OBJECTIVE: It is unknown whether patients affected by granulomatosis with polyangiitis (GPA) are at increased risk of fractures, and whether the fracture risk in GPA varies with age and sex. The aim of the present study was to compare the fracture risk among patients with GPA with that among age- and sex-matched population controls.
METHODS: We established a monocentric cohort of patients treated for GPA at a Danish tertiary care center from 1995 to 2010 (n = 159) and a register-derived GPA cohort identified from the Danish National Hospital Register (n = 402). Each patient was matched with 7 population controls. The occurrence of fractures among patients was compared with that among controls by calculation of incidence rate ratios (IRR).
RESULTS: In the monocentric cohort, an increased fracture risk was observed among men aged ≥ 55 years at the time of first hospitalization for GPA (IRR 3.5, 95% CI 1.6-7.6), but not among men < 55 years (IRR 0.3, 95% CI 0.04-2.1) or women (IRR women ≥ 55 yrs: 1.0, 95% CI 0.4-2.7 and IRR for women < 55 yrs: 0.7, 95% CI 0.2-2.4). In the register-derived cohort, an increased fracture risk was also observed among men aged ≥ 55 years at study baseline (IRR 2.0, 95% CI 1.2-3.5), whereas the incidence rate of fractures was not significantly increased among younger men or women (IRR for men < 55 yrs: 1.0, 95% CI 0.4-2.3; IRR for women ≥ 55 yrs: 0.9, 95% CI 0.5-1.5; IRR for women < 55 yrs: 1.6, 95% CI 0.7-3.6).
CONCLUSION: Elderly male patients with GPA have a pronounced risk of developing fractures. This finding is of relevance for the clinical management of patients with GPA.