February 2004 - Patients who develop diabetes shortly after kidney transplantation have poorer short-term outcomes than those who had the disease before transplant, according to a Penn State Milton S. Hershey Medical Center study.

"Because patients with diabetes often pose many medical challenges due to the complications of the disease, it was surprising to see that these patients who'd been dealing with diabetes for years, ended up better off than the patients who only developed diabetes after their transplants," said Robert Gabbay, M.D., Ph.D., associate professor of medicine, co-director, Penn State Diabetes Center, and principal investigator of the study, which appeared in the December 2003 issue of Transplantation Proceedings. "Overall, patients who developed post-transplant diabetes were most vulnerable to kidney rejection, infection and additional hospitalization."

The study included 181 kidney transplant patients at Penn State Milton S. Hershey Medical Center from January 1999 to December 2000. The patients were divided into three groups: those who had diabetes prior to kidney transplant, those who developed diabetes mellitus within 24 weeks after transplant; and those who did not have diabetes mellitus before or after transplant. Data was collected before and after the patients' transplants.

Results showed that about 22 percent of previously non-diabetic patients developed post-transplant diabetes within six months of kidney transplant. About 57 percent of those patients developed an infection compared to 35 percent of patients who had diabetes prior to transplant and 21 percent of patients who did not have or develop diabetes. Patients who developed post-transplant diabetes also were more likely to have recurrent infections than the other two patient groups.

"We would expect that patients who were recently diagnosed with diabetes wouldn't yet be suffering from complications, yet our study showed that they do have poorer kidney transplant outcomes," Gabbay said.

Although few in number, previous long-term studies showed that the standard post-transplant drug therapies taken to help patients avoid organ rejection can actually cause patients to develop diabetes. Limited data form other studies also has suggested that post-transplant diabetes is associated with higher rates of long-term sickness and death primarily due to an increase in infections or heart and vascular problems.

"This study focused on the first six months after transplant because short term rehospitalization is a great concern for transplant patients," Gabbay said. "If bad outcomes start early, then earlier interventions may be helpful for the long-term health of the patients." Gabbay said the health information presented in the long-term outcomes studies may include influences from other medical complications of diabetes. Focusing on the short term may remove any influences from the long-term complications of diabetes and allow the researchers to focus on the glucose values. Tight control of glucose, or blood sugar, with the use of insulin is important for all patients with diabetes to remain healthy.

"We believe that the poor outcomes in those who develop diabetes after kidney transplant may have something to do with glucose levels and we plan to study that next," Gabbay said. "We hope that medical interventions early could lead to better outcomes for these patients in the long run."

Co-authors on the study were: T.F.M. Saleem, M.D., fellow; K.E. Cunningham, medical student, Penn State College of Medicine, C.S. Hollenbeak, Ph.D., assistant professor of surgery and health evaluation sciences; and E. J. Alfrey, M.D., professor of surgery, Penn State College of Medicine, Penn State Hershey Medical Center.