HSCT associated with increased risk for fractures
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Patients who underwent hematopoietic stem cell transplantation had a considerably higher incidence of fractures compared with the general population, according to results of a retrospective analysis.
With the increased use of HSCT in the treatment of cancers and benign hematologic conditions, and associatively an increase in the number of long-term survivors, more late complications for these patients have been identified. A loss of bone mineral density after HSCT may predispose patients to future bone loss and an increased rate of fracture and osteoporosis, according to study background.
“Fractures are a concern in the survivorship period following HSCT and affect both morbidity and mortality,” Huifang Lu, MD, PhD, of the department of general internal medicine at The University of Texas MD Anderson Cancer Center, told HemOnc Today. “Prevention of bone loss and consequent fractures is imperative, especially since reversal of bone loss is a complex process and prevention of bone loss can potentially have tremendous clinical impact.”
Lu and colleagues conducted a single-institution study to evaluate fracture incidence and its risk factors among patients who underwent HSCT. Researchers compared these fracture rates with those of individuals in the general population using the data from the 1994 National Health Interview Survey and the 2004 National Hospital Discharge Survey.
The analysis included 7,620 patients who underwent HSCT between 1997 and 2011. Fifty-six percent of the adults were men and 75% were white.
Median follow-up was 7.08 years.
Overall, 8% of the cohort developed a fracture.
Data indicated age and sex-specific fracture incidence rates were greater in patients who underwent HSCT than in the general U.S. population. The risk for facture increased eightfold among women and seven to nine times among men aged 45 to 64 years who underwent HSCT compared with the general population.
Because of a high correlation between indication for HSCT and the type of HSCT received, the investigators analyzed their effects using multivariable models.
One model included all predictors except the HSCT type, whereas the other included all the predictors except the indication for the HSCT procedure. In both cases, fracture incidence was greater in patients aged older than vs. younger than 50 years.
Fracture risk also was increased approximately five times among patients with multiple myeloma and 1.6 times among patients with solid organ and other tumors vs. other hematologic malignancies. Further, patients who underwent autologous HSCT were 45% more likely to develop a fracture than those who underwent allogenic HSCT.
Most of the fractures (53%) were considered vertebral. The most common nonvertebral fractures were clavicle/ribs (18%), upper limb (10%), femur (7%) lower limb other than femoral (7%) and hip (3%). Men had more vertebral fractures (57%), whereas women had more nonvertebral fractures (53%; P = .013).
The researchers added that the incidence rate of fractures after HSCT could be even more disparate from the general population because some patients in the cohort may have had their fractures treated at a location other than MD Anderson Cancer Center. They also noted that 53% of the original cohort died before experiencing a fracture, but a competing risk analysis that accounted for death did not skew the data.
“Several uncertainties remain with respect to the optimal timing for screening, initiation of treatment and dosing regimens,” Lu said. “Based on results from our study, we recommend patients older than 50 years at the time of transplant and undergoing autologous transplantation be monitored closely.”
Lu added that all patients undergoing HSCT should be considered at risk and, therefore, general preventive measures such as calcium and vitamin D supplementation, as well as counseling on the benefits of exercise, smoking cessation and moderation of alcohol consumption, should be started early.
“It is postulated that bone loss following HSCT is a multifactorial process depending on the underlying malignancy, type of transplant and supportive treatment, as well as other comorbid conditions and genetic factors,” Lu said. “Our research team is focusing to address these questions and to explore the mechanisms involved in increased bone loss and fractures following HSCT.” – by Anthony SanFilippo
For more information:
Huifang Lu, MD, PhD, can be reached at The University of Texas MD Anderson Cancer Center
1515 Holcombe Blvd., Houston, TX 77030; email: hlu@mdanderson.org
Disclosure: Lu reports no relevant financial disclosures. One researcher reports consultant/advisory roles with Actinium, AiCuris, Alexion, Amgen, Celgene and Takeda.