Increased risk of hip and major osteoporotic fractures in 8463 patients who have undergone stem cell transplantation, a Swedish population-based study

Abstract

Summary: In this retrospective cohort study of adult stem cell transplanted patients (n = 8463), a significant increased risk of both MOF and hip fractures was seen compared with the Swedish population and occurred in mean more than 2 years after stem cell transplantation. Purpose: To explore the risk for osteoporotic fracture in patients who have undergone hematopoietic stem cell transplantation (HSCT) compared with the Swedish population. Methods: The risk of osteoporotic fractures was determined in a retrospective population cohort study of adult (≥ 18 years) Swedish patients (n = 8463), who were transplanted with HSCT 1997–2016 and compared with all adults living in Sweden during the same period. Results: In the total study group (n = 8463), 90 hip fractures (1.1% both in males and females) and 361 major osteoporotic fractures (MOF) (3.2% in men and 6.0% in women) were identified. In the total study population, the ratio of observed and expected number of hip fracture for women was 1.99 (95% CI 1.39–2.75) and for men 2.54 (95% CI 1.91–3.31). The corresponding ratio for MOF in women was 1.36 (CI 1.18–1.56) and for men 1.61 (CI 1.37–1.88). From 2005 onwards, when differentiation in the registry between allo- and auto-HSCT was possible, the observed number of hip fracture and MOF in allo-HSCT (n = 1865) were significantly increased (observed/expected hip fracture 5.24 (95% CI 3.28–7.93) and observed/expected MOF 2.08 (95% CI 1.63–2.62)). Fractures occurred in mean 2.7 (hip) and 2.5 (MOF) years after allo-HSCT. Graft-versus-host disease (GVHD) was not associated with an increased risk of fracture. Conclusion: Patients who underwent HSCT had an increased risk of both hip and major osteoporotic fracture compared with the Swedish population and occurred in 4.3% of patients. GVHD was not statistically significantly associated with fracture risk.