By Emilio Poggio, MD
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Metabolic syndrome is common among prospective living kidney donors. Because this condition is treatable simply with lifestyle interventions (healthy diet, exercise and weight loss), and because the health of living kidney donors is critically important at the time of donation and in the long term, diagnosing members of this relatively healthy population and educating them about how to treat metabolic syndrome is essential.
Emilio Poggio, MD
We conducted a retrospective observational study examining whether lifestyle practices that promote weight loss and physical activity during the kidney donor evaluation process could lead to improved health.
Probing renal-metabolic syndrome connections
Metabolic syndrome is a constellation of abnormalities that have been associated with cardiovascular disease and all-cause mortality in the general population.
The relationship among metabolic syndrome, kidney function and underlying renal histology in otherwise healthy adults is unclear. Therefore, we studied the prevalence of metabolic syndrome in living kidney donors and its association with kidney function and histology at the time of donation. We then studied whether pre-donation metabolic syndrome was associated with impaired post-donation renal function recovery. We also studied the impact of post-donation body weight changes on metabolic syndrome and its components.
Our results showed that metabolic syndrome was present in 12.2 percent of prospective kidney donors who actually ended up donating a kidney. Donors with metabolic syndrome were more likely to have chronic renal histological changes such as mild glomerulosclerosis and interstitial fibrosis on implant biopsies performed at time of donation when compared with donors who had no metabolic syndrome (29.0 percent vs. 9.3 percent, p < 0.001).
This finding was associated with impaired kidney function recovery following kidney donation. However, it is important to note that at last follow-up, we observed reversal of metabolic syndrome in 57.1 percent of donors with pre-donation metabolic syndrome, while only 10.8 percent of donors developed de novo metabolic syndrome (p < 0.001).
In addition, we noted that changes in body mass index after donation led to changes in each of the components of metabolic syndrome. Weight loss led to improvements in blood pressure, triglycerides, HDL cholesterol and fasting blood glucose levels, all of which are components of metabolic syndrome.
Focusing on weight loss
Cumulatively, it appears from our results that weight loss may be the main driver for the improvement of metabolic syndrome components. Therefore, advising, promoting and supporting lifestyle practices, including dietary and activity changes that promote weight loss during the donor evaluation process (before and after donation), should be actively advocated.
While this was a retrospective study, and therefore not an interventional trial where a specific program was implemented, based on these results we advise all prospective living kidney donors at our center who have metabolic syndrome to engage in healthy lifestyle modification practices.
Although our study did not evaluate cardiovascular outcomes, based on available data, metabolic syndrome can be used as a simple and practical tool to identify and counsel patients who might be at high risk for future cardiovascular disease.
Dr. Poggio is a staff member of the Department of Nephrology and Hypertension in Cleveland Clinic’s Glickman Urological & Kidney Institute. He also has joint appointments in Cleveland Clinic’s Transplant Center, and in the Lerner Research Institute’s Department of Immunology.