急性心肌梗塞發生率、基本特質、資源利用及預後之探討

The study of Incidence, Basic Characteristics, Resource Utilization and Outcomes of Acute Myocardial Infarction

李統立(Thung-Lip Lee)

指導教授 ： 邱亨嘉

高雄醫學大學/健康科學院/醫務管理學研究所碩士在職專班/碩士(2011年)

摘要

研究背景及目的
急性心肌梗塞(AMI)臨床上可分類為ST波段上昇型心肌梗塞(STEMI)及非ST波段上昇型心肌梗塞(NSTEMI)，這樣的分類在疾病機轉、治療選擇、資源利用及預後都有一定的差異；但傳統上的研究都以整體心肌梗塞族群為研究對象。
了解心肌梗塞各項趨勢有助於了解進步及惡化的原因，並分別能找出持續進步以及改善惡化情況的方法。國外已有不少有關AMI發生率、醫療資源使用及預後趨勢的研究，近年來也開始有分別針對STEMI及NSTEMI的各種趨勢做分析研究，但台灣目前尚未有這方面的研究。所以本研究目的在於探討兩種急性心肌梗塞病患的發生率、人口學特質、疾病特質、就醫醫院特質、住院醫療資源利用以及當次住院中預後之趨勢演變，同時也探討急性心肌梗塞病患當次住院醫療資源耗用及當次住院中死亡之影響因子。
研究方法
本研究使用1996年至2007年「全民健康保險學術研究資料庫」基本資料檔的住院醫療費用清單明細檔。對象為這期間的AMI患者，擷取每年 ICD-9-CM之主診斷代碼為 410.XX(AMI)且首次出現者，經資料篩選後為94,637人。研究變項包括性別、年齡、心肌梗塞類型、察爾森共病症指數、醫院等級別、健保之分局別、就醫科別、侵入性治療選擇、總醫療費用、總住院天數、住院中有無併發症以及住院中有無死亡。先對所有變項進行描述性統計，再探討12年來所有AMI及兩種類型AMI病患的發生率、人口學特質、疾病特質、醫療資源使用以及住院中預後之趨勢，並以線性模式檢定其線性趨勢。住院資源耗用之影響因子以複線性迴歸分析探討，住院中死亡之影響因子則以對數迴歸分析探討。統計工具為SPSS 17.0統計套裝軟體。
研究結果
分析12年度之間共94,637名AMI患者，其中STEMI患者共55,078人(58.2%)，而NSTEMI患者共39,559人(41.8%)。AMI總數呈逐年增加趨勢，其中STEMI總數在2003年最高點後開始逐年減少，NSTEMI總數則逐年增加。校正後每十萬人口發生率方面，整體AMI及NSTEMI在各年齡層、男女族群都呈現增加趨勢，而STEMI在12年間發生率則是呈現先上升並在2002年左右開始下降的趨勢。
STEMI比例在2000年後逐年減少，由2000年67.8%高點減少至2007年的43.2%。STEMI的平均年齡呈現下降趨勢，而NSTEMI患者平均年齡則在上升中。其中STEMI患者小於45歲人口比例有緩慢增加的現象，NSTEMI患者75歲以上的比例增加幅度較大。AMI患者的性別比例並無明顯變化趨勢，男性比例遠大女性。就醫院層級別方面，AMI患者的醫學中心及區域醫院比例皆逐年升高，地區醫院比例從1996年的34.5%明顯降低至2007年的8.9%。
侵入性處置方面，AMI患者有進行PCI的比例明顯逐年增加，由1996年的12.4%增加至2007年的54.7%。STEMI患者增加比例高於NSTEMI(45.2% VS 26.0%,p<0.001)。與國外相比本國NSTEMI患者有進行PCI比例偏低。兩種類型心肌梗塞的平均住院天數呈不同趨勢變化，STEMI逐漸減少，NSTEMI在2001年後呈增加趨勢。AMI患者的總醫療費用有逐年增加趨勢;以複迴歸分析來探討，在控制其他變項後，STEMI患者的總醫療費用比NSTEMI組高出NT 3,081元(p<0.001)，平均住院天數方面兩組間則無明顯差異(p=0.294)。
另外兩種類型AMI當次住院死亡率都是呈現逐年下降趨勢，其中NSTEMI下降趨勢較為明顯。當次住院併發症發生比例則逐年緩慢增加，兩組間趨勢亦同。以對數迴歸分析，控制其他變項後，NSTEMI組的死亡率是STEMI組的1.42倍(p<0.001)。本研究也發現NSTEMI患者當次住院中死亡率比國外高(7.2% VS 3%~5%)。
結論與建議
本國整體AMI發生率仍然在增加中，主要是NSTEMI患者發生率的上升。NSTEMI患者的發生率，在整體AMI中所佔比例、住院天數及當次住院併發症都逐年增加中；加上平均年齡有上升現象，但侵入性處置比例卻比國外低，而當次住院中死亡率比國外高。未來無論在預防保健或臨床醫療，甚至研究上NSTEMI患者都將該是投入資源的重點。

