OBJECTIVE Information relating the outcome of percutaneous coronary intervention to diabetes mellitus or hypertension is limited. The study objective was to describe the outcome in patients undergoing percutaneous coronary intervention in relation to diabetes and hypertension. METHODS Data were extracted from 5 national registers: the Swedish Coronary Angiography and Angioplasty Register (all percutaneous coronary interventions), the Prescribed Drug Registry (all prescribed pharmaceuticals purchased in Swedish pharmacies), the Swedish Hospital Discharge Register (data on myocardial infarction, revascularization, stroke, and congestive heart failure from in-hospital and specialist health care), and the National Population Register and Cause of Death Register (data on death). We included all "first percutaneous coronary interventions" between January 1, 2006, and December 31, 2008 (n=44,268; followed an average of 1.9 [± 0.9] years). RESULTS Mortality was 6.4% and highest in patients with diabetes plus hypertension. Hypertension per se did not increase mortality or the risk for repeat intervention, but carried a 10% increased risk for subsequent myocardial infarction, increasing to a 4-fold increase when combined with diabetes. Stroke occurred in 2%; the importance of hypertension was evident in nondiabetic patients, but even stronger in diabetic patients. Congestive heart failure caused hospital admission in 8%, with a negative influence from hypertension with and without diabetes. CONCLUSIONS After percutaneous coronary intervention and with modern pharmacotherapy, diabetes had a negative effect on the outcome, especially when combined with hypertension. Hypertension per se was not associated with increased mortality but with an increased risk for myocardial infarction, stroke, and congestive heart failure, probably related to widespread coronary artery disease. Improved diabetes care might improve the prognosis.