A poster presentation at the ASN on whether patients’ with
pre-diabetes should be allowed to donate is receiving considerable publicity in
the media. Prediabetes is considered a relative contraindication to donation.
Here's a nice summary from an OPTN document posted on the web (p17):
"Type 2 diabetes mellitus is becoming increasingly prevalent in the
United States and one of its’ important complications is the development of
chronic progressive kidney disease.
Prediabetes represents an intermediate category of hyperglycemia,
which poses a significant risk of future type 2 diabetes mellitus, and
cardiovascular disease.
Important risk factors for prediabetes and diabetes include increasing
age, high risk ethnicity or race, obesity, and history of diabetes in a 1st
degree relative. Without active intervention, 6 to 23% of pre-diabetics
progress to diabetes within 1 year. The younger the individual with risk
factors for prediabetes, the higher the likelihood that diabetes and subsequent
kidney disease will occur in that person’s remaining lifetime.
The criteria for the diagnosis of prediabetes and diabetes are given
in table 1. Prediabetes includes individuals with impaired fasting glucose
(IFG), impaired glucose tolerance (IGT) or those with HgA1C between 5.7 and
6.4%. All potential donor candidates should be screened at a minimum with a
fasting plasma glucose. Since no single test will identify all individuals who
have prediabetes, consideration should be given to screening the highest risk
groups with an oral glucose tolerance test (OGTT) and a HgA1C.
While
prediabetes can be diagnosed with well-defined criteria and once established,
the progression to diabetes can be substantially reduced with lifestyle changes
and medications, it is not clearly known whether lifestyle modifications can
prevent the onset of prediabetes.
Candidates
with prediabetes should be considered to be at increased risk of future kidney
disease and may not be suitable candidates for kidney donation. Younger living
kidney donor candidates who have normal measures of glycemia (blood glucose,
HgA1C) but have multiple risk factors for future diabetes should be counseled
about the possible future risk of diabetes before proceeding to living
donation."
Back to the ASN poster....Medpagetoday.com reported:
"Chandran and colleagues conducted a retrospective, single-center
cohort study of 35 patients who gave up a kidney at their facility between 1990
and 2007.
These patients were contacted via a telephone to assess development of
any disease including diabetes, hypertension, proteinuria, and abnormal kidney
function.
At the time of donation, the mean fasting plasma glucose was about 109
mg/dL. Their mean age at that time was 48 and they were followed for a mean of
10 years.
During those 10 years, the researchers found that less than a third
(31.4%) still had high blood sugar and 17.1% had borderline diabetes. But only 11.4% developed full-blown diabetes, they found.
Overall, the mean fasting plasma blood sugar at that time was about
103 mg/dL, and the majority of patients (about 60%) had reverted back to normal
glucose, the researchers reported.
Chandran said the pre-donation characteristics that predicted worse
outcomes included being male, being younger, and having a higher fasting plasma
glucose at baseline.
A large proportion of patients (42.9%) also had high blood pressure
after 10 years, though the majority were being treated with antihypertensives.
Also, microalbuminuria occurred in only a few patients and kidney
function remained generally well preserved, the researchers added. Chandran concluded that further studies are needed to accurately
assess the risks of kidney donation for this population in order to set
consistent policies for donation."
What's
the bottom-line? We need more data. Therefore, don't change what you currently do: continue to consider
prediabetes as a relative contradiction. Chandran's study had limitations -
small sample, retrospective, single center, 10 year follow-up, and only presented as an
abstract. Besides, developing diabetes and hypertension in the context of a
single kidney adds a second hit for progressive renal injury (remember Barry
Brenner's two-hit hypothesis -link here and here).