關鍵字

不同類型心肌梗塞 ； 發生率 ； 資源使用 ； 住院中預後 ； 趨勢 ； 影響因子

並列摘要

Background: Acute Myocardial infarction (AMI) can be classified into ST segment Elevation Myocardial infarction(STEMI) and Non-ST segment Elevation Myocardial infarction(NSTEMI). Although many basic science and clinical evidences had shown that STEMI and NSTEMI have different pathophysiology, treatment option, resource utilization and even prognosis, but most of the clinical studies still focus on the entire AMI population instead of investigating STEMI and NSTEMI separately.
Monitoring the trends of incidence, resource rate, changing in hospital care or prognosis of AMI is important if we are to understand the nature of these raise or declines, with a view to continuing or avoiding it. There are growing in numbers of the foreign studies concerning different trends of AMI, even investigating STEMI and NSTEMI separately over the past few years. Currently, there is no publication concerning the trends of STEMI and NSTEMI, and even AMI as a whole in our country. The purpose of this study is to investigate the trends of incidence, demographical characteristics, disease characteristics, hospital characteristics, resource utilization and in-hospital prognosis of AMI. We also aimed to examine the determinants of resource utilization and in-hospital mortality of AMI.
Methods: We conducted 94.637 cases of AMI ( ICD-9-CM code 410.XX) from National Health Insurance Database provided by National Health Research Institute in Taiwan during Jan.1996 through Dec.2007. The study variables including sex, age, types of AMI, Charlson’s index score, hospital level, hospital location, physician specialty, invasive treatment option, total expenditure, length of stay(LOS), in-hospital complication and in-hospital mortality. We tested the different trends of AMI using linear model analysis. Multiple regression analysis was used to assess factors with an independent influence on the length of hospitalization stay and hospitalize expenditure. The determinants of in-hospital death were analyzed with logistic regression model. All data are analyzed by SPSS version 17.0.
Result: During the study period, there were 55,078 cases of STEMI and 39,559 cases of NSTEMI in total, which represent 58.2% and 41.8% of all AMI cases respectively. The age- and sex-adjusted incidence of AMI and NSTEMI were increasing over the study period, while those of the STEMI increased initially until 2002 and declined each year thereafter. The proportion of AMI that were STEMI decreased from 67.8% in 2000 to 43.2% in 2007.
From 1996 to 2007, mean age decrease in STEMI cases and increase in NSTEMI cases, increase incidence of AMI was noted especially in group older than 75 years. The proportion of males with AMI was higher than their counterparts with NSTEMI, and no significant changes of the proportion noted over the whole study period.
The proportion of cases admitted to local hospital declined dramatically form 34.5% in 1996 to 8.9% in 2007,while those admitted to medical centers and regional hospital increasing steadily.
The proportion of AMI cases underwent Percutaneous Coronary Intervention (PCI) increased from 12.4% in 1996 to 54.7% in 2007, representing a 3.4 fold of relative increase over the study period. The patients with NSTEMI have lower proportion of underwent PCI as compare to foreign country. Declines were observed in the length of stay of STEMI cases while different trend was noted over NSTEMI cases. Hospital expenditures were growing steadily every year. Classification of AMI (STEMI or NSTEMI) still being a determinant of hospital expenditures after adjusted others variable(p<0.001) in multiple regression model, but not for LOS (p=0.316).
The proportion of cases of AMI develop complication during hospitalization were increased in both STEMI and NSTEMI groups, while the proportion of in-hospital death were decrease gradually over the whole study period in both groups. Logistic regression analysis revealed that after adjusting for others variable, NSTEMI group still have a higher in-hospital mortality than STEMI( OR:1.42, p<0.0001). Beside, our study also found that the in-hospital mortality rate of NSTEMI was higher than others countries like France and Korea (7.2% VS 3~5%).
Conclusion and suggestion: The overall incidence of AMI in Taiwan was still increasing, mainly due to the growing incidence of NSTEMI. The proportion of AMI that were NSTEMI was raise. NSTEMI group also have increasing average age, LOS and in-hospital complication over the whole study period. However, NSTEMI group have lower proportion of revascularization as compared to STEMI, but higher in-hospital mortality rate as compare to other countries. NSTEMI should be the focus of clinical resource allocation and even investigation of AMI in the future.

並列關鍵字

Acute myocardial infarction ； Incidence ； Resource Utilization ； Prognosis ； Trends ； Determinants.

參考文獻

英文文獻

Abildstrom, S. Z., Rasmussen, S., & Madsen, M. (2002). Significant decline in case fatality after acute myocardial infarction in Denmark--a population-based study from 1994 to 2001. Scand Cardiovasc J, 36(5), 287-291.

Armstrong, P. W., Fu, Y., Chang, W. C., Topol, E. J., Granger, C. B., Betriu, A., et al. (1998). Acute coronary syndromes in the GUSTO-IIb trial: prognostic insights and impact of recurrent ischemia. The GUSTO-IIb Investigators. Circulation, 98(18), 1860-1868.

Chen, J., Normand, S. L., Wang, Y., Drye, E. E., Schreiner, G. C., & Krumholz, H. M. (2010). Recent declines in hospitalizations for acute myocardial infarction for Medicare fee-for-service beneficiaries: progress and continuing challenges. Circulation, 121(11), 1322-1328.

Chen, C. S., Liu, T. C., Chiu, W. T., & Lin, H. C. (2007). Impact of hospital and physician characteristics on medical expenditures for acute myocardial infarction hospitalization. Int J Cardiol, 121(1), 127-129.