Slightly more than 1 in 10 acute MI patients younger than 65 years old are readmitted within 30 days after discharge, according to a registry study published online June 17, 2015, ahead of print in Circulation. Even when accounting for possible confounders, women are a relative 22% more likely to return to the hospital than men. 

“[I]dentifying patients at a higher risk for rehospitalization [within 30 days of discharge] provides opportunities to develop interventions to reduce readmissions that are appropriate for an individual’s risk of readmission,” Rachel P. Dreyer, PhD, of Yale-New Haven Hospital (New Haven, CT), and colleagues write.

The researchers examined data from the Healthcare Cost and Utilization Project’s State Inpatient Database for California on 40,851 patients younger than 65 years old whose primary diagnosis was acute MI between January 2007 and November 2009.

In all, there were 42,518 index admissions, of which 26.4% involved women. The vast majority of patients (96.5%) had only one index admission during the study period.

Women were older (mean age 55 vs 54 years) and more likely to have Medicare or Medicaid insurance and to be African American or Hispanic than men. Women also more often had cardiovascular risk factors and a multitude of comorbidities, as well as longer hospital stays.

Many Readmissions Not Due to Cardiac Causes

Within 30 days after discharge, 4,775 patients (11.2%)—including 1,736 women—were readmitted for any cause. Women were more than 1.5 times more likely than men to be readmitted (15.5% vs 9.7%; P < .001).

The higher likelihood of readmission for women was evident across different age groups (P < .0001 for all):

• 18-49 years: 14.9% vs 8.7% 
• 50-54 years: 14.2% vs 9.6% 
• 55-59 years: 15.7% vs 10.0% 
• 60-64 years: 16.5% vs 10.5% 

Overall, readmission rates were highest at 2 to 4 days after discharge, and 42% of all readmissions occurred during the first week. Both men and women were more likely to be admitted for a cardiac cause, though noncardiac diagnoses were also common (table 1).

After adjustment for sociodemographics, cardiovascular risk factors, comorbidities, length of stay, and discharge disposition, women still had a 22% higher risk of readmission than men. The adjusted analysis also confirmed that age did not modify the association between sex and readmission risk (P = .53). 

Further adjustment for a secondary diagnosis of heart failure during the index admission and for multiple admissions in a single patient yielded similar results to the main analysis.

Furthermore, following readmission, women were less likely than men to undergo cardiac catheterization and PCI (P < .0001 for both), but both sexes were equally as likely to receive CABG (P = .06).

Multiple Theories to Explain Disparity

The study authors cite several possible reasons as to why readmission rates are higher for women than for men:

• Women tend to have more complications after acute MI, such as longer lengths of stay and bleeding events 
• Women may be more susceptible to the disruption of hospitalization itself and have more stressful and difficult experiences than men 
• Psychosocial factors, such as depression, health status, social support, and stress levels, could influence readmission rates 
• Women may have more caregiving responsibilities at home and work, which can impede their ability to focus solely on their own recovery  

In a accompanying editorial, Itzhak Gabizon, MD, of Soroka Medical Center (Be’er Sheba, Israel), and Eva Lonn, MD, of Hamilton Health Sciences (Hamilton, Canada), add that gender bias in the management of acute MI patients, both in the care of cardiac and noncardiac conditions, could also contribute to the discrepancies. 

Cindy Grines, MD, of Detroit Medical Center (Detroit, MI), cited other sex-based differences. “Women seek medical attention more frequently than men in general,” she told TCTMD in an email, “Also, these women were more likely to be black and poor—two populations that [may tend to] use the emergency room instead of seeing a primary care doctor.” Additionally, she said, women “have more chest pain despite less coronary disease” as well as more congestive heart failure due to diastolic dysfunction.

“Although the authors tried to control for these variables, it is not precise,” she stressed.

‘Posthospital Syndrome’ Frequent

The editorialists highlight the so-called posthospital syndrome, a term referring to the “particularly vulnerable period early postdischarge” when patients are at risk of rehospitalization. The current study, they say, demonstrates that the syndrome is suffered by younger patients, not just those who are older, and that younger women are at particularly high risk.

“I think the important thing to point out is that 40% of readmissions are noncardiac,” Dr. Grines stated. “This means the doctors should think beyond the heart when considering discharge after acute MI.”

“[I]n an era of ‘performance measures’ and increasing pressure to decrease hospital [length of stay]… cardiologists and cardiac teams are reminded that the care of patients with acute cardiac conditions needs to extend beyond the revolving doors of the coronary care unit and the catheterization laboratory,” Drs. Gabizon and Lonn write.

Good care, they continue, “entails many other aspects, such as careful discharge planning; utilizing a holistic approach, which addresses the disease underlying the acute index hospitalization but also other comorbidities; social supports; access to prompt medical attention and education [after] discharge; and the psychological stress associated with hospitalizations for acute medical conditions.”

1. Dreyer RP, Ranasinghe I, Wang Y, et al. Sex differences in the rate, timing and principal diagnoses of 30-day readmissions in younger patients with acute myocardial infarction. Circulation. 2015;Epub ahead of print. 
2. Gabizon I, Lonn E. Young women with acute myocardial infarction and the post-hospital syndrome [editorial]. Circulation. 2015;Epub ahead of print  

Disclosures:

• Drs. Dreyer, Gabizon, Lonn, and Grines report no relevant conflicts of interest. 

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