When patients present to the hospital with STEMI, early reperfusion with PCI or thrombolytic therapy is often offered as initial treatment. Over the last decade, several regional and national initiatives have been launched to facilitate and improve systems of care for STEMI. “These initiatives have enhanced the recognition of STEMI, reduced time to treatment, and increased survival,” says George A. Stouffer, MD. They have also improved systems of care and have facilitated patient access to PCI-capable facilities.
As a result of recent STEMI initiatives, national door-to-balloon times have improved significantly throughout the United States. However, most of these initiatives have focused solely on patients who develop STEMI outside the hospital setting, according to Dr. Stouffer. “We have very little information about the incidence and outcomes of inpatient-onset STEMI,” he says. He notes that large national databases that are aimed to improve quality of care exclude patients who develop STEMI when they are already hospitalized.
A Large Data Analysis
Recent research suggests that patients who develop inpatient-onset STEMI tend to be older, have more comorbidities, and are less likely to survive than patients with an outpatient STEMI. Dr. Stouffer and colleagues published a study in JAMA that aimed to better define the incidence and outcomes of inpatient-onset STEMI for conditions other than acute coronary syndromes (ACS). It also sought to identify variables that may be potential targets for strategies to improve processes and systems of care for these patients.
The investigators analyzed data from the California State Inpatient Database, which included over 62,000 STEMI patients who were treated in more than 300 of the state’s hospitals from 2008 to 2011. STEMIs were classified as inpatient onset or outpatient onset based on present-on-admission codes. Patients who had a STEMI after being hospitalized for suspected ACS were excluded from the analysis. “Our study is the largest to be performed on patients who have a STEMI while they’re in the hospital for a non-ACS condition,” Dr. Stouffer says.
According to the findings, nearly 5% of STEMI cases occurred in patients hospitalized for non-ACS indications. “Patients with inpatient-onset STEMI had higher in-hospital mortality rates, were less likely to be discharged home, and were less likely to undergo cardiac catheterization when compared with outpatient-onset STEMI,” says Dr. Stouffer. “Overall, patients developing inpatient-onset STEMI were three times more likely to die in the hospital than those with outpatient-onset STEMI.”
The study also showed that length of stay and inpatient charges were higher for inpatient-onset STEMI (Table 1). “Patients with inpatient-onset STEMI tended to be older and were more frequently female than those with outpatient-onset STEMI,” Dr. Stouffer adds. The authors looked at variables associated with outcomes of patients developing STEMI while they were hospitalized for a non-ACS condition and found that those who underwent any surgical procedure as part of their hospitalization had a higher risk of inpatient-onset STEMI (Table 2). The risk of inpatient-onset STEMI was lowest in patients with no procedures and highest in patients undergoing cardiac surgical procedures.
There are several possible reasons for mortality rates being higher in patients who have a STEMI while in the hospital, according to Dr. Stouffer. “These patients are older, have more comorbidities, and are less likely to have PCI than patients who have a STEMI outside the hospital,” he says. “Importantly, our study showed that the use of PCI was associated with a lower mortality rate, even in the highest-risk patients. This finding—along with earlier observations indicating that STEMI recognition in hospitalized patients is often delayed—suggests that targeted interventions focusing on these areas may improve outcomes.”
More Data Needed
Dr. Stouffer says that more research is needed to establish optimal approaches to treating hospitalized patients who experience a STEMI. “This is an area that merits more attention and concern because we have few data available,” he says. “We need regional or national databases that collect information on process measures regarding the management of inpatient-onset STEMI. We also need to develop a reporting infrastructure, either through existing databases or with new programs, in order to enhance our understanding of inpatient-onset STEMI.”
Although studies have identified several risk factors that appear to be associated with inpatient-onset STEMI, Dr. Stouffer says more data are needed to better define these factors. “Traditional ACS risk factors tend to be more common among those with inpatient-onset STEMI, but other potential factors also should be explored,” he says. “As we gather this data in the future, we will better understand the role that comorbidities and other factors play in inpatient-onset STEMI. This will then enable us to find ways to reduce this risk.”
Kaul P, Federspiel JJ, Dai X, et al. Association of inpatient vs outpatient onset of ST-elevation myocardial infarction with treatment and clinical outcomes. JAMA. 2014;312:1999-2007. Available at: http://jama.jamanetwork.com/article.aspx?articleid=1935123.
Dai X, Bumgarne Jr, Spangler A, Meredith D, Smith SC, Stouffer GA. Acute ST‐elevation myocardial infarction in patients hospitalized for noncardiac conditions. J Am Heart Assoc. 2013;2:e000004. Available at http://www.jaha.ahajournals.org/content/2/2/e000004.short.
Garberich RF, Traverse JH, Claussen MT, et al. ST-elevation myocardial infarction diagnosed after hospital admission. Circulation. 2014;129:1225-1232.
Maynard C, Lowy E, Rumsfeld J, et al. The prevalence and outcomes of in-hospital acute myocardial infarction in the Department of Veterans Affairs Health System. Arch Intern Med. 2006;166:1410-1416.
Jacobs AK, Antman EM, Faxon DP, Gregory T, Solis P. Development of systems of care for ST-elevation myocardial infarction patients: executive summary. Circulation. 2007;116:217-230.