Mass-media advertising encourages people with stroke symptoms to go to hospital more quickly

Jun 1 2007

Mass-media advertising can encourage more people experiencing stroke symptoms to go to the hospital more quickly, according to a study published in Stroke: Journal of the American Heart Association.

After a Canadian public awareness campaign on stroke signs, more people presented at hospital emergency departments with stroke, and the effect was particularly striking for the type of stroke known as transient ischemic attack (TIA) or mini stroke, said Corinne Hodgson, M.A., M.Sc., lead investigator of the study and an Ontario-based consulting epidemiologist for the Heart and Stroke Foundation of Ontario. Because the warning signs of TIA are temporary, many people don't seek immediate medical attention, she said. Getting more people with TIAs to emergency departments is a critical opportunity for stroke prevention, because a TIA is often a precursor to a major stroke. The campaign was unique on three fronts. First, there was access to a registry of emergency room stroke visits. Second, the use of ongoing public polling research to track awareness over time and third, the convergence of corporate mass media campaign strategies and tactics utilized to communicate health promotion messages, said co-author Frank Rubini of the Heart and Stroke Foundation of Ontario.

The Heart and Stroke Foundation of Ontario conducted two province-wide television advertising campaigns on the warning signs of stroke, targeting adults age 45 and older. The first campaign ran from October 2003 to June 2004 and the second from December 2004 to July 2005. The Government of Ontario provided funds to air the campaign.

The ads featured the five warning signs of stroke with the word 'sudden overlaid sudden weakness, sudden trouble speaking, sudden vision problems, sudden severe headache, sudden dizziness. A voiceover encouraged viewers to call 9-1-1 or their local emergency number if they experienced any symptoms.

Researchers took a random telephone poll of 1,000 Ontarians age 45 and older to monitor awareness of the ad campaigns. The phone surveys included open-ended questions about stroke warning signs until five responses were received. Researchers conducted the surveys just before, during and right after the first campaign; during and in the weeks after the second campaign; and eight months after the second campaign. They surveyed different people each time.

To explore the effectiveness of the mass media campaigns on stroke awareness and treatment behaviors, researchers reviewed the Canadian Stroke Network's registry of emergency department visits for stroke during 31 months, ranging from several months before the campaign first ran, to several months after the second campaign ended. They then analyzed data on the number of patients who came in with stroke or TIA, including the total number of visits, how many came in within five hours of symptom onset, how many came in within two-and-a-half hours, and how many had a diagnosis of TIA. Researchers found a significant increase in the mean number of emergency department visits for stroke while the awareness campaign aired.

Over the 31 months, 12,534 visits for stroke were recorded, and 34.4 percent (4,303) of victims arrived within two-and-a-half hours of symptom onset and 48.1 percent (6,024) arrived within five hours. Of the total visits, 24.3 percent (3,040) were for TIAs. When the numbers were analyzed, almost 30 percent of the increase in emergency department visits for TIA is explained by whether a mass-media campaign was running, said Patrice Lindsay, Ph.D, a Performance and Standards Specialist with the Canadian Stroke Network.

The effect of the awareness campaign on stroke presentations to the emergency department was about a 10 percent increase overall, with a 15 percent increase for arriving at the hospital within five hours and a 5 percent increase for arriving within two-and-a-half hours.

From August 2003 to August 2005, researchers found a consistent increase in the proportion of people who correctly named two or more signs of stroke, as well as an increase in the average total number of warning signs correctly named. At the same time, the proportion of people who could not name any warning signs dropped from 21.7 percent in 2003 to 10.2 percent in 2005, Hodgson said. The study also found that after eight months of no advertising, the proportion of people who named two or more warning signs of stroke dropped from 72.7 percent to 63.6 percent. We suspect that television advertising may be more effective than some other media in reaching all subgroups of society, Hodgson said. However, for stroke awareness campaigns to be effective, they must be continuous. This finding reflects what has been demonstrated in other public health fields such as smoking prevention, but we think it is the first time it has been shown for stroke awareness. It has profound implications for the way we develop and implement stroke awareness initiatives.