Lengthy periods of ambulance diversion are associated with higher mortality rates among patients with time-sensitive conditions, such as acute myocardial infarction.

When a patient’s nearest emergency department was on diversion for 12 or more hours, there were higher patient mortality rates at 30 days, 90 days, nine months, and one year than when not on diversion, according to a new study in the June 15 issue of the Journal of the American Medical Association.

This study of nearly 14,000 elderly patients indicates that ambulance diversion is a signal of a larger access problem in the health care system. Study authors said that ambulance diversion affects not only the patients who are diverted, but also non-diverted patients within the hospital.