Comparative Fracture Risks among US Medicaid Enrollees with and without Systemic Lupus Erythematosus.

OBJECTIVE: Poor bone health is common in SLE patients. We evaluated fracture risks among low-income SLE and lupus nephritis patients compared to those without SLE.

METHODS: We performed a cohort study within Medicaid 2007-2010, among SLE patients and age- and sex-matched non-SLE comparators. SLE was defined by ≥3 ICD-9 codes for SLE; lupus nephritis patients additionally had ≥2 codes for renal disease. The primary outcome was fracture of the pelvis, wrist, hip, or humerus. Demographics, prescriptions, and comorbidities were assessed during the 180-day baseline period. We calculated fracture incidence rates (IR) and 95% confidence intervals (CI) in SLE, lupus nephritis, and non-SLE comparator cohorts, and estimated adjusted hazard ratios (HR) for fractures. Sensitivity analyses evaluated the impact of glucocorticoids and comorbidities. We compared subsets of SLE patients with and without lupus nephritis.

RESULTS: Among 47,709 SLE patients (19.8% with lupus nephritis) matched to 190,836 non-SLE comparators, mean age was 41.4 years and 92.6% were female. Fracture IR was highest among SLE patients with nephritis (4.60/1,000 person-years). SLE patients had two-fold higher fracture risk than matched comparators (HR 2.09 [95% CI 1.85, 2.37]). Lupus nephritis patients had the greatest fracture risks versus matched comparators (HR 3.06 [2.24, 4.17]), and 1.6 times higher risk than SLE patients without nephritis (HR 1.58 [1.20, 2.07]). Adjustment for glucocorticoid use and comorbidities slightly attenuated risks.

CONCLUSION: Fracture risks were elevated in SLE patients, particularly those with lupus nephritis, compared to matched non-SLE Medicaid patients. Elevated risks persisted after adjustment for baseline glucocorticoids and comorbidities. This article is protected by copyright. All rights reserved.