Identifying those at risk of stroke

The British Heart Foundation estimates that excess deaths from stroke and other CVDs have reached 96,540 since February 2020, partly because the pandemic disrupted hypertension management. 

Each year, there are 100,000 strokes in the UK, which kill about 38,000 people – about one death every 15 minutes. Many of the 1.3 million stroke survivors live with disability. Tragically, 85 per cent of strokes may be preventable.¹

Immediate benefits

Quitting smoking, for example, dramatically reduces stroke risk. Blood pressure and pulse rate fall within 20 minutes of finishing a cigarette. According to the British Thoracic Society, a year after quitting, an ex-smoker’s increased risk of myocardial infarction (MI) and stroke declines to half that of a current smoker. Five to 15 years after quitting, an ex-smoker’s stroke risk reaches that of a non-smoker. 

Controlling hypertension also reduces stroke risk. A meta-analysis of 344,716 people from 48 studies estimated that a 5mmHg reduction in systolic blood pressure lowered the risk of stroke, MI and other major cardiovascular events by 9 and 11 per cent in those without and with previously diagnosed cardiovascular disease (CVD) respectively.²

According to NHS England, 2 million fewer people had recorded controlled hypertension in 2021 compared with 2020. Hypertension screening by pharmacists can help identify people who slipped between the Covid cracks.

Predisposing factors

Numerous factors predispose to stroke. A recent Danish study enrolled 179,680 women and 40,757 men with migraine. The median age was 41.5 and 40.3 years respectively. During a median 8.8 year follow-up, migraine increased the risk of ischaemic stroke among women and men by 21 and 23 per cent respectively compared with controls without migraine. 

In women, migraine increased the risk of MI and haemorrhagic stroke by 22 and 13 per cent respectively. In men, these differences were not statistically significant. The absolute increases in risk were low (0.1-0.5 per cent).³ 

Strokes are, however, most common in the UK between the ages of 70-79 years in men and 80-89 years in women. About a third of cases strike in people aged 40-69 years.

Inflammatory bowel disease (IBD) also increases stroke risk, even 25 years after a gastrointestinal diagnosis. A Swedish analysis matched 85,006 IBD patients and 406,987 controls. After a median follow-up of about 12 years, the adjusted stroke risk was 13 per cent higher in IBD patients compared with controls. The risk was 14 per cent higher for ischaemic stroke.⁴

The adjusted risk of ischaemic stroke was 19 per cent higher in people with Crohn’s disease, 9 per cent higher in those with ulcerative colitis and 22 per cent higher for unclassified IBD. 

The cumulative effect of the increased risk meant that after 25 years there was one additional stroke for every 79 people with Crohn’s disease, 156 with ulcerative colitis and 74 with unclassified IBD.⁴ 

Several mechanisms may underlie this increased risk, including changes in the gut microbiota that affect the brain, chronic systemic inflammation and prothrombotic factors that are particularly common among IBD patients (e.g. surgery, immobilisation due to fracture and steroids).⁴

Early warnings

Other warnings may emerge years before. For example, stroke patients show steeper declines in cognition and daily functioning up to 10 years before their first stroke, according to a recent Dutch study. 

During a mean follow-up of 12.5 years, 1,662 people had their first stroke. The analysis matched each stroke patient with three controls.⁵ Depending on the test, significant differences from controls emerged between 6.4 years (Mini-Mental State Examination) and 2.2 years (Basic Activities of Daily Living scale) before the stroke. The declines were especially marked in women, those carrying the gene APOEε4 (also linked with Alzheimer’s disease) and people with a lower educational level. 

The findings suggest that “accumulating intracerebral pathology before the acute event [stroke] already has a clinical impact, allowing for the identification of high risk individuals”.⁵

Identifying groups based on concurrent diseases and cognitive patterns allows more frequent screening of high-risk patients. Nevertheless, many people are at increased risk because of poorly controlled blood pressure, smoking and other lifestyle factors. 

Pharmacy teams can help pick up the post-pandemic pieces and, these days as part of their routine practice, reduce the number of people that experience this potentially disabling and all-too-often deadly disease.