Older people with comorbidities may not benefit from defibrillators

Older people with comorbidities and those with multiple hospital admissions related to heart failure are unlikely to receive a meaningful survival benefit from implanted defibrillators, found a study in CMAJ by researchers from Brigham and Women’s Hospital and Harvard Medical School in Boston, Massachusetts.

The cohort study looked at more than 14,000 patients with heart failure using an administrative database over 5 years. The mean age of the group was 77 years, and patients had a high level of comorbidities such as other cardiovascular disease, diabetes, chronic pulmonary disease and kidney disease.

Survival declined progressively after repeated hospital admissions and implantable defibrillators would have apparently extended life by just over 6 months. However, patients under 65 years of age and older patients without kidney disease, cancer or dementia would be most likely to benefit from implantable defibrillators to prevent sudden death.

"In contrast to our observations, information from the US National Cardiovascular Data Registry for 2006–2007 indicates that implantable defibrillators are frequently implanted in older patients with heart failure: 61% of patients were 65 years or older, and 15% were 80 years or older," write Dr Soko Setoguchi and co-authors. Fifty-eight percent of patients had previously been admitted to hospital and comorbidities were common.

The health and social burden of heart failure is significant, with 1.09 million related hospital admissions in the United States in 2003 and 106,130 admissions in Canada in 2001. Implantable defibrillators have shown benefit for people with heart failure in studies, but trials often exclude the elderly and patients with comorbidities.

"As Setoguchi and colleagues point out, patients at extremely high risk of death, including patients with prior (particularly multiple) heart failure hospitalisations and chronic kidney disease, have such a high risk of all-cause non-arrhythmic death that even if the 20% or so of potentially treatable sudden deaths were prevented, the overall risk of death would remain prohibitively high," writes Dr Paul Dorian from the University of Toronto and St. Michael’s Hospital, Toronto, in a related commentary.

(Source: Canadian Medical Association: Canadian Medical Association Journal: April 2009)