The study, published in PLOS Medicine, looked at data from south London patients who had an ischemic stroke—one caused by a blood clot—between 2000 and 2015. The team attribute the reduced risk to improvements in care and medication.

After adjustments for population changes, the research showed that the risk of death from stroke fell by 24% over the 15 year period, with the 1-year death rate dropping from 32.6% in 2000 to 20.15% in 2015. The 1 year death rate is the incidence of death within 1 year of the stroke. The risk of disability after a stroke fell by 23%, from 34.7% in 2000 to 26.7% in 2015.

With around 52,000 people having ischemic strokes nationwide each year, the team arrived at a figure of 6,300 more patients annually surviving their stroke for over a year, and 3,200 fewer patients each year have a disability as a result of a stroke.

Stroke is a serious condition that occurs when blood supply to part of the brain is cut off. Stroke is the fourth single leading cause of death in England and Wales, and the third biggest cause of death in Scotland and Northern Ireland, with almost 38,000 people dying as a result of stroke in the UK in 2016.

The researchers used data from the South London Stroke Register, which collected data from patients in Lambeth and Southwark. They looked particularly at data from the 3,128 patients who had an ischemic stroke. Previous analysis of the same source had shown that between 2000 and 2015 the rate of strokes in the area decreased by 43%, with the risk of death from stroke falling by 24%.

The paper showed that the risk of death and disability had reduced for all genders, and for both black and white patients.

"It's really positive news to see that for patients who do have a stroke, the risk of death and disability is decreasing. Alongside our previous work showing a reduction in the rate of strokes it shows that, although there is still more to do, trends are moving in the right direction," said author of the study Dr. Yanzhong Wang, reader in medical statistics at King's College London, School of Population Health and Environmental Sciences.

He continued, "We think the change is due to improvements to the way we treat stroke, such as higher admission rates to hospital, increased use of CT and MRI scans, and more frequent treatment with thrombolytic and anticoagulant medications in the acute phase of stroke. We also believe that a shift towards patients having less severe strokes, perhaps caused by improved public health, could also play a role in the change.

"We're really grateful to all the patients who have taken part in the South London Stroke Register. Their valuable input is giving us an incredibly detailed understanding of stroke rates, which can help us treat and prevent strokes in the future."

The South London Stroke Register has been looking at the number of strokes recorded among the 350,000 people in south London since 1995. The register uses data sources including anonymous data from A&E records and data collected by specially trained doctors, nurses and field workers.