Background In the general population, high serum uric acid concentration is a risk factor for gout. It is unknown whether donating a kidney increases a living donor's risk of gout as serum uric acid concentration increases in donors after nephrectomy. Study Design Retrospective matched cohort study using large health care databases. Setting & Participants We studied living kidney donors who donated in 1992 to 2010 in Ontario, Canada. Matched nondonors were selected from the healthiest segment of the general population. 1,988 donors and 19,880 matched nondonors were followed up for a median of 8.4 (maximum, 20.8) years. Predictor Living kidney donor nephrectomy. Outcomes The primary outcome was time to a diagnosis of gout. The secondary outcome in a subpopulation was receipt of medications typically used to treat gout (allopurinol or colchicine). Measurements We assessed the primary outcome with health care diagnostic codes. Results Donors compared with nondonors were more likely to be given a diagnosis of gout (3.4% vs 2.0%; 3.5 vs 2.1 events/1,000 person-years; HR, 1.6; 95% CI, 1.2-2.1; P < 0.001). Similarly, donors compared with nondonors were more likely to receive a prescription for allopurinol or colchicine (3.8% vs 1.3%; OR, 3.2; 95% CI, 1.5-6.7; P = 0.002). Results were consistent in multiple additional analyses. Limitations The primary outcome was assessed using diagnostic codes in health care databases. Laboratory values for serum uric acid and creatinine in follow-up were not available in our data sources. Conclusions The findings suggest that donating a kidney modestly increases an individual's absolute long-term incidence of gout. This unique observation should be corroborated in future studies.
Bibliographical noteFunding Information:
Support: This project was conducted at the Institute for Clinical Evaluative Sciences (ICES) Western Site. ICES is funded by an annual grant from the Ontario Ministry of Health and Long-Term Care. ICES Western is funded by an operating grant from the Academic Medical Organization of Southwestern Ontario. This project was conducted with members of the provincial ICES Kidney, Dialysis and Transplantation Research Program ( www.ices.on.ca ), which receives programmatic grant funding from the Canadian Institutes of Health Research. Dr Lam was supported by the Clinical Investigator Program at Western University and by a Kidney Research Scientist Core Education and National Training Program (KRESCENT) postdoctoral fellowship award. Dr Garg was supported by a Dr Adam Linton Chair in Kidney Analytics and Application. The opinions, results, and conclusions reported in this article are those of the authors and are independent of the funding sources. The funding sources did not influence any aspect of this study.
Financial Disclosure: Dr Garg received an investigator-initiated grant from Astellas and Roche to support a Canadian Institutes of Health Research study in living kidney donors, and his institution received unrestricted research funding from Pfizer. The other authors declare that they have no other relevant financial interests.
© 2015 The Authors.
Copyright 2015 Elsevier B.V., All rights reserved.
- Cohort study
- diagnostic codes
- donor outcomes
- health administrative data
- health outcomes
- kidney donation
- living kidney donor
- renal transplantation
- uric acid