Kidney Weight Matters -- MEDICA - World Forum for Medicine

Kidney Weight Matters

The results suggest that compatibility between a donated kidney's weight and the weight of the recipient could improve the success of transplantation.

Few studies have examined the direct impact of matching a donated kidney's weight to the weight of a transplant recipient. To investigate, Jean Paul Soulillou and his colleagues studied how kidney weight to recipient weight ratios affect the long-term kidney health of individuals who receive transplants.

After following 1189 patients for an average of 6.2 years after transplantation, the investigators found that the greater the incompatibilities of weight ratios, the more likely patients were to develop kidney problems. Specifically, a low kidney weight to recipient weight ratio (< 2.3 g/kg) increased the risk of developing inadequate kidney filtration, excess urinary protein excretion, hypertension, kidney scarring, and transplant failure. This low kidney weight to recipient weight ratio was associated with a 55 percent increased risk of transplant failure after two years of follow-up.

"This information is potentially useful for thousands of transplantations and provides a new opportunity to improve long-term graft survival," said Soulillou. He added that the clinical impact of the kidney weight to recipient weight ratio is similar to what was described decades ago for human leukocyte antigens, which are the major compatibility markers used today to determine transplant-recipient matches.

Researchers noted, however, that because living donors made up less than one percent of the study's cases, it is not clear if the findings hold true for recipients other than those who receive deceased donor kidneys. They added that kidneys from very young pediatric donors might be associated with different outcomes, particularly if two kidneys from one child are transplanted into an adult, as is commonly done. According to a 2009 study, a single kidney from a very young deceased donor maintains the health of an adult with kidney failure. Other studies have reported more complications when single kidneys from very young donors are transplanted into adults.; Source: American Society of Nephrology