Background Bone loss and fractures following hematopoietic stem cell transplantation (HSCT) is common,(1, 2) and identifying patients at high risk for osteoporotic fractures following HSCT remains challenging. In the general population, the World Health Organization fracture risk assessment tool - FRAX is utilized to estimate a patient's 10-year probability of developing a major osteoporotic fracture and hip fracture.(3) However, the utility of the FRAX model in predicting fractures following HSCT has not been evaluated.

Objectives To assess the predictive value of FRAX in osteoporotic fracture risk assessment following HSCT.

Methods We conducted a retrospective cohort study of patients >18 years that received a HSCT at The University of Texas MD Anderson Cancer Center, from January 1, 2001 to December 31, 2010. Patients were considered to have entered the cohort at the time of HSCT. All patients were retrospectively followed until December 31, 2013 for assessment of osteoporotic fracture. Osteoporotic fractures following HSCT were identified using ICD-9 codes, and confirmed by radiology and physician documentation. FRAX probabilities were calculated from baseline information obtained by chart review.

Results A total of 5,170 patients underwent a HSCT during the 10-year study period. During an average of 3.3 years of follow up, 10% of patients developed a fracture. Fracture rates were higher (14%) in patients that underwent an autologous HSCT in comparison to those that received an allogeneic HSCT (6%). Mean major osteoporotic fracture FRAX scores were significantly higher in individuals who sustained an osteoporotic fracture compared to individuals who did not. The area under the receiver operating characteristic curve at 5 and 10 years following the HSCT were 0.61 and 0.66 respectively (Figure). We assessed the ability of the FRAX model for prediction of osteoporotic fracture with and without considering death as a competing risk. The hazard ratios were similar for both models (HR, 2.63, 95% CI, 1.93, 3.59; HR, 2.54, 95% CI, 1.86, 3.47, respectively).

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Figure 1

Conclusions To the best of our knowledge, this is the first study to demonstrate that the FRAX model has modest discriminative ability in predicting osteoporotic fractures following HSCT. Further independent validation of our findings is necessary, before routinely using the FRAX model in clinical practice.

References

1. Pundole XN, Barbo AG, Lin H, Champlin RE, Lu H. Increased incidence of fractures in recipients of hematopoietic stem-cell transplantation. Journal of clinical oncology: official journal of the American Society of Clinical Oncology. 2015;33(12):1364–70.

2. Schimmer AD, Minden MD, Keating A. Osteoporosis after blood and marrow transplantation: clinical aspects. Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation. 2000;6(2A):175–81.

3. Kanis JA, Johnell O, Oden A, Johansson H, McCloskey E. FRAX and the assessment of fracture probability in men and women from the UK. Osteoporosis international: a journal established as result of cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA. 2008;19(4):385–97.

References

Disclosure of Interest None declared