New Study Finds Few Medicare Patients Get Implantable Cardioverter Defibrillators Following Heart Attack

More than 350,000 people experience sudden cardiac death in the United States each year, yet fewer than 1 in 10 Medicare patients receives an implantable cardioverter-defibrillator (ICD) as a preventive measure following a heart attack, according to results of a new study published with an abstract in the June 23 issue of the Journal of the American Medical Association. In this large observational study, funded in part by AHRQ, a research team led by Duke University Medical Center sought to determine ICD implantation rates and associated mortality among patients 65 years and older with previous heart attack and low ejection fraction, a measure that determines how well the heart can pump blood. Evidence indicates that ICDs are underused in routine clinical practice, especially among older patients whose risks of heart attack and heart disease increase with age. Data for the study were drawn from 10,318 Medicare patients whose information was entered into a national cardiovascular registry and who were treated at 441 U.S. hospitals between 2007 and 2010. In addition to the low rate of ICD implantation among older patients, researchers also found that one-year ICD implantation was associated with significantly lower two-year mortality. Patients who had more contact with the health care system through early cardiology follow-up or readmission for heart attack or heart failure were more likely to undergo an ICD implantation, the study found. Further research is needed to determine evidence-based approaches to increase ICD implantation among eligible patients, researchers concluded.

2015 Jun 23-30;313(24):2433-40. doi: 10.1001/jama.2015.6409.

Implantable Cardioverter-Defibrillator Use Among Medicare Patients With Low Ejection Fraction After AcuteMyocardial Infarction.

Pokorney SD1, Miller AL2, Chen AY3, Thomas L3, Fonarow GC4, de Lemos JA5, Al-Khatib SM1, Peterson ED1, Wang TY1.

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Abstract

IMPORTANCE:

Implantable cardioverter-defibrillators (ICDs) are not recommended within 40 days of myocardial infarction (MI); thus, ICD implantation might not be considered during the post-MI care transition.

OBJECTIVE:

To examine ICD implantation rates and associated mortality among older MI patients with low ejection fraction (EF).

DESIGN, SETTING, AND PARTICIPANTS:

Retrospective observational study of Medicare beneficiaries with an EF of 35% or less after MI, treated at 441 US hospitals between 2007 and 2010, excluding patients with prior ICD implantation. Follow-up data were available through December 2010.

EXPOSURES:

ICD implantation within 1 year of MI vs no ICD implantation within 1 year of MI.

MAIN OUTCOMES AND MEASURES:

Patient characteristics associated with receiving an ICD within 1 year after discharge and 2-year mortality associated with ICD implantation.

RESULTS:

Among 10,318 MI patients with EF of 35%or lower, the cumulative 1-year ICD implantation rate was 8.1% (95%CI, 7.6%-8.7%). Patientswith ICD implantation were more likely to have prior coronary artery bypass graft procedures, higher peak troponin levels, in-hospital cardiogenic shock, and cardiology follow-up within 2 weeks after discharge relative to patients who did not receive an ICD within 1 year. Implantation of ICD was associated with lower 2-year mortality (15.3 events per 100 patient-years [128 deaths in 838 patient-years] vs 26.4 events per 100 patient-years [3033 deaths in 11 479 patient-years]; adjusted HR, 0.64; 95%CI, 0.53-0.78). [table: see text]

CONCLUSIONS AND RELEVANCE:

In this large registry study of older patients who experienced MI from 2007-2010, fewer than 1 in 10 eligiblepatients with low EF received an ICD within 1 year after MI, although ICD implantation was associated with lower risk-adjusted mortality at 2 years. Additional research is needed to determine evidence-based approaches to increase ICD implantation among eligible patients.