根據國民健康局統計台灣十大死因中與腹主動脈瘤患者具有高度相關的慢性疾病有六種，為提高治療成效與慢性疾病術後併發症的預防，故選擇作為本次研究的主要研究對象。 我們選擇了CHAID決策樹分析法演算現有的資料，並透過條件式邏輯斯迴歸提高準確度，進而歸納出術後檢驗值可能具有顯著性的時間點作預防性的投藥和術後併發症的預防。 研究結果顯示慢性阻塞性肺疾病患者，術後第七天做凝血脢原時間檢驗；其他心臟疾病患者，分別在術前做肌酸酐檢驗、術後第一天做尿素氮檢驗、術後第四天做纖維蛋白降解產物檢驗、術後第一個月做白血球、血紅素、血容比等檢驗；慢性腎臟疾病患者，術前做血紅素、血容比、白蛋白、尿素氮(檢驗值介於17到30的患者除外)、肌酸酐等檢驗，術後第一天做尿素氮檢驗，檢驗值介於17到30的患者才具有顯著性。從以上這些時間點中發現檢驗值有異常情況，建議依異常檢驗值項目，可能導致的併發症作預防性投藥治療，可大幅減少住院天數。 According to the statistics of the Bureau of Health Promotion, six chronic diseases out of the ten leading causes of deaths were significantly associated with patients with abdominal aortic aneurysms in Taiwan. The purpose of this study was to provide approaches for promoting the treatment outcomes and preventing postoperative complications for patients with chronic diseases. CHAID (Chi-square Automatic Interaction Detector) decision-tree analysis was utilized to calculate the existing data. Conditional logistic regression model was applied to increase accuracy. The results of CHAID approach provided the most significant time point that could be used for prophylactic medications to prevent postoperative complications. Our findings indicated that if the results of following tests were abnormal, it was suggested to give prophylactic medications according to the test items for preventing complications and significantly reducing the number of hospitalization days. These tests including prothrombin time at the seventh day after surgery for the patients with chronic obstructive pulmonary disease (COPD); pre-operative creatinine test, BUN test on the first postoperative day, FDP test on the fourth first postoperative day, as well as WBC account, Hb, and Hct tests at one month after surgery for the patients with cardiovascular diseases; preoperative tests for Hb, Hct, albumin, BUN (patients with the test values between 17-30 are excluded), and creatinine for the patients with chronic kidney disease.