心肌梗死后再住院率25年来基本不变

《内科学文献》(Annals of Internal Medicine)7月3日发表的一项研究显示，尽管在1987 ~2010年这段时间内，急性心肌梗死(MI)的治疗取得显著进展，但30天再住院率基本保持不变。虽然再住院率从1987年的23%降至2010年的19%，但该差异无统计学意义(Ann. Intern. Med. 2012; 157:11-18)。

在这项研究中，梅奥医院的心脏病学研究员Shannon Dunlay博士及其同事利用罗切斯特流行病学计划数据库，从明尼苏达州奥姆斯特德县3个医疗机构的病历中提取3,010例病例进行了分析。患者的平均年龄为67岁，在研究期间该平均年龄无变化。

分析结果显示，院内存活率从1987年的89%增至2010年的96%。在1987~2010年期间，高血压(61%→69%)、高脂血症(50%→68%)、糖尿病(22%→24%)和肥胖(体重指数≥30 kg/m²)(33%→38%)等合并症的发生率显著改变。

治疗方面的改变包括，纤溶治疗率显著降低(28%→1%)，再灌注/血运重建(64%→69%)、经皮冠状动脉介入(PCI)(51%→63%)和血管造影(76%→85%)应用率显著增加。中位住院时间从5天降至3天，这一改变同样显著。

并发症发生率增加与治疗方面的这些改变相关。在接受PCI治疗的患者中，10%发生并发症，包括血管或出血并发症(6%)、卒中(0.3%)和肾衰竭(5%)。在血管或出血并发症中，63%为通路部位并发症，其中多数为腹股沟血肿。

接受纤溶治疗的患者的并发症发生率较低(2%)。在接受冠状动脉旁路移植术(CABG)的患者中，2%发生相关卒中。在进行血管造影且进行或不进行再灌注治疗的患者中，8%发生并发症。多数这些患者(5%)患有急性肾衰竭，其中3例患者需透析。其他患者出现血管或出血并发症。

561例患者(19%)出院后30天需再次住院，这些患者共住院643次：484例患者再住院1次，72例再住院2次，5例再住院3次。3%(87例)的患者在30天内死亡，其中19例在再次住院期间死亡。

再住院率在1987~1992年期间为23%，在1993~1998年期间为22%，在1999~2004年期间为22%，在2005~2010年期间为19%。43%的再住院与心脏病发作或其治疗相关，30%与此无关，27%与此的关系不明。再住院的最常见原因为缺血性心脏病(15%)、呼吸系统或其他胸部症状(10%)、心力衰竭(9%)和心律失常(6%)。其他原因包括手术并发症(92%)；液体/电解质问题(2%)；以及低血压、肺炎、栓塞/血栓形成、卒中或短暂性脑缺血发作(各1%)。

在再住院的患者中，有24%进行血管造影，9%进行PCI。其中25%对相同血管进行再次PCI。在再住院的患者中，44例进行CABG手术。在进行血运重建的患者中，45%在首次住院期间曾接受药物治疗。

一些治疗导致30天再住院风险显著增加，主要是由手术并发症引起：
•血管造影伴并发症：危险比(HR)，2.40。
•再灌注及血运重建，伴并发症：HR，2.12。

一些内科合并症也与再住院显著相关：
• 糖尿病：HR，1.34。
• 慢性阻塞性肺病(COPD)：HR，1.43。
• 心力衰竭：HR，1.12。

与既往有关奥姆斯特德县心力衰竭后再住院的报告相比，COPD、糖尿病和贫血是MI和心力衰竭患者再住院的常见危险因素。这些危险因素对于未来有关预防心血管疾病住院患者再住院的研究可能具有特别重要的意义。

该研究获美国国立卫生研究院资助。研究者声明无经济利益冲突。

爱思唯尔  版权所有

By: MICHELE G. SULLIVAN, Cardiology News Digital Network

Despite advances in the treatment of acute myocardial infarction, 30-day rehospitalization rates remained fairly constant from 1987 to 2010.

