目標：參考Andersen第一階段醫療服務利用行為模式，探討台灣地區健保居家照護使用者之急診醫療利用情形，以及預測急診就醫罹病發生之影響因素。方法：採回溯性世代追蹤研究設計，資料來源為國衛院發行之全民健康保險資料庫1999至2008年「居家照護特殊需求檔」，研究對象為2000至2008年居家照護新收案個案102,680人；使用卜瓦松迴歸模式預測影響急診就醫全病因與主要系統疾病病因別之罹病發生因素。結果：居家照護使用者急診就醫以循環系統疾病發生密度最高（441.41人次/10^3人年）。研究樣本以男性、65歲以上者、投保所在地於東區分局和大都會區、第二至四類居家護理資源耗用群、具有重大傷病和長期呼吸持依賴者，共存疾病指數3分以上、具有腫瘤、糖尿病與充血性心衰竭合併症者，其急診就醫全病因罹病風險較高。結論：研究發現健保居家照護使用者常因循環、呼吸、泌尿生殖系統等疾病而到急診就醫，特別是循環與泌尿生殖系統疾病，年長者之急診就醫相對風險倍增，值得居家照護提供者進一步檢視其照護需求。

Objectives: With reference to Phase I of Andersen's Behavioral Model of Health Services Utilization, the researcher investigated emergency department utilization by home-care service recipients with National Health Insurance (NHI) in Taiwan, and examined the predictive factors affecting the risks of morbidity from emergency department utilization. Methods: This design was a retrospective cohort study. Data came from the "home care specific file" in the National Health Insurance Research Database between 1999 and 2008. The subjects were 102,680 newly NHI homecare service users between 2000 and 2008. The Poisson regression model was used to predict the factors affecting emergency department utilization, morbidity from all causes, and major system classifications. Results: The NHI home-care service users experienced the highest incidence of circulatory system diseases (441.41/10^3 person-year). This study showed that a higher relative risk ratio for emergency department utilization and morbidity from all causes were found in male users, those aged 65 and older, those living in urban areas, Resources Utilization Group Category 2-4 home care consumers, major illness/injury and long-term respiratory dependent cases, cases with a Charlson Comorbidity Index score of 3 and above, and cases with tumors, diabetes and congestive heart failure complications. Conclusions: Based on the findings of this study, the top three reasons for emergency department utilization by home-care service recipients were diseases of the circulatory, respiratory, and urinary/reproductive systems. The adjusted relative risk of emergency department utilization increased dramatically among elders, especially for diseases of the circulatory and urinary/reproductive systems. Health care providers should pay close attention to the care needs of home-care service recipients.