The risk of diabetes was independent of other factors that are known to increase the risk of diabetes. The researchers analyzed US Renal Data System data on approximately 20,000 Medicare beneficiaries undergoing kidney transplantation between 1995 and 2003. None of the patients had diabetes before their kidney transplant. Treatment with sirolimus was analyzed as a possible contributor to the risk of diabetes developing after transplantation, along with other known and potential risk factors. The results suggested a higher rate of post-transplant diabetes among patients treated with sirolimus, compared to other anti-rejection drugs. Depending on which additional drugs they received, diabetes risk was 36 to 66 percent higher for patients receiving sirolimus. Separate analysis of patients who stayed on the same anti-rejection drugs throughout the first year after transplantation showed similar results. The increase in risk was unrelated to any of the other drugs used in combination with sirolimus, or to other risk factors such as age, race/ethnicity, or obesity. Diabetes is a serious and increasingly common complication occurring after kidney transplantation. Patients who develop diabetes after transplantation have roughly the same risk of transplant failure as patients who develop acute transplant rejection.