<qa>  What is the name of the patients who have been hospitalized in recent months?1. Patients To be eligible for the study, patients have to meet all of the following criteria: 1 have received maintenance PD for more than 3 months at Far Eastern Memorial Hospital, 2 have high CPP level 55, and 3 have chest X-ray proven aortic calcification or coronary artery calcification proven before. Patients are excluded if they have any one of the following conditions: 1 had been hospitalized in recent 3 months due to severe comorbid diseases, 2 are hypersensitive to alendronate or any of its components, 3 have esophageal diseases 4 are not able to stand or sit upright for 30 minutes, 5 have refractory hypocalcemia, or 6 patients who are pregnant. 