Less is known about the risk of fracture in people with rheumatoid arthritis aged under 50 than those in older age groups. The study shows that the risk of fracture before age 50 remains significantly higher in those with rheumatoid arthritis than matched controls. This has implications for fracture risk management.
To determine the risk of first and subsequent fracture occurring before age 50 in people diagnosed with rheumatoid arthritis (RA) before age 50.
A retrospective observational cohort study of RA cases with matched controls using data from Clinical Practice Research Datalink (CPRD) of adults ≥ 18 years with diagnosis of RA recorded from 1992 to 2016 in the UK. Patients were followed from index date to the first fracture and subsequent fracture. A total of 36,858 cases were each matched to 3 controls. Incidence rates (IR) and incidence rate ratios (IRR) of first and subsequent fractures were calculated. A multivariate Cox's proportional hazards model was used to calculate the risk of first fracture and of subsequent fracture in the presence of different risk factors.
The IR of first and subsequent fractures at any age is significantly higher in cases than controls for patients with onset of RA at any age. This includes first fractures occurring before age 50 for those diagnosed with RA before this age. In women, the rate of first fracture before age 50 are significantly higher than matched controls (IRR 1.29 CI 1.12-1.49), the IRR for subsequent fracture is higher but not significantly so. For men, the IRRs of first and subsequent fractures below age 50 are also higher but not significantly so. Gender, previous fracture, glucocorticoid prescription, osteoporosis diagnosis, alcohol, smoking, and bisphosphonate prescription have a significant effect on the risk of first fracture at any age for RA patients; all these variables except osteoporosis diagnosis and alcohol have a significant effect on the risk of subsequent fracture and first fractures before age 50.
These results indicate an increased risk of first fracture before age 50 in people with RA diagnosed before this age. It is important that patients with RA of all ages are given timely support from the time of diagnosis to protect their bone health.