Thursday, January 28, 2016

Vasovagal syncope and driving

Vern Hsen Tan, Debbie Ritchie, Connor Maxey, Robert Sheldon.  Prospective Assessment of the Risk of Vasovagal Syncope During DrivingONLINE FIRST. JACCCEP. 2016;():. doi:10.1016/j.jacep.2015.10.006

Objectives This study sought to estimate the likelihood of a motor vehicle accident causing serious risk or harm in patients with frequent vasovagal syncope, and compare this with international accident data.
Background Recurrent vasovagal syncope poses a risk because of fainting while driving, but prospective, benchmarked estimates of this risk have not been reported.
Methods Data were from the POST (Prevention of Syncope Trial)-1 and -2, which were multicenter randomized studies of patients with ≥3 lifetime vasovagal syncope spells. POST-1 patients (reported in 2005) received metoprolol or placebo for ≤1 year between 1998 and 2004; POST 2 patients received fludrocortisone or placebo for ≤1 year between 2006 and 2011. Accident data were recovered from Internet reports from the United States, United Kingdom, and Canada.
Results A total of 418 patients (age 38 ± 17 years) had a median of 10 lifetime faints and a median of 3 faints in the previous year. Total follow-up time was 323 years, or 0.77 years per person. A total of 174 subjects fainted, having a total of 615 faints. Two patients fainted while driving, without fatality or injury, with a likelihood of 0.62% per person-year. The risk of serious harm or death was <0.0035% per person-year, and 0.0018% per faint. In the general U.S., U.K., and Canadian driving populations, the risk of serious harm or death was 0.067% per driver-year, and the risk of death was 0.009%.
Conclusions The estimated risk of serious harm or death was <0.0035% per person-year in highly symptomatic patients, less than the risk of serious harm or death in the general population. (A Randomized Clinical Trial of Fludrocortisone for Vasovagal Syncope: The Second Prevention of Syncope Trial [POST II]; NCT00118482)

Courtesy of:

In this largest analysis of this risk to date, Dr Vern Hsen Tan (University of Calgary, Alberta, and Changi General Hospital, Singapore) and colleagues analyzed data from 418 adults from the combined Prevention of Syncope (POST) 1 and POST 2 trials...

Based on case records, they found that during a mean follow-up of 0.77 years, two patients fainted while driving. One had a prodromal syndrome and pulled off to the side of the road, and the other had minor bodily injuries...

There are two takeaway messages for clinicians. First, "this at least gives some information on how to talk with a specific patient [with vasovagal syncope] about what their risk [of an accident while driving] is," he said. The study showed that "the likelihood of a motor-vehicle accident in patients with moderately frequent vasovagal syncope is very low and well within societal tolerance based on general motor-vehicle accident rates."

Second, despite this low risk, "You've got to know the law, [and clinicians] have to obey the law," which is very different in various US states and Canadian provinces, he said. For example, in Alberta, clinicians need to discuss driving limitations with patients with vasovagal syncope, whereas in Ontario, clinicians also have to inform authorities...

Vasovagal syncope is common and affects a third of men and more than 40% of women, according to Sheldon...

POST 1 randomized 208 individuals with vasovagal syncope who were seen from 1998 to 2003 in study centers mainly in Canada, but also Columbia, Germany, the US, and Australia to receive the beta-blocker metoprolol or placebo.

POST 2 randomized 210 similar individuals seen from 2006 to 2011 in study centers mainly in Canada, but also Columbia, the US, and Poland, to receive fludrocortisone or placebo. Neither therapy significantly reduced the risk of syncope during a follow-up of about a year.

They had fainted a median of 10 times in their lives including a median of three times in the year prior to enrollment...

During a mean follow-up of 0.77 years, 174 study participants had 615 fainting episodes, and two participants (one in POST 1 and one in POST 2) fainted while driving. Thus the likelihood of fainting while driving was 0.62% per person-year and the estimated risk of a serious injury or death caused by fainting while driving was <0.0035% per person-year.

Based on data for motor-vehicle accidents and casualties, the researchers estimate that in the general population in Canada, the US, and the UK, from 2009 to 2012, the risk of either serious harm or death from driving was 0.067% per driver-year, and the risk of death was 0.009%.

Tan and colleagues acknowledge several study limitations. POST 1 and POST 2 were not designed to evaluate syncope and driving, and on average, patients were followed for under a year. Moreover, very few patients were older than 70, so the results cannot be generalized to elderly drivers.
Importantly, they had no information about the advice about driving that clinicians gave these patients or whether the clinicians followed provincial or state guidelines for driving restrictions. However, in Alberta, where 170 of 418 patients lived, patients who faint are very rarely prohibited from driving for more than a week, according to the researchers. 
In addition, they had no information about patient compliance with advice they received about driving.

On the other hand, this was the largest reported patient cohort, and "the follow-up duration captures a reasonable horizon of clinical decision making," according to Tan and colleagues.
"Much larger and prospectively designed studies are required to provide more precise estimates of risk for policy makers," they urge.

No comments:

Post a Comment