Objective To investigate the optimal strategy for preventing contrast medium-induced nephropathy(CIN)in elderly diabetic patients undergoing percutaneous coronary intervention (PCI).Methods Two hundred and fifty-six consecutive elderly diabetic patients who underwent percutaneous coronary interventions were enrolled.Patients were randomized into iopromide (A,n=85),iopromide plus hydration therapy (B,n=87),and iodixanol (C,n=84)group.Serum creatinine (SCr) levels were assessed at baseline and 3 d after the procedure.The primary end point was the incidence of CIN,which was defined as a 25% increase of SCr concentration 48 h after the procedure.Results The amount of contrast medium used,baseline SCr levels,and SCr clearance were not significantly different among the 3 groups.CIN incidence was lower in group B than in group A (8.0% vs 18.8%,P<0.05),and was not significantly different between group B and group C (13.1%).Conclusion Compared with single use of contrast medium,the combined hydration therapy is extremely important for the prevention of contrast medium-induced nephropathy in the elderly diabetic patients who are scheduled to undergo PCI.