In-Hospital STEMI Deadlier, More Expensive Than Out-of-Hospital STEMI
Patients who have an ST-segment elevation myocardial infarction (STEMI) while already hospitalized are 3 times more likely to die during their stay than those who have a STEMI outside of the hospital, according to a retrospective, multicenter study published in the November 19, 2014, issue of the Journal of the American Medical Association.
George A. Stouffer, MD, of the University of North Carolina School of Medicine (Chapel Hill, NC), and colleagues analyzed information from the California State Inpatient Database on 62,021 STEMI patients treated at 303 hospitals from 2008 to 2011. Nearly 5% of patients (n = 3,068) were already hospitalized for a non-ACS condition at the time of STEMI onset and 95.1% (n = 58,953) were not.
Patients with inpatient occurrence of STEMI were older (71.5 vs 64.9 years; P < .001) and more often female and had more comorbidities than those with outpatient-onset STEMI. But they were less likely to have diabetes without complications.
Poor Outcomes Unrelated to Baseline Differences
On multivariate adjustment, patients who had an in-hospital STEMI were over 3 times more likely to die during their hospital stay, were less likely to be discharged home and to undergo cardiac catheterization or PCI, and had increased length of stay and hospital costs (table 1).
aOdds ratios for death, discharge home, catheterization, and PCI; multiplicative effect for length of stay and hospital charges.
Among patients who developed STEMI during hospitalization, the use of cardiac catheterization and PCI decreased along with higher predicted risk of in-hospital mortality. Survival, however, improved with PCI use across all levels of risk, with the greatest benefit seen among patients most likely to die in-hospital (P = .003).
Several factors predicted inpatient-onset STEMI. After adjustment, patients who received any form of surgery during hospital admission were more likely to experience inpatient-onset STEMI than those who did not (OR 2.36; 95% CI 2.17-2.58); the highest risk was associated with cardiac surgical procedures. Nearly half of all in-hospital STEMIs (49.6%) followed surgery. Other characteristics, including congestive heart failure, metastatic cancer, weight loss, coagulopathy, valvular disease, and peripheral vascular disease were all associated with STEMI during hospitalization.
Treatment facility size did not have an effect on occurrences of in-hospital STEMI (P = .63).
Study Confirms Smaller Trial Results
Dr. Stouffer and colleagues say the current outcomes are in line with those of smaller studies; for example, in-hospital mortality was 2 times higher with inpatient-onset STEMI in a substudy of MITRA and 9 times higher in a recent single-center study.
The mortality increase could be partially due to a lack of invasive procedures, the authors write, because “data from outpatient-onset STEMI show that reperfusion in general and primary PCI in particular improves outcomes.”
In a telephone interview with TCTMD, Dr. Stouffer said that there are 4 major reasons to possibly explain the reduced use of such procedures seen here:
- Patients with in-hospital STEMI are more often female and older than those with outpatient STEMI
- They tend to have more comorbidities, including lung and kidney disease
- The condition for which they were originally hospitalized may hinder reperfusion
- Lack of data on who in this subgroup may benefit from reperfusion
That mortality rates dropped with use of PCI and cardiac catheterization, even among patients in the highest-risk quartile, suggests that “in appropriately selected patients, PCI may be of benefit even among patients with comorbid conditions that increase their risk of mortality,” the authors state.
Quality Improvement Initiatives Centered on Outpatient-Onset MI
Recognition of STEMI, the process of obtaining and interpreting an ECG, and the decision about treatment all tend to be delayed for in-hospital onset. Therefore, the study authors say, shortening time to reperfusion and increasing its use are both key to improving outcomes.
At this point, however, Dr. Stouffer said that the larger databases “explicitly exclude inpatient STEMI” and tend to focus on outpatient quality measurements such as door-to-balloon time. Because improvements have been made in that category, he continued, the cardiology community should apply the same methodology to inpatient-onset STEMI, starting with data collection.
Though data do not yet exist to prove the efficacy of this type of program, Dr. Stouffer said that his institution has adopted an initiative to help shorten the delays by collecting data on all inpatient STEMIs, placing learning modules explaining signs and symptoms of the condition on noncardiology floors for nurses, and having all ECGs with automated STEMI readings transmitted to cardiology fellows. His center also created a “cardiac response team” that is called for the incidence of inpatient STEMI, he explained, adding that a multicenter trial considering these programs is in the works.
“Inpatient STEMIs are a different animal… than outpatient STEMIs,” Dr. Stouffer said, noting that he and his colleagues found increased risk of inpatient STEMI in patients with metastatic cancer, weight loss, and other characteristics not necessarily attributed to the development of MI. “So, I think that it is not necessarily the typical plaque rupture that we think of with outpatient STEMI. It might be a different type of physiology, but we don’t really know at this point.”
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.
- Dr. Stouffer reports no relevant conflicts of interest.