老年人罹患多重慢性疾病，住院後造成身體功能衰退，使得出院後短時間內再住院情形增加。再住院不僅衝擊老年人的健康，亦增加照顧者的負荷及醫療費用成本的增加，有效的控制非計畫性的再住院，可提高醫療品質、促進健康目的，作為提升照護品質的參考。本研究利用醫院電腦醫療資訊(NISS)系統，採回溯性病例對照設計方式，收集2014年1月至2016年6月期間，65歲以上登錄在高齡醫學科住院長者資料，選取50位非計畫性再住院老年病人為病例組，以1：3的比例取年齡相距5歲以內、性別、第一次入住時間相距一個月內的非再住院老年病人為對照組，以卡方檢定分析人口學特徵、住院狀況，進而以邏輯斯迴歸分析結果發現由急診入院者、罹患慢性疾病，如:罹患惡性腫瘤疾病者，血鈉離子濃度異常者，血鉀離子濃度異常者為非計畫性再住院之危險因子。藉由醫療團隊介入性的治療措施，提供慢性疾病的整合性照護、多重用藥的調整及簡易的營養評估篩檢，矯正電解質不平衡狀況及增加飲食營養的需求，改善精神狀況、提升自我照顧能力，有效減少老年病人再住院機率。

Elderly people have poor reserve and multimorbidity and are at a high risk of functional decline following admission while also having high rates of readmission. Readmission not only affects elderly patient's health condition but also increases the burden on caregivers and medical services. Lowering readmission rates can improve the quality of medical services and the health of elderly people. This retrospective case control study collected data from Taiwan's NISS system; participants aged 65 and older admitted to the geriatric evaluation and management unit between January 2014 and June 2016 were recruited. A total of 50 elderly people were readmitted during the study period. After controlling for age and sex, 150 elderly people admitted during the study period without readmission were recruited as the control group. The chi-square test was conducted for demographic characteristics and admission condition; logistic regression analysis revealed that patients being admitted from the emergency department, having a diagnosis of malignancy, having abnormal Na levels, and having abnormal K levels were independent risk factors for readmission. In summary, readmission for elderly people must be avoided when possible. Providing integrated care for multimorbility, adjusting polypharmacy, assessing nutritional needs, correcting electrolyte imbalance, and improving patients' self-care ability may reduce readmission rates among elderly people.