In an article recently published in AJKD, Lam et al describe the risk of gout in 1988 living kidney donors compared to a matched cohort of 19,880 non-donors over a median follow-up of 8.4 years. The authors found that the risk for gout was significantly higher in donors, who were more likely to have received a prescription for allopurinol or colchicine. The risk of gout, however, was not different in the donors when compared to the general population. These results are similar to the recent study by Muzaale et al looking at NHANES data, where the risk of end-stage renal disease (ESRD) was only higher when compared to a matched cohort of non-donors but not the general population.
We have come to realize that the general population may not be the ideal comparison group since potential donors are carefully screened for co-morbidities and kidney disease–specific risk factors, and are therefore a healthier subset of the general population. However, which “matched cohort” is the ideal comparator remains a matter of debate. Healthy, matched non-donors also have unique characteristics and different competing risks for ESRD and mortality than donors. It is obvious that performing randomized trials and selecting genetically identical populations will be impossible, and physicians will need to base our recommendations on observational studies.
There is a shortage of kidney donors and high demand for organs, and these articles pose the following questions:
- How should clinicians interpret these results and advise our potential donors?
- Are we now obliged to discuss the risk of gout with potential donors as we now discuss the risk for ESRD?
- Could we develop models to predict these risks?
- Do physicians and patients really understand differences between relative and absolute risks?
This interesting and novel study without doubt adds to the literature, but the absolute risk for all these outcomes is very small. Applying these findings to clinical practice remains an area of active exploration.
Dr. Magdalena Madero
AJKD Blog Contributor