Rehospitalizations ranged from a high of 23% in 1987 to a low of 19% in 2010 – but that difference was not statistically significant, Dr. Shannon Dunlay and her colleagues reported in the July 3 issue of Annals of Internal Medicine

During that period, treatment advances were obvious. There was a significant decrease in fibrinolysis and significant increases in angiography, reperfusion, and percutaneous coronary intervention (PCI). But those improvements didn’t affect 30-day readmission rates, and in fact, seem to be a driver of them, the researchers, led by Dr. Dunlay, a cardiology fellow at the Mayo Clinic, Rochester, Minn., wrote.

"Angiography, reperfusion, and revascularization are mainstays of therapy in acute MI, and complications are associated with a high risk for rehospitalization," they wrote.

They also noted that "as the prevalence of such comorbid conditions as diabetes and COPD [chronic obstructive pulmonary disease] increases over time, rehospitalizations after acute MI may continue to shift toward noncardiovascular causes." Other medical comorbidities, including hypertension, hyperlipidemia, and obesity, were also significantly associated with readmission rates (Ann. Intern. Med. 2012; 157:11-18).

The authors found that 43% of the readmissions were related to the incident heart attack or its treatment, 30% were unrelated, and a relationship was unclear in 27%.

The review encompassed 3,010 cases extracted from the Rochester Epidemiology Project, a database that links patient records from three facilities in Olmstead County, Minn. The patients’ mean age was 67 years and did not change over the study period.

In-hospital survival improved over time (89% in 1987 and 96% in 2010).

There were significant changes in comorbid conditions from 1987 to 2010, including hypertension (61%-69%), hyperlipidemia (50%-68%), diabetes (22%-24%), and obesity [a body mass index of at least 30 kg/m2] (33%-38%).

Treatment changes included a significant decrease in fibrinolysis (28%-1%), and significant increases in reperfusion/revascularization (64%-69%), PCI (51%-63%), and angiography (76%-85%). The median length of stay dropped from 5 days to 3 days – also a significant change.

Increasing rates of complications were associated with these changes in treatment, the records showed. Ten percent of patients who underwent PCI had a complication. These included vascular or bleeding complications (6%), stroke (0.3%), and renal failure (5%). Of the vascular or bleeding complications, 63% were access site complications, most of which were groin hematomas.

The complication rate was low among patient receiving fibrinolysis (2%). Two percent of patients who had a coronary artery bypass graft (CABG) procedure had an associated stroke. The complication rate was 8% among patients who had angiography, with or without reperfusion. Most of those (5%) had acute renal failure, with three patients requiring dialysis. The other patients had vascular or bleeding complications.

Thirty-day rehospitalizations were required in 561 patients (19%), who were admitted a total of 643 times – 484 patients were admitted once, 72 twice, and 5 three times. Three percent (87) of the patients died within 30 days; among these, 19 were in a readmission when they died.

Readmission rates were 23% from 1987 to 1992; 22% from 1993 to 1998; 22% from 1999 to 2004; and 19% from 2005 to 2010.

The most common reasons for rehospitalization were ischemic heart disease (15%), respiratory or other chest symptoms (10%), heart failure (9%), and cardiac arrhythmias (6%). Other reasons included procedural complications (92%); fluid/electrolyte problems (2%); and hypotension, pneumonia, embolism/thrombosis, and stroke or transient ischemic attack (about 1%) each.

Angiography was performed in 24% of readmissions and PCI in 9%. Of these, 25% were repeat PCIs of the same vessel.

There were 44 CABG procedures among the readmitted group (28 planned). Forty-five percent of those undergoing a revascularization had been treated medically during their initial hospitalization.

Some treatments significantly increased the risk of 30-day readmission; most of that association was driven by procedural complications:

• Angiography with complications: hazard ratio, 2.40.
• Reperfusions with revascularization, with complications: HR, 2.12.

Some medical comorbidities also showed significant associations with readmission:

• Diabetes: HR, 1.34.
• Chronic obstructive pulmonary disease: HR, 1.43.
• Heart failure: HR, 1.12.

"Compared with our previous report on rehospitalizations after incident heart failure diagnosis in Olmsted County, COPD, diabetes, and anemia were common risk factors for rehospitalization among patients with incident MI and heart failure," the authors said. These risk factors "may be of particular importance as future targets in preventing rehospitalizations in patients hospitalized with cardiovascular disease."

The National Institutes of Health sponsored the study. The researchers reported having no relevant financial conflicts of interests.