A study appearing in JAMA detailed how more than 100,000 patients who received implantable cardioverter-defibrillators (ICDs) found that about 20 percent did not meet evidence-based guidelines for receipt, and that these patients had a significantly higher risk of in-hospital death than individuals who met criteria for receiving an ICD.

Several randomized controlled trials have shown the effectiveness of ICDs for preventing sudden cardiac death in patients with advanced systolic heart failure, but practice guidelines do not recommend use of an ICD for primary prevention in patients recovering from a heart attack or coronary artery bypass graft surgery, as well as those with severe heart failure symptoms or a recent diagnosis of heart failure. "The degree to which physicians in routine clinical practice follow these evidence-based recommendations is not clear," the authors write.

Sana M. Al-Khatib, M.D., M.H.S., of the Duke Clinical Research Institute, Durham, N.C., and colleagues conducted a study to determine the number, characteristics and in-hospital outcomes of patients who received a non-evidence-based ICD. The study included an analysis of cases submitted to the National Cardiovascular Data Registry-ICD Registry between January 2006 and June 2009.

The researchers found that of 111,707 initial primary prevention ICD implants that occurred during the study period, 22.5 percent were for a non-evidence-based indication. Of these, 36.8 percent were in patients within 40 days of a heart attack and 62.1 percent were in patients with newly diagnosed heart failure. The risk of in-hospital death was significantly higher in patients who received a non-evidence-based device than in patients who received an evidence-based device. The risk of any post-procedure complication was significantly higher in the non-evidence-based ICD group compared with the evidence-based group.

"Although the absolute difference in complications between the groups is modest, these complications could have significant effects on patients' quality of life and health care use, including length of hospital stay and costs. Importantly, these complications resulted from procedures that were not clearly indicated in the first place. While a small risk of complications is acceptable when a procedure has been shown to improve outcomes, no risk is acceptable if a procedure has no demonstrated benefit," the authors write.

Any adverse event and death were significantly higher in patients who received a non-evidence-based device. The median length of hospital stay was significantly longer for patients who received a non-evidence-based ICD compared with patients who received an evidence-based ICD. Also, there was substantial variation in non-evidence-based ICDs by site.

The proportion of ICD implants performed by the different types of physician specialty was 66.6 percent for electrophysiologists, 24.8 percent for non-electrophysiologist cardiologists, 2.6 percent for thoracic surgeons, and 6.1 percent for other specialists. The rate of non-evidence-based ICD implants was significantly lower for electrophysiologists (20.8 percent) than non-electrophysiologists (24.8 percent for non-electrophysiologist cardiologists; 36.1 percent for thoracic surgeons; and 24.9 percent for other specialties). There was no clear decrease in the rate of non-evidence-based ICDs over time.