Elevated risk of clinical fractures and associated risk factors in patients with systemic lupus erythematosus versus matched controls: A population-based study in the United Kingdom
Bultink IEM., Harvey NC., Lalmohamed A., Cooper C., Lems WF., Van Staa TP., De Vries F.
Summary: The incidence of clinical fractures and the associated factors were assessed in patients with systemic lupus erythematosus (SLE) versus matched controls. We found an increased fracture risk in SLE patients compared to controls. Glucocorticoid use, longer disease duration, neuropsychiatric disease complications and previous osteoporotic fractures were identified as associated factors. Introduction: The aims of this study were to estimate the risk of clinical fractures in patients with SLE versus matched controls and to evaluate the risk factors associated with clinical fractures in SLE. Methods: This is a population-based cohort study using the Clinical Practice Research Datalink (from 1987-2012). Each SLE patient (n=4,343) was matched with up to six controls (n=21,780) by age and sex. Clinical fracture type was stratified according to the WHO definitions into osteoporotic and non-osteoporotic fracture. Cox proportional hazards calculated relative rates (RR) of clinical fracture and time interaction terms to evaluate the timing patterns of fracture. Clinical fracture rates in SLE patients, stratified by age, gender, type of fracture, disease duration and therapy variables, were compared with those rates in controls. Results: Follow-up durations were 6.4 years in SLE patients and 6.6 years in controls. SLE patients had a 1.2-fold increased clinical fracture risk compared to controls (adjusted RR=1.22, 95% CI=1.05-1.42), and the risk further increased with a longer disease duration. Glucocorticoid (GC) use in the previous 6 months raised the risk of clinical fracture (adjusted RR=1.27, 95% CI=1.02-1.58). Cerebrovascular events, seizures and previous osteoporotic fractures were identified as predictors of clinical fractures. Conclusions: We found an increased risk of clinical fracture in SLE patients compared to controls. GC use in the previous 6 months and longer disease duration are associated with the increased fracture risk in SLE. Patients with neuropsychiatric organ damage or previous osteoporotic fractures are also at increased risk of the occurrence of clinical fractures. © 2013 International Osteoporosis Foundation and National Osteoporosis Foundation.