Older donor age and end-stage renal disease (ESRD) caused by diabetes or cystic kidney disease are among the risk factors for major bone fractures in kidney transplant recipients, according to a recent paper published in the World Journal of Transplantation (2016;6:370-379).
Kyla L. Naylor, MD, of the Institute for Clinical Evaluative Sciences in London, Ontario, Canada, and colleagues studied 2723 adults who received kidney-only transplants from 2002 to 2009. They examined general risk factors (such as age, sex, and prior major fracture) and transplant-specific risk factors (such as donor age and cause of ESRD) for major fractures.
Major fractures included those of the proximal humerus, forearm, and hip, as well as clinical vertebral fractures.
During an average follow-up of 6 years, 132 patients (4.8%) suffered a major fracture (8.1 fractures per 1000 person-years) and 402 patients died (14.8%).
Compared with recipients who did not suffer a major fracture, those who did were significantly older (median age 56.5 vs. 50.5 years), were more likely to be women (48.5% vs. 35.8%), and were less likely to have glomerulonephritis as their cause of ESRD (29.6% vs. 36.7%).
In multivariable analysis, each 5-year increment in recipient age was associated with a significant 11% increased risk of major fracture. Women had an 81% increased risk of major fracture compared with men. Compared with recipients whose ESRD was caused by glomerulonephritis, those with ESRD caused by diabetes or cystic kidney disease had a 72% and 73% increased risk of major fracture, respectively. Each 5-year increment in donor age was associated with a 9% increased risk.
The investigators also assessed risk factors for fractures in other locations (excluding major fractures and fractures of the skull, hands, or feet). Diabetes and a fall with hospitalization in the year prior to transplantation were the general risk factors associated with an greater risk of these other fractures, and length of time on dialysis and renal vascular disease and other causes of ESRD were the transplant-specific risk factors associated with a greater risk of other fractures. The researchers found no association between recipient age and female sex and the risk of other fractures.
“Our findings suggest that both general and transplant-specific risk factors for fracture should be considered by clinicians when assessing fracture risk in kidney transplant recipients,” Dr Naylor’s team wrote. “However, different risk factors may need to be taken into account when considering different fracture locations.”
The investigators commented that, unfortunately, “none of the risk factors for major fractures found in this study are easily modifiable.”