Osteoporosis, commonly known as brittle bones, and osteoporotic (OP) fractures are major complications among patients with rheumatoid arthritis (RA), which could bring about a lot of ailments for the affected patient. The background inflammation of the disease, and the drug treatment that patients with RA receive are some factors that contribute to this increased risk of OP fractures in this group of patients.
Glucocorticoids (GC) are probably the most important drugs with a role in osteoporosis that are routinely prescribed in patients with RA. Previous studies showed that taking GC, especially in low-doses, might also benefit these patients respecting bone health, by suppressing the background inflammation of the disease and improving the mobility of patients. Indeed, many studies have shown this positive effect on bone mineral density (BMD).
But to date, there are few studies who considered the effect of low-dose GC on fracture risk in patients with RA and their results are conflicting, and mostly in contrast to BMD studies mentioned above. Thus, the aim of this study is to investigate use of low-dose GC on OP fracture risk among patients with RA in the UK.
Objectives: To investigate the effect of low-dose oral glucocorticoids (GC) on the osteoporotic fracture risk among patients with rheumatoid arthritis (RA).
Design: Retrospective cohort study using the Clinical Practice Research Datalink (CPRD) GOLD.
Participants: All adults aged 50 years and older diagnosed with RA in CPRD between 1997 and 2017. The index date will be the RA diagnosis, recorded as the first read code for RA during valid data collection.
Primary exposure: The primary exposures of interest is the use of low-dose oral GC in RA patients, defined as an average daily dose ?7.5mg/d. Exposure to treatment will be assessed in a time-varying way and in 30-day follow-up periods.
Outcome: The outcome in our study is occurrence of the first incident osteoporotic (OP) fracture in RA patients after the index date, which include hip, clinically symptomatic vertebral, humerus, forearm, pelvic, and rib fractures.
Statistical analyses: Cox proportional-hazards models will be used to conduct the statistical analysis. The first and main analysis will compare the OP fracture risk between RA patients who are current users of low-dose GC, and RA patients who stopped taking GC for longer than 1 year (past users). Separate analyses will be conducted for various OP fracture sites. The secondary analysis will focus on a combination of average daily and cumulative dose of current GC use in RA patients and will be compared to past-use. All calculations will be adjusted for the potential confounders.
Occurrence of an osteoporotic fracture, including hip, clinically symptomatic vertebral, humerus, forearm, pelvic, and rib fractures.
Patrick Souverein - Chief Investigator - Utrecht University
Patrick Souverein - Corresponding Applicant - Utrecht University
Andrea Burden - Collaborator - ETH Zurich
Anna Elise (Annelies) Boonen - Collaborator - Maastricht University Medical Centre
Frank de Vries - Collaborator - Utrecht University
Johanna Driessen - Collaborator - Utrecht University
Joop van den Bergh - Collaborator - Maastricht University
Shahab Abtahi - Collaborator - Utrecht University
Tjeerd van Staa - Collaborator - University of Manchester
Frank de Vries - Chief Investigator - Utrecht University