The construction of quality assessment model for highly time-dependency customers─ Examplified by ST-segment elevation myocardial infarction patients in the emergency department of a medical center

自2012年起，心臟疾病已躍居國人十大死因第二名，危害國人健康甚鉅，亦造成社會龐大的照護支出。在所有心臟疾病中，對生命影響最大的是急性冠心症候群，在我國有超過一半的急性冠心症患者被診斷為ST節段上升型急性心肌梗塞(STEMI)，死亡率為急性冠心症中最高。STEMI有黃金治療時間，及早治療能避免心肌持續壞死；經皮冠狀動脈介入治療（PCI）是目前治療STEMI的主流方法，病患症狀發生後12小時內，抵達急診90分鐘內為最適施行時間，惟PCI技術雖持續進步，病患抵達急診後等待PCI治療時間（D2B）持續壓縮，近年美國與台灣冠心症病患院內死亡率仍未顯著下降，顯示仍有醫療技術、D2B時間以外因素，影響STEMI病患預後。 本研究目的在於利用病患進入急診的前期生理指標、急診部門結構性資訊、治療過程面資訊、病患特性資料，分析影響STEMI預後及醫療耗用之重要因素，並探討上述預後及醫療耗用的重要影響因素，在壓縮D2B時間後，對病患預後改善之可能性。研究最後並建構急診STEMI病患預後醫療品質評估模型，以提供品質管理上之建議。 本研究為一回溯性病歷資料前瞻性分析，研究樣本為北區某醫學中心急診部門2010-2012年共662名STEMI病患。研究收集病患基本人口學、共病症、急診生理測值、心血管損傷資訊、處置紀錄、就醫時段、心電圖檢查及PCI治療等待時間，探討各變項對預後及醫療耗用之影響。本研究結果指標為病患當次就醫出院時預後狀態、當次就醫療耗用。預後狀態區分為預後不良或病況改善；預後不良包括病患院內死亡，以及病危自行出院。醫療耗用包括病患當次就醫在急診或住院的所有醫療費用及住院日數。本研究採用複邏輯式迴歸分析患者預後影響因素及建構預後醫療品質評估模型，以線性複迴歸模式分析影響醫療耗用之重要因素；研究並利用接收者操作特徵曲線分析工具（ROC curve）制定預後不良族群之風險分數閾值。 研究發現，病患年齡每增加一歲，預後不良機率增加1.07倍（95%CI：1.04-1.10，p<.0001）；上消化道出血或潰瘍病患的預後不良機率增加3.43倍（95%CI：1.26-9.38，p=0.016）；呼吸衰竭症狀病患的預後不良機率增加4.77倍（95%CI：2.03-11.19，p=0.0003）；腎衰竭或急性腎臟損傷病患的預後不良機率增加5.43倍（95%CI：2.15-13.74，p=0.0004）；休克病患的預後不良機率增加12.61倍（95%CI：5.75-27.64，p<.0001）。D2B時間若超過60分鐘，>65歲病患預後不良機會提高2.20倍；有呼吸衰竭症狀病患預後不良機會提高1.99倍；休克病患預後不良機會提高5.89倍；腎衰竭或急性腎臟損傷病患預後不良機會提高7.45倍。病患是否有PCI治療史、是否出現呼吸衰竭、血管梗塞數量和總醫療費用有顯著相關；透過將D2B壓縮到60分鐘之內，可降低二條血管栓塞患者5.7%醫療費用，約13,896元；可降低三條血管栓塞患者18.4%醫療費用，約46,062元。女性、有慢性阻塞性肺炎、呼吸衰竭，以及KILLIP級數愈高，住院日數愈長；透過將D2B壓縮到60分鐘之內，可縮短慢性阻塞性肺炎病患46.7%的住院日數，約10.5天。本研究利用病患年齡是否大於65歲、是否呼吸衰竭、腎衰竭或急性腎臟損傷、休克、上消化道出血或潰瘍條件發展之「病患特質預後風險評估模型」，訂定風險值10分以上即為預後不良高風險個案；加入D2B等候時間條件建構之「D2B預後風險評估模型」，訂定風險值23分以上即為預後不良高風險個案，風險評估模型能協助臨床及管理人員有效鑑別高風險族群，及時提供照護服務。 本研究於管理意涵上，揭示了病患分類管理之重要性。同樣為STEMI診斷之病患，應再進一步區分出預後不良高風險族群並進行例外管理，提供更迅速的檢查或處置服務。本研究結果在實務上可作為臨床指引修訂、管理流程改善方案之參考；學術上則提供了STEMI病患照護品質影響機制，以及成本效益分析的新方向，亦可作為其他治療時間急迫重症分析方法之參考。Cardiovascular diseases, including heart diseases, have been listed at the 2nd place of leading causes of death in Taiwan since 2012. Heart diseases, particularly acute coronary syndromes (ACS), affect human’s health and longevity while causing enormous burden of economic cost of the society. Over half of ACS patients are diagnosed as acute ST-segment elevation myocardial infarction (STEMI) of which is granted as a highly fatal disease and requires timely treatment to prevent further cardiac injuries. Percutaneous coronary intervention (PCI) is currently the primary treatment for STEMI patients, which is suggested to be administered within 12 hours after onset and within 90 minutes after admitted to emergency department (door-to-balloon time, D2B). To improve the care quality, this study aims to analyze factors associated with STEMI prognosis and the subsequent economic impacts. This study is a retrospective database prospective analysis. A total 662 STEMI patients admitted to the emergency department (ED) of a medical center in northern Taiwan