Metabolic syndrome - a new risk factor for impaired kidney function

A three-year multi-center study of kidney-pancreas transplant recipients has identified a new risk factor for impaired kidney function, which may help physicians refine their treatment strategies.

Researchers from Wake Forest University Baptist Medical Center and colleagues reported their findings at the 6th Annual American Society of Transplant Surgeons State of the Art Winter Symposium in Scottsdale, Ariz.

The researchers found that metabolic syndrome, a cluster of symptoms that increase the risk of heart disease, is also a risk factor for deterioration of kidney function in simultaneous kidney-pancreas transplant recipients. The risk is especially high when the pancreas transplant fails. The study involved 298 patients at 25 transplant centers.

"The findings suggest that we need to do whatever we can to keep the transplanted pancreas functioning because it may protect against development of long-term kidney transplant dysfunction," said Jeffrey Rogers, M.D., a Wake Forest transplant surgeon. "The findings also underscore the importance of controlling weight, blood pressure, blood sugar and cholesterol - the variables that define metabolic syndrome."

In kidney and pancreas transplantation, advances in immunosuppressive drug therapy have significantly reduced the risk of acute rejection. Transplant surgeons are now increasingly focused on developing strategies to prevent or slow a gradual deterioration in kidney function that can lead to the need for a second transplant.

Previous research had shown that metabolic syndrome is a risk factor for chronic deterioration of kidney function in kidney transplant recipients. However, the effect of metabolic syndrome on the outcome of simultaneous kidney-pancreas transplantation and the significance of having a functioning pancreas transplant in these patients has not been previously described.

About 700 kidney-pancreas transplants are performed each year in the United States. The procedure is performed in patients who have either type 1 or type 2 diabetes and kidney failure. The pancreas produces insulin, a hormone that helps regulate levels of blood sugar. People with diabetes do not produce enough insulin or cannot use insulin effectively. The primary function of the kidneys is to filter waste products and extra water from the body by producing urine.

Metabolic syndrome is diagnosed when someone has at least three of these following: body mass index greater than 30 or waist size larger than 40 inches for men or 35 inches for women, high levels of triglycerides, low levels of "good" cholesterol, high blood pressure or high levels of blood sugar.

The study followed 298 patients for three years after simultaneous kidney-pancreas transplantation. The researchers found that the prevalence of metabolic syndrome decreased from 59 percent prior to transplant to 19 percent one year after transplant. This would be expected because the transplant would eliminate diabetes - one of the components of metabolic syndrome.

Patients who had metabolic syndrome one year after transplant were 10 times more likely to have reduced kidney function three years after transplant than patients who did not have metabolic syndrome. The researchers analyzed how function of the transplanted pancreas affected the relationship between metabolic syndrome and kidney function and found that patients with metabolic syndrome who developed early pancreas transplant failure had the highest risk of developing long-term kidney dysfunction.

Rogers said that further study was needed to better understand the role a functioning pancreas transplant plays in preserving kidney transplant function in patients with metabolic syndrome so that long-term survival of both organs can continue to be improved.