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©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Jun 24, 2016; 6(2): 370-379
Published online Jun 24, 2016. doi: 10.5500/wjt.v6.i2.370
Risk factors for fracture in adult kidney transplant recipients
Kyla L Naylor, Guangyong Zou, William D Leslie, Anthony B Hodsman, Ngan N Lam, Eric McArthur, Lisa-Ann Fraser, Gregory A Knoll, Jonathan D Adachi, S Joseph Kim, Amit X Garg
Kyla L Naylor, Eric McArthur, Amit X Garg, Institute for Clinical Evaluative Sciences, London, ON N6A 4G5, Canada
Kyla L Naylor, 2nd Institute of Health Policy, Management and Evaluation, University of Toronto, ON M5T 3M6, Canada
Guangyong Zou, Amit X Garg, Department of Epidemiology and Biostatistics, Western University, London, ON N6A 5C1, Canada
William D Leslie, Department of Medicine, University of Manitoba, Winnipeg, MB R2H 2A6, Canada
Anthony B Hodsman, Amit X Garg, Division of Nephrology, Western University, ON N6A 5W9, Canada
Ngan N Lam, Division of Nephrology, University of Alberta, Edmonton, AB T6G 2G3, Canada
Lisa-Ann Fraser, Division of Endocrinology, Western University, ON N6A 5A5, Canada
Gregory A Knoll, Division of Nephrology, Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON K1H 7W9, Canada
Jonathan D Adachi, Division of Rheumatology, McMaster University, Hamilton, ON L8S 4K1, Canada
S Joseph Kim, Division of Nephrology, University Health Network, University of Toronto, Toronto, ON M5G 2C4, Canada
Author contributions: All authors contributed to revising the manuscript.
Institutional review board statement: This study was approved by the institutional review board at Sunnybrook Health Sciences Centre, Toronto, Canada.
Informed consent statement: Data was obtained from data holdings at the Institute for Clinical Evaluative Sciences (ICES). ICES is named as a prescribed entity in Ontario’s privacy law Personal Health Information Protection Act. Prescribed entity status means that health information custodians of all types can legally disclose personal health information to ICES without informed consent for purposes of analysis, evaluation and compiling statistical information about our health care system.
Conflict-of-interest statement: William Leslie: Speaker bureau: Amgen, Eli Lilly, Novartis. Research grants: Amgen, Genzyme. Jonathan Adachi: Speaker/Consultant: Amgen, Eli Lilly, Merck, Novartis, Warner Chilcott. Clinical Trials: Amgen, Eli Lilly, Merck, Novartis. Greg Knoll has received investigator-initiated research grants from Astellas, Pfizer, Roche and Novartis. Amit Garg received an investigator-initiated grant from Astellas and Roche for a Canadian Institutes of Health Research study in living kidney donors. The other authors declare that they have no competing interests.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Kyla L Naylor, Institute for Clinical Evaluative Sciences, Room ELL-111, Westminster, London Health Sciences Centre, 800 Commissioners Road East, London, ON N6A 4G5, Canada. kyla.naylor@ices.on.ca
Telephone: +1-519-6858500 Fax: +1-519-6858269
Received: January 19, 2016
Peer-review started: January 20, 2016
First decision: March 24, 2016
Revised: April 7, 2016
Accepted: June 1, 2016
Article in press: June 3, 2016
Published online: June 24, 2016
AIM: To determine the general and transplant-specific risk factors for fractures in kidney transplant recipients.
METHODS: We conducted a cohort study of all adults who received a kidney-only transplant (n = 2723) in Ontario, Canada between 2002 and 2009. We used multivariable Cox proportional hazards regression to determine general and transplant-specific risk factors for major fractures (proximal humerus, forearm, hip, and clinical vertebral). The final model was established using the backward elimination strategy, selecting risk factors with a P-value ≤ 0.2 and forcing recipient age and sex into the model. We also assessed risk factors for other fracture locations (excluding major fractures, and fractures involving the skull, hands or feet).
RESULTS: There were 132 major fractures in the follow-up (8.1 fractures per 1000 person-years). General risk factors associated with a greater risk of major fracture were older recipient age [adjusted hazard ratio (aHR) per 5-year increase 1.11, 95%CI: 1.03-1.19] and female sex (aHR = 1.81, 95%CI: 1.28-2.57). Transplant-specific risk factors associated with a greater risk of fracture included older donor age (5-year increase) (aHR = 1.09, 95%CI: 1.02-1.17) and end-stage renal disease (ESRD) caused by diabetes (aHR = 1.72, 95%CI: 1.09-2.72) or cystic kidney disease (aHR = 1.73, 95%CI: 1.08-2.78) (compared to glomerulonephritis as the reference cause). Risk factors across the two fracture locations were not consistent (major fracture locations vs other). Specifically, general risk factors associated with an increased risk of other fractures were diabetes and a fall with hospitalization prior to transplantation, while 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.
CONCLUSION: Both general and transplant-specific risk factors were associated with a higher risk of fractures in kidney transplant recipients. Results can be used for clinical prognostication.
Core tip: We examined risk factors for major and other fractures in adult kidney transplant recipients. Increasing age and female sex were associated with an increased major fracture risk, while diabetes or cystic kidney disease as the cause of end-stage renal disease and increasing age of the kidney donor were the transplant-specific risk factors associated with an increased major fracture risk. Risk factors were variable across fracture locations (major vs other fractures). General and transplant-specific risk factors for fracture should be considered when assessing fracture risk in kidney transplant recipients. Different risk factors may need to be considered depending on the fracture location.
