient Care