In the month following an older heart patient's hospital discharge, there is a one in five risk of rehospitalization or death, but little is known about how these risks change over time.

Researchers at the Yale School of Medicine found that risks remain high for up to a year, but can be addressed with targeted care.

"If we can track absolute risks and their changes over time, this information will be critical in helping patients and hospitals set realistic expectations and goals for recovery, and plan for appropriate care after discharge," Kumar Dharmarajan, lead author of the study, said in a statement. "As our health system increasingly focuses on improving long-term health and personalizing care, this information can help hospitals focus their interventions during the highest risk periods for patients."

For the study, researchers looked at 3 million Medicare patients aged 65 or older who survived hospitalization for heart failure, acute myocardial infarction, and pneumonia from 2008 to 2010. The research team defined the absolute risks of rehospitalization and death on each day during the full year after discharge.

They found that risk of rehospitalization and death declined slowly following hospital discharge and remained elevated for many months. They also found that specific risks vary by discharge diagnosis and outcomes over time. For example, risk remains elevated for a longer period of time following hospitalization for heart failure compared with hospitalization for acute myocardial infarction and pneumonia. For all three conditions, risk of rehospitalization remains elevated for a longer period of time than risk of death.

"Patients should remain vigilant for deterioration in health for an extended time after hospitalization," Dharmarajan said. "This might mean checking in more often with a primary care physician or specialist."

In future studies, Dharmarajan and his team will seek to understand other factors that impact long-term risks, and how to integrate this information into more efficient and effective care plans.

The findings are detailed in the British Medical Journal.