No Gains Seen for ICDs Put in During Acute Hospitalizations in HF

BOSTON, MA — The benefits of implantable cardioverter defibrillator (ICD) therapy previously demonstrated in ambulatory patients with heart failure do not appear to apply to elderly patients who receive the device during hospitalization for exacerbation of heart failure or other acute comorbidities, an analysis of real-world effectiveness of ICDs suggests^[1].

"We specifically evaluated an elderly population with a high burden of comorbidities who had been hospitalized for heart failure or other acute comorbidities, and in these patients, an apparent difference in survival with ICDs is no longer evident when adjusted for potential confounding and healthy-candidate bias," Dr Soko Setoguchi (Duke Clinical Research Institute, Durham, NC) told heartwire from Medscape in written correspondence.

"This means that these elderly heart-failure patients are at greater risk of nonarrhythmic death during and after their acute hospitalization, and we therefore recommend that providers consider delaying the decision to implant a primary ICD until the patient has been discharged and can be reevaluated in the outpatient setting."

The study was published online July 14, 2015 in the BMJ.

Under lead author Dr Chih-Ying Chen (Harvard Medical School, Boston, MA), investigators carried out a retrospective cohort study using the ICD registry of the Centers for Medicare and Medicaid Services and the ICD registry of the American College of Cardiology-National Cardiovascular Data Registry.

The study population included 23,111 patients ≥66 years with heart failure with and without ICDs who had acute hospital admissions for heart failure or any comorbidities and who were considered eligible for ICD therapy for primary prevention.

Of these patients, 5258 had an ICD and 17,853 did not.

"For over 90% of the patients, the diagnosis that led to the index admission was heart failure or other cardiac causes," the authors observe.

During an average follow-up of 2.8 years, 53% of the cohort died.

The crude mortality rate at 1 year was lower for ICD recipients, at 18%, compared with 39% for eligible patients without an ICD as well as at 3 years, at 40% of ICD recipients compared with 60% for patients without an ICD.

However, as investigators point out, the crude mortality rates at 1 year in these Medicare hospitalized patients with an ICD were actually similar to mortality rates seen at 3 years in clinical trials of ICDs in ambulatory recipients.

Moreover, after adjustment for a variety of confounders, including a healthy-candidate bias, patients who received an ICD during an acute admission for heart failure or other comorbidities did not have a substantially lower risk of mortality (hazard ratio [HR] 0.91, 95% CI 0.82–1.00) or sudden cardiac death (HR 0.95, 95% CI 0.78–1.17) than those who did not receive an ICD.

A healthy-candidate bias is a type of selection bias that could arise when patients at high risk for complications or who are too sick to benefit from an ICD are not selected for one or when patients are not interested in preventing sudden death because of the burden of other chronic illness.

Evaluation of the effectiveness of ICDs without taking into account the healthy-candidate effect could overestimate its benefit, as the authors point out.

Researchers also found no significant difference in the effectiveness of ICDs among most demographic subgroups with the exception of a small group of patients over the age of 81.

Among these older patients, ICD use was associated with a 22% lower mortality risk (HR 0.78, 95% CI 0.65–0.93), although ICD use in the same small subgroup was not associated with a significant reduction in the risk of sudden cardiac death.

Similarly, among patients with an old MI, ICD therapy was associated with a 37% lower risk of mortality (HR 0.63, 95% CI 0.45–0.86), but again, a nonsignificant 26% reduction in sudden cardiac death.

ICD use was also associated with a 36% lower risk of death (95% CI 0.34–1.17) and a 49% lower risk of sudden cardiac death (95% CI 0.16–1.61) among patients with left bundle branch block, although the confidence intervals were wide, as investigators point out.

"We wanted to evaluate the 'real-world' effectiveness of ICDs because clinical-trial evidence may not directly apply to our study population, older heart-failure patients with a high comorbidity burden," Setoguchi observed.

Setoguchi added, however, that their findings do not apply to older patients who undergo ICD implantation during elective admissions or as outpatients. Approximately 40% of primary ICDs are currently implanted during acute hospitalizations.

This project is funded by the US Agency for Healthcare Research and Quality and the Centers for Medicare and Medicaid Services. Setoguchi reported receiving research support from Johnson & Johnson and receiving personal income for consulting from Sanofi. Disclosures for the coauthors are listed in the article.

Heartwire from Medscape © 2015  Medscape, LLC

Cite this: No Gains Seen for ICDs Put in During Acute Hospitalizations in HF - Medscape - Jul 31, 2015.