during 2010-2012 were analyzed. Demographic background, comorbidity, physiological indicators, cardiac injury information, treatment record, time interval at presence, waiting time for electrocardiogram examination , and D2B were used to examine factors associated with prognoses and medical consumptions, the primary outcomes of this study. Poor prognoses included in-hospital death and discharge against medical advises. Medical consumptions included total medical expenses and total length of stay. Multiple logistic regression and general linear model were used. Receiver operating characteristic curve was utilized to determine the predictability of factors to patient’s poor prognosis. The study has demonstrated that patient’s age (OR=1.07;95% CI=1.04-1.10), and patients diagnosed with upper gastrointestinal hemorrhage or ulcer (OR=3.43; 95% CI=1.26-9.38), respiratory failure (OR=4.77; 95% CI=2.03-11.19), renal failure or acute renal injury (OR=5.43; 95% CI=2.15-13.74), or shock (OR=12.61; 95% CI=5.75-27.64) were significantly associated with poor prognosis. A relatively late PCI treatment (D2B>60 minutes) was also associated with folds of relative elevation of poor prognosis at 2.20, 1.99, 5.89, and 7.45 among patients older than 65 years old, with respiratory failure, with shock, and with renal failure or acute renal injury, respectively. PCI treatment history, presence of respiratory failure, and number of infarcted vessel were associated with total medical expenses. A prompt PCI treatment (D2B≦60 minutes) could reduce 5.7% (NT$ 13,896) and 18.4% (NT$ 46,062) of total medical expenses among patients with two and three infarcted vessels, respectively. Female, presence with chronic obstructive pulmonary disease (COPD) or respiratory failure, and higher KILLIP class were associated with total length of stay. A prompt PCI treatment (D2B≦60 minutes) could reduce 46.7% (10.5 days) of total length of stay among patients with COPD. This study has constructed a scoring system, including age >65 years old, and presence with shock, respiratory failure, renal failure or acute renal injury, and upper gastrointestinal hemorrhage or ulcer, to predict patient’s prognosis. Patients with >10 risk score are at high risk of poor prognosis. A high risk of poor prognosis was found among patients with >23 risk score while taking D2B time regimen into the predictive model. Although STEMI patients are generally classified as high urgent ED patients, to characterize the patients with extremely high fatality is especially important for emergency care. Providing prompt medical interventions to highly fatal patients is particularly beneficiary to both life-saving and medical cost containments. This study provides clues for future care quality improvements among STEMI patients, which also encompasses mechanistic pathways for health care quality, cost effectiveness, and management of time-dependency diseases in the future