FRACTURES AMONG OLDER KIDNEY TRANSPLANT RECIPIENTS: A STUDY OF THE INCIDENCE OF FRACTURES, RISK FACTORS FOR INCIDENT FRACTURES, AND SUBSEQUENT MORTALITY
Embargo until
Date
2017-04-19
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Johns Hopkins University
Abstract
BACKGROUND: Adult kidney transplant (KT) recipients are at greater risk of fractures than the general population, however, the burden of fractures has not been well studied in older KT recipients. Age plays a strong role in the risk of fractures and sequelae among older populations, in general. Therefore, the goals of this study were to identify the incidence of fractures, risk factors for fractures, and rates of subsequent outcomes in older KT recipients. We also tested whether epidemiology of fractures differs for older-old (defined in this paper as 55-64 years old) and younger-old (defined in this paper as ≥65 years old) age subgroups.
METHODS: 38,382 older (≥ 55 years) adult KT recipients who had Medicare primary coverage were identified through the USRDS registry. We estimated the cumulative incidence of post-KT fractures by age, sex, race, BMI and history of diabetes, in younger-old (55-64 years) and older-old (≥65 years) KT recipients. We identified risk factors of post-KT fractures for older
recipients using a Fine and Gray competing risk approach, accounting for the competing events of mortality and DCGL, and tested whether age modified the associations of sex, race, BMI and year of KT with post-KT fractures. We then tested whether post-KT fracture was a risk factor for subsequent mortality and DCGL using adjusted Cox proportional hazards models, and tested whether age, sex, race, BMI and year of KT modified the associations of post-KT fractures with morality and DCGL.
RESULTS: The cumulative incidence of postKT fractures increased with age. The risk factors of post-KT fractures included recipient (age, sex, race, BMI, history of diabetes, time on dialysis, and peak PRA), transplant (year of KT, number of HLA mismatches), and donor factors (living donor, standard deceased donor, expanded criteria donor, and donation after cardiac death). In the younger-old group, diabetes (HR=2.35, 95% CI: 2.06-2.69) and White race (White vs. African American: HR=2.28, 95% CI: 1.92-2.69) were the two strongest risk factors; in the older-old group, underweight (HR=2.06, 95% CI: 1.29-3.28) and White race (White vs. African American: HR=2.11, 95% CI: 1.74-2.56) were the two strongest risk factors. Age (younger-old vs. older-old) modified the association between diabetes and post-KT fracture (younger-old: HR=2.35, 95% CI: 2.06-2.69, older-old: HR=1.74, 95% CI: 1.53-1.97, P for interaction=0.001). PostKT fractures were associated with a 2-fold increase in subsequent mortality (HR=2.09, 95% CI: 1.94-2.25) and a 1.9-fold increase in subsequent DCGL (HR=1.87, 95% CI: 1.75-2.00) in the older KT recipients. White race and diabetes modified the associations of post-KT fractures with mortality (White: HR=2.20, 95% CI: 2.01-2.41, non-White: HR=1.85, 95% CI: 1.62-2.11, P for interaction=0.03; diabetes: HR=1.93, 95% CI: 1.75-2.13, non-diabetes: HR=2.35, 95% CI: 2.10-2.63, P for interaction=0.008) and DCGL (White: HR=2.01, 95% CI: 1.85-2.18, non-White: HR=1.60, 95% CI: 1.43-1.78, P for interaction=0.001; diabetes: HR=1.76, 95% CI: 1.62-1.92, non-diabetes: HR=2.04, 95% CI: 1.85-2.25, P for interaction=0.03).
CONCLUSION: Older-old KT recipients had a higher risk of developing post-KT fractures. Recipients, transplant, and donor factors were associated with post-KT fractures. Older KT recipients who had post-KT fractures were at increased risk of both subsequent death and graft loss.
Advisor: Mara A. McAdams-DeMarco
Reader: Allan B. Massie
Description
Keywords
Kidney Transplant, Incident Fractures, Aging Recipients