Senior author Dr. Richard Swartz, a neurologist at Sunnybrook Health Sciences Centre in Ontario, Canada, and colleagues conducted the study. Their findings were published in CMAJ.
Stroke is the fifth leading cause of death in the United States, responsible for more than 130,000 deaths each year. More than 795,000 U.S. adults have a stroke each year, and around 185,000 of these affect individuals who have had a previous stroke.
According to some research, the risk of recurrent stroke accumulates early after an initial stroke or mini-stroke, or transient ischemic attack (TIA), and this is typically within the first 90 days. For this reason, the 90-day period after a stroke or TIA has been the focus of secondary prevention strategies in both research and clinical practice.
Population-based studies have shown that in addition to having high short-term risks, the risk of recurrent strokes and death remain elevated in the long-term, with an 18 percent and 44 percent estimated risk over the course of 5 and 10 years, respectively, after an initial stroke or TIA.
"There is a real need to maintain risk reduction strategies, medical support, and healthy lifestyle choices over the long-term, even years after a mild initial event," says Dr. Swartz.
While data are available for risk estimates of adverse outcomes during the early high-risk period, little data are available to characterize long-term risk in individuals who experience no early complications after stroke or TIA.
Dr. Swartz and team aimed to determine the long-term risks among patients who survived their initial ischemic stroke event and who experienced no further adverse events for 90 days after discharge from the emergency department or the hospital.
Stroke survival marker of long-term risk
The study included data from 26,366 patients who had been discharged from regional stroke centers in Ontario between July 2003 and March 2013, after having a stroke or TIA without complications in the first 90 days.
The cases were matched with 263,660 control participants - that is, those who have not experienced stroke - on age, sex, and geographical location.
The researchers found that the group who did not experience early complications had a significantly higher risk of long-term complications than the controls.
By 1 year past the initial event, 9.5 percent of post-stroke patients had experienced an adverse event such as another stroke, a heart attack, admission to long-term care, or death. The proportion of people who experienced adverse events increased to 23.6 percent at 3 years and 35.7 percent at 5 years.
"These findings highlight the need for long-term management of modifiable risks, such as high blood pressure, monitoring, and treatment of irregular heart rhythms, quitting smoking, and physical activity."
Dr. Richard Swartz
Long-term strategies for risk reduction could include cardiac rehabilitation programs that are tailored for stroke survivors to follow for years, as opposed to months, after their stroke event. Long-term management could also be embedded into primary care practices.
"For survivors of stroke or TIA, the long-term risk of recurrent stroke was particularly high, indicating that stroke recurrence is the most important modifiable outcome," conclude the researchers.