Patients discharged from one hospital then readmitted to a different hospital are more likely to die than patients readmitted to their original hospital, according to a new study in CMAJ Open.

About one in five patients readmitted to a hospital within 30 days of discharge spend their first visit in one hospital and the second in a different ("alternative") institution.

"Our experience suggests that readmitting an unfamiliar patient is particularly challenging," says lead author Dr. John A. Staples, "We wanted to determine if this discontinuity of care affected patient outcomes."

To examine this question, Dr. Staples and colleagues from the Institute for Clinical Evaluative Sciences, (ICES), Toronto, Ontario, assembled a cohort of about 200 000 patients readmitted to one of 21 acute-care hospitals in Canada's largest urban area. Patients undergoing alternative-hospital readmission were more likely to die within 30 days than were patients undergoing original-hospital readmission (22% v. 19%). Patients undergoing alternative-hospital readmission also tended to be older and have more health problems. The increased mortality attenuated substantially but did not disappear after adjustment for these factors.

"One interpretation of these findings is that alternative-hospital readmission can compromise patient safety," says Dr. Staples. "Yet it's also possible that these findings reflect the greater burden of illness among alternative-hospital patients, particularly if that burden of illness wasn't fully captured in the databases we used."

The study highlights the frequency with which readmitted patients do not return to the hospital from which they were discharged, and further underscores the substantial risk of death among all readmitted patients. Regardless of the cause of increased mortality, the authors conclude that "alternative-hospital admissions are worrisome and merit attention."