背景:食道靜脈瘤出血的病人容易產生感染併發症，連帶使再出血現象惡化及增加死亡率。然而，食道靜脈瘤出血的病人使用預防性抗生素對於死亡率及醫療費用的影響一直未有良好的證據評估。

目的:評估食道靜脈瘤出血的住院病人使用預防性抗生素對於死亡率及醫療費用的影響。

方法: 採用 2005 至 2010 年全民健康保險學術資料庫-「住院醫療費用清單明細檔」、「住院醫療費用醫令清單明細檔」及「承保資料檔」。納進診斷為食道靜脈瘤出血且接受靜脈瘤內視鏡結紮術之病人資料，包含人口學、醫療費用、住院天數、出院情況、出院診斷碼及藥物碼，並依此先將病人分為有感染與無感染組，再將無感染病人分為使用預防性抗生素及無使用預防性抗生素兩組。先分析使用預防性抗生素及無使用預防性抗生素兩組之人口學及臨床特徵分布，再以邏輯斯迴歸分析死亡率之相關因子。

結果: 2005至2010年間，共有1067人次住院診斷為食道靜脈瘤出血且接受靜脈瘤內視鏡結紮術，其中819人次住院時無感染症發生，392人次接受預防性抗生素，另外427人次則無。在這六年內，使用預防性抗生素的比率從39.5%增加到57.4，有顯著性增加，但是細菌感染率則無顯著變化。預防性抗生素較常被使用在有肝膽惡性腫瘤的病人。以多變數邏輯斯迴歸分析非感染組死亡的相關因子，發現肝膽惡性腫瘤、需要住加護病房、休克及預防性抗生素皆為顯著因子。在調整過其他人口學及共病因子後，預防性抗生素對死亡率的Odds ratio 是3.179 (95% 信賴區間 1.627-6.210)。跟無使用預防性抗生素組相比，預防組之住院天數是另一組的1.8倍，總醫療費用跟藥物費用則分別是2.5跟2.4倍。

結論：食道靜脈瘤出血的病人使用預防性抗生素並不能降低死亡率，病人的死亡率跟疾病的嚴重程度及肝膽惡性腫瘤有關。

Patients with esophageal variceal bleeding are prone to having infections, which may aggravate rebleeding and increase mortality. However, the effects of antibiotic prophylaxis on mortality and medical cost in patients with esophageal variceal bleeding are not well described.

Purpose： This study aimed to evaluate the effect of antibiotic prophylaxis on the mortality and medical cost of patients hospitalized with esophageal variceal bleeding.

Method：De-identified patient data from the National Health Insurance Database, derived from the Taiwan National Health Insurance Program was reviewed, to enroll 1067 admissions for esophageal variceal bleeding and receiving endoscopic ligation between January 1, 2005 and 31 December, 2010. We collected patients’ demographic, medical cost and hospitalization data including hospital stays and conditions of discharging, and reviewed diagnostic codes to determine infectious diseases and comorbid disorders of their hospitalizations, then reviewed ATC codes to determine antibiotic prophylaxis in non-infection group. Patients were divided into an antibiotic prophylaxis group and non-prophylaxis group and odds ratios (ORs) were determined for hospital mortality.

Results：Of the total 1067 admissions for esophageal variceal bleeding and receiving endoscopic ligation, there were 819 admissions for esophageal variceal bleeding (EVB) without infection. Among the 819 admissions, prescription of antibiotics was placed into the prophylaxis group (n=392), and the remaining was placed into the non-prophylaxis group (n=427). The proportion of antibiotic prophylaxis in EVB admissions significantly increased with year from 39.5 % to 57.4% during 2005 to 2010 in non-infection admissions. But there was not significant difference between incidence of bacterial infection during the six years. More antibiotic prophylaxes were used in patients with malignant neoplasm of liver and intrahepatic bile ducts which is an independent risk factor of mortality in our analysis as other studies. ICU care and shock are significantly associated with mortality. After logistic regression analyses adjusted by the patients’ demographic and clinical characters, the odds ratio in patients with antibiotic prophylaxis for hospital mortality was 3.179 (95% confidence interval (CI) 1.627 - 6.210). Compared to the non-prophylaxis group, the ratios of hospital stay, total medical expense and prescription cost were 1.8, 2.5, and 2.4, respectively.

Conclusion：Antibiotic prophylaxis for patients with esophageal variceal bleeding did not reduce mortality. Mortality of non-infectious patients with esophageal variceal bleeding was significantly associated with the severity of illness (ICU care and shock) and hepatic malignancy.

Contents
Acknowledgments I
Chinese Abstract II
English Abstract IV
Table of Contents VII
List of Figures and Tables IX
Chapter 1 Introduction
1.1 Background...........................................1
1.2 Controversial Issue..................................8
1.3Aim...................................................9
Chapter 2 Materials and Methods
2.1 Study Design......................................9
2.2 Data Source......................................10
2.3 Definitions of Samples...........................11
2.4 Variables........................................12
2.5 Statistical Analyses.............................14
Chapter 3 Results
3.1 Clinical characters of patients with infection....15
3.2 Characteristics of patients without infection.....17
3.3 Risk factors of mortality in EVB patients without infection...............................................24
Chapter 4 Discussion and Conclusion
4.1 Discussion........................................27
4.2 Limitation........................................31
4.3 Conclusions.......................................32
References..............................................33
Appendix: ICD9-CM code..................................36

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