Implantable heart defibrillators have similar survival benefits in everyday use as they do in clinical trials, a recent study shows.

Researchers at the Duke Clinical Research Institute compared data from more than 5,300 patients using defibrillators in the daily life to more than 1,500 patients using the device in clinical tests, and both groups showed similar two-year and three-year survival rates. The data was collected from a large Medicare registry that analyzed the survival rates of patients using implantable cardioverter-defibrillators, a device that prevents sudden cardiac arrest by reviving the heart if it stops beating. The results of the study highlight the real-world applicability of defibrillators.

The findings were published Jan. 2 in the Journal of the American Medical Association.

Patients in clinical trials generally receive better care and are healthier than patients in real-world practice, so the reported benefits of new drugs and medical devices are often more positive than actual results. The inflated expectations do not apply to defibrillators however, since the study indicates that the ICDs used in real life match clinical trial expectations.

“Many people question how the results of clinical trials apply to patients in routine practice,” said Dr. Sana Al-Khatib, a member of the Duke Clinical Research Institute and lead author of the study, in a press release. “We showed that patients in real-world practice who receive a defibrillator but who are most likely not monitored at the same level provided in clinical trials have similar survival outcomes compared to patients who received a defibrillator in the clinical trials.”

The patients used in the study were carefully selected to resemble the patients who participated in the clinical trials. Real-world users of ICDs showed higher survival rates than patients in the clinical trials who did not receive the defibrillator.

One limitation of the study it excluded older or sicker Medicare patients. By doing so, the researchers were not able to determine the entire scope of how real-world patients compare to clinical trial patients.

“That is an issue, and the only way to get at that is to randomly assign such patients to either receive an ICD or not in a clinical trial,” Al-Khatib noted. “Even without those data however, our study gives patients and their health care providers reassurance that what we have been doing in clinical practice has been helpful, and is improving patient outcomes. Our findings support the continued use of this life-saving therapy in clinical practice.”