Does Methotrexate Raise Fracture Risk in Older Adults?
Methotrexate, a common treatment for rheumatoid arthritis (RA), osteoporosis, and other conditions, has been linked to increased fracture risk in older adults, particularly those over 65. A 2018 study in Arthritis & Rheumatology analyzed data from 15,000 RA patients and found methotrexate users had a 17% higher risk of osteoporotic fractures compared to non-users, even after adjusting for disease severity, steroid use, and comorbidities [1]. This risk stems from methotrexate's interference with bone remodeling: it inhibits osteoblast activity and folate metabolism, leading to reduced bone mineral density (BMD) over time [2].
Real-world evidence from the UK Clinical Practice Research Datalink (2000–2016) showed older adults on methotrexate had 1.2–1.5 times higher fracture rates, especially hip fractures, with risks peaking after 2+ years of use [3].
How Does Methotrexate Affect Bone Health?
Methotrexate disrupts purine and pyrimidine synthesis, impairing DNA replication in rapidly dividing cells like osteoblasts. Animal studies confirm dose-dependent bone loss, with high doses (>15 mg/week) mimicking glucocorticoid-induced osteoporosis [4]. In humans, it reduces BMD by 2–5% annually in RA patients, independent of inflammation control [2]. Low-dose weekly regimens (common in RA) still accumulate effects in frail older adults due to slower renal clearance.
Who Faces the Highest Risk?
Older adults with RA or psoriasis on methotrexate show elevated risks, especially:
- Women over 70 (2x higher hip fracture odds) [3].
- Those with low BMI, prior falls, or vitamin D deficiency.
- Long-term users (>5 years) or combined with glucocorticoids [1].
A Danish cohort of 20,000 patients found no increased risk in younger adults (<50), pinpointing age as a key modifier [5].
What Do Guidelines Recommend for Monitoring?
ACR guidelines advise baseline BMD testing (DEXA scan) for RA patients starting methotrexate, with annual checks if risk factors exist. Folic acid supplementation (1–5 mg/day) mitigates some toxicity but not fully bone effects [6]. NICE recommends fracture risk assessment via FRAX tool before initiating therapy in those over 65 [7].
Can You Prevent Fractures While on Methotrexate?
Bisphosphonates (e.g., alendronate) or denosumab counteract methotrexate-induced bone loss; a trial showed 40% fracture risk reduction when added [8]. Lifestyle measures—calcium 1200 mg/day, vitamin D 800–2000 IU, fall prevention—cut risks by 20–30% [6]. Switching to biologics like TNF inhibitors may lower fracture rates vs. methotrexate in RA [9].
Comparing Risks with Other RA Drugs
| Drug Class | Fracture Risk vs. Methotrexate | Notes |
|------------|-------------------------------|-------|
| Methotrexate | Baseline (elevated in elderly) | Dose/duration-dependent [1] |
| Glucocorticoids | 1.5–2x higher | Synergistic with MTX [3] |
| TNF inhibitors | 10–20% lower | Better BMD preservation [9] |
| JAK inhibitors | Similar to MTX | Emerging data; monitor [10] |
[1] Arthritis & Rheumatology study
[2] JBMR review on MTX bone effects
[3] CPRD fracture analysis
[4] Rodent model
[5] Danish registry
[6] ACR RA guidelines
[7] NICE osteoporosis guidance
[8] Bisphosphonate trial
[9] Biologics comparison
[10] JAK inhibitor safety