Childhood onset arthritis is associated with an increased risk of fracture: a population based study using the General Practice Research Database
- 1Department of Pediatrics, Division of Rheumatology, Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, USA
- 2Department of Nephrology, Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, USA
- 3Department of Medicine, Division of Gastroenterology, Hospital of the University of Pennsylvania, University of Pennsylvania School of Medicine, USA
- 4Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, USA
- Correspondence to:
Dr J M Burnham
Room 1579 CHOP North, 3535 Market Street, Philadelphia, PA 19104, USA;
- Accepted 5 March 2006
- Published Online First 20 April 2006
Background: Childhood onset arthritis is associated with low bone mass and strength.
Objective: To determine whether childhood onset arthritis is associated with greater fracture risk.
Methods: In a retrospective cohort study all subjects with onset of arthritis between 1 and 19 years of age in the United Kingdom General Practice Research Database were identified. As controls, all sex and age matched subjects from a practice that included a subject with arthritis were included. Incidence rate ratios (IRRs) for first fracture were generated using Mantel-Haenszel methods and Poisson regression.
Results: 1939 subjects with arthritis (51% female) and 207 072 controls (53% female) were identified. The median age at arthritis diagnosis was 10.9 years. A total of 129 (6.7%) first fractures were noted in subjects with arthritis compared with 6910 (3.3%) in controls over a median follow up of 3.90 and 3.95 years in the subjects with arthritis and controls, respectively. The IRR (95% confidence interval) for first fracture among subjects with arthritis, compared with controls, according to the age at the start of follow up were 1.49 (0.91 to 2.31) for age <10 years, 3.13 (2.21 to 4.33) at 10–15 years, 1.75 (1.18 to 2.51) at 15–20 years, 1.40 (0.91 to 2.08) at 20–45 years, and 3.97 (2.23 to 6.59) at >45 years.
Conclusions: Childhood onset arthritis is associated with a clinically significant increased risk of fracture in children, adolescents and, possibly, adults. Studies are urgently needed to characterise the determinants of structural bone abnormalities in childhood arthritis and devise prevention and treatment strategies.
- CI, confidence interval
- DMARDs, disease modifying antirheumatic drugs
- DXA, dual x ray absorptiometry
- GPRD, General Practice Research Database
- IRR, incidence rate ratio
- JIA, juvenile idiopathic arthritis
- NSAIDs, non-steroidal anti-inflammatory drugs
- OXMIS, Oxford Medical Information Systems
- pQCT, peripheral quantitative computed tomography
- RA, rheumatoid arthritis
- UTS, up to standard
Competing interest: Dr Lewis receives research support from Johnson & Johnson, GlaxoSmithKline, and Takeda Pharmaceuticals North America. He also serves as a consultant for Wyeth Pharmaceuticals, Merck & Co, Elan Pharmaceuticals, Synta Pharmaceuticals, Palatin Technologies, and Berlex. None of the other authors have any conflict of interest.