Cardiovascular implantable electronic device-related infections linked with increased risk of death

(Press-News.org) CHICAGO – An association has been found between infection associated with cardiovascular implantable electronic devices (CIEDs) and increases in mortality and hospital care costs, according to a report published Online First by Archives of Internal Medicine, one of the JAMA/Archives journals. The article is part of the journal's Health Care Reform series.

Therapy with CIEDs, which include pacemakers, implantable cardioverter-defibrillators and cardiac resynchronization therapy/defibrillator devices, can reduce illness and death rates in appropriately selected patients, according to background information in the article. However, complications including infection may mitigate this benefit. "Although it is well recognized that the rate of CIED infection is increasing faster than the rate of CIED implantation, there are limited published data on the risk-adjusted mortality and cost associated with CIED infection or the relationship of these outcomes to different CIED types," write the authors.

Muhammad R. Sohail, M.D., from the Mayo Clinic College of Medicine, Rochester, Minn., and colleagues analyzed the risk-adjusted total and incremental admission mortality, long-term mortality, admission length of stay (LOS) and admission cost associated with infection. They used data from the 100% Medicare Standard Analytic File Limited Data set version for inpatient admissions. The study group consisted of 200,219 Medicare fee-for-service patients who were admitted for CIED generator implantation, replacement or revision between January and December 2007. The researchers used the Centers for Medicare & Medicaid Services' payment-rate calculation methods, and used factors to reflect the admitting hospital's location, teaching status and indigent care load in order to standardize charges.

Researchers found a total of 5,817 admissions with infection. Depending on the CIED type, infection was associated with significant increases in adjusted admission mortality (4.6 percent to 11.3 percent, depending on type of device) and long-term mortality (26.5 percent to 35.1 percent, depending on type of device). Approximately half of the incremental long-term mortality occurred after patients were discharged. Depending on CIED type, the adjusted LOS was significantly longer with infection. With infection, the standardized adjusted incremental and total admission costs were $14,360 to $16,498 and $28,676 to $53,349, depending on CIED type. Intensive care accounted for more than 40 percent of the incremental admission cost. When researchers adjusted long-term mortality rate and cost ratios with infection by CIED type, pacemakers were associated with significantly greater increases in both measures, compared with implantable cardioverter-defibrillators or cardiac resynchronization therapy/defibrillator devices.

"Our work demonstrates that Medicare beneficiary admissions for CIED procedures with infection are associated with significant, device-dependent, incremental increases in admission mortality and long-term mortality, LOS, and cost compared with those without infection," write the authors. "Intensive care and pharmacy services accounted for more than half of the incremental cost with infection and could be targeted to reduce costs associated with management of CIED infection. The etiology of excess mortality in patients with CIED infection after hospital discharge remains unclear and merits further investigation."

(Arch Intern Med. Published online September 12, 2011. doi:10.1001/archinternmed.2011.441. Available pre-embargo to the media at www.jamamedia.org.)

Editor's Note: TYRX Inc. provided salary support for Ms. Braid, Dr. Forbes and David J. Wright, Ph.D., as consultants, to assist with data collection (Ms. Braid), analyses (Ms. Braid and Dr. Forbes) and review (Dr. Wright). Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

Commentary: Cardiac Implantable Electronic Devices

In an accompanying commentary, Ronan Margey, M.D., M.R.C.P.I., from Massachusetts General Hospital and Harvard Medical School, Boston, describes the increase in both CIED use and of related infections. The author notes that in 2000, approximately 3.4 million people worldwide were living with a permanent CIED, and that new device implantations in the United States increased 49 percent between 1999 and 2003. Infection rates related to CIEDs also appear to have increased—in one Medicare analysis, a rise of 124 percent in proven CIED infection between 1990 and 1999 was found.

"There are significant cost implications for CIED infection, with the opportunity cost of having to remove a device and potentially implant a new one," writes Margey. The infections also exert a toll on health, according to the results from Sohail and colleagues' study. "It provides further evidence that patients who develop CIED infection have an ongoing poor prognosis, with more than half of the mortality occurring during follow-up," Margey points out.

"In the current era of appropriate resource utilization, the timely article by Sohail et al highlights the serious cost implications of CIED infection," Margey concludes. "It is a warning siren to physicians to be sure … implantation is appropriate per professional society guidelines and to monitor patients at risk of developing infection closely and intervene promptly."

### (Arch Intern Med. Published online September 12, 2011. doi:10.1001/archinternmed.2011.446. Available pre-embargo to the media at www.jamamedia.org.)

Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

To contact Muhammad R. Sohail, M.D., call Bob Nellis at 507-284-5005 or e-mail nellis.robert@mayo.edu. To contact commentary author Ronan Margey, M.D., M.R.C.P.I., call Ryan Donovan at 617-724-6433 or e-mail rcdonovan@partners.org.