HRJ: Demographics, practice type affect ICD implantation decisions

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The use of implantable cardioverter-defibrillators (ICD) for sudden death prophylaxis across cardiology practices varies due to patient demographics, health conditions, geographic locations and practice types, based on a substudy on the IMPROVE-HF registry data published in the December issue of the HeartRhythm Journal.

Mandeep R. Mehra, MD, of the University of Maryland Medical Center in Baltimore, and colleagues assessed ICD use factors and guideline recommendations, as well as cardiac resynchronization therapy with defibrillator (CRT-D) in patients.

According to the authors, while national guidelines recommend ICD placement for patients with heart failure (HF) and left ventricular systolic dysfunction (LVSD), the authors said that little data examining the ICD treatment rates for these patients exist.

During the study, data was drawn from 15,381 patient records from 167 outpatient cardiology practices. A total of 7,221 patients met a Class I indication for ICD/CRT-D implantation. Of those 7,221 patients, 3,659 had implanted devices, 64 percent with an ICD and 36 percent with CRT-D. Forty-nine percent of the ICD/CRT-D eligible patients did not receive device therapy.

The average age of patients who were implanted with an ICD was 68 years, and men were more likely to receive (75 percent) than not to receive (66 percent) an ICD, according to the researchers.

In addition, the authors examined subgroups of patients “who might have been considered better candidates for this intervention based on age or the absence of certain comorbid conditions.” The results indicated that “younger patient age, white race and male sex were associated with higher rates of ICD therapy.”

Only 10 percent of the patients implanted with the devices were black, while 47 percent of those implanted with ICDs were white. However, race was not documented or missing in 41 percent of the cases.

Results found that ICD usage was most prevalent in the northeast with 57 percent of patients implanted with a device, compared to the west, south and central at 39, 49 and 52 percent, respectively.

In regards to hospital settings, patients treated in a university practice setting were most likely (54 percent) to be implanted with an ICD device, compared to 52 percent treated in a non-university teaching setting and 50 percent treated at a non-university, non-teaching setting.

Results also showed that a higher number of cardiologists and electrophysiologists were more likely to treat patients with ICD therapy. In addition, researchers found that eligible patients with a history of atrial fibrillation or coronary artery bypass graft procedures also had higher rates of ICD usage.

According to the authors, “ICD devices are potentially underutilized in patients with HF, with 49.3 percent of eligible patients not receiving ICD therapy in outpatient cardiology practices.”

The researchers said that the under-utilization of ICDs is due to “differences between the demographic and clinical characteristics of patients with HF encountered in the real world of clinical care compared with participants in randomized controlled trials.”

Based on the results, the authors wrote, “This study provides additional confirmation that certain patient characteristics, such as female sex, black race, and older age, were associated with lower use of ICD therapy for eligible patients after statistical adjustment for other factors.”

Because IMPROVE HF represents "self-selected practices willing to participate in a quality improvement initiative," the authors noted that these study findings may overestimate ICD usage in eligible patients.