Background:
systemic lupus erythematosus (SLE) patients have higher fracture risk, driven by inflammation and glucocorticoids treatment. However, there is limited data on fracture recurrence and post-fracture mortality in this vulnerable population.
Objectives:
We describe the association between SLE and the risk of fracture; 5 and 10-year recurrent fracture and 5-year post-fracture mortality compared to hospital-based controls in Western Australia (WA) from 1980 - 2014.
Methods:
Population-level cohort study of patients (n=2,440, 28,002 person-years) and
population comparators (controls) (n=10,220; 161,392 person-years) identified within the
Western Australia (WA) Rheumatic Disease Epidemiological Registry (WARDER). Patients
18-80 years old (identified by ICD-9-CM: 695.4, 710.0, ICD-10-AM: L93.0, M32.0) were matched (5:1) for age, sex, Aboriginality, and temporality. Follow-up was from index SLE hospitalisation to fracture-related hospitalisation or death. Using longitudinal linked health data, we determined the relative risk of (low impact) fracture, 5 and 10-year recurrent fractures and 5-year post-fracture mortality between patients and controls with multivariate Cox proportional hazards regression models.
Results:
Patients had higher multivariate-adjusted fracture risk (aHR 2.44, 95%CI 2.08, 2.87; P<0.01) regardless of sex, Aboriginality, age group (highest in those <50 years of age) or study period. Patients had higher risk of hand, wrist and forearm fractures (aHR 1.95), vertebral fractures (aHR 5.73), hip fractures (aHR 1.83), and lower limb, ankle and foot fractures (aHR 2.14). Patients had higher risk of 5 (aHR 2.89) and 10-year (aHR 3.00) fracture recurrence. Patients had higher (aHR 1.56, 95%CI 1.16, 2.09; P<0.01) risk of 5-year post-fracture mortality. Mortality was increased in females (aHR 1.45), ≥70 years-old (aHR 1.72) and remained increased post 2000 (aHR 1.57).
Conclusion:
SLE patients have an increased risk of fractures, 5- and 10-year recurrent fractures and 5-year
mortality post-fracture compared to controls from the general population. This study highlights the need for improved primary prevention of osteoporosis in SLE patients.