Older age, black ethnicity, and low earnings are linked to poor blood pressure control, according to an analysis of UK Biobank participants.
High blood pressure is controlled in only two out of five UK patients with the condition despite treatment, suggests new research led by Dr Neo Tapela from the Nuffield Department of Population Health and published today in Open Heart.
People who are older (60+), of black ethnicity, and who are on relatively low incomes (£18,000/year) are less likely to have well controlled blood pressure, the findings indicate.
High blood pressure is the leading preventable risk factor for cardiovascular disease death, affecting over 1.3 billion people around the globe and is responsible for around half of all strokes and heart attacks. Lowering blood pressure can cut the number of strokes by 35%–40%, heart attacks by 20%–25%, and heart failure by 50%. Yet, despite the ready availability of inexpensive drug treatments, many people remain undiagnosed or inadequately treated.
So, the researchers wanted to find out how well blood pressure is controlled among 40–69 year olds diagnosed with the condition and taking medication to treat it in the UK, as well as pinpointing any relevant factors linked to better or worse control.
The researchers drew on baseline survey data from the UK Biobank (UKB), a large-scale biomedical database and research resource which follows the health of half a million participants. The cohort was aged between 40–69 years at recruitment and lived within 40 km of 22 assessment centres across England, Scotland and Wales between 2006 and 2010.
They took account of potentially influential factors: social and demographic characteristics; cardiovascular disease risk factors (alcohol intake, smoking, physical activity levels, and weight), and blood pressure control (number and type of coexisting cardiometabolic, respiratory, psychiatric and neurological conditions, and number of drugs taken to treat the condition), and a proxy for healthcare use - previous bowel cancer screening.
Among all 459,484 UK Biobank participants, over half 56% (256,203) had high blood pressure. Nearly half (47%, 120,211) were unaware of their condition; and 27% (36,524) of those who were aware were not taking any drugs to treat it.
The final analysis included 99,468 people. Their average age was 62; 46% (45,607) were women. Most (93%; 92,385) were white and around a quarter (25,606) had only been educated to primary school level. Around one in five (19%; 19,344) had been diagnosed with cardiovascular disease; four in 10 (39, 887) were obese; and around one in 10 (9%; 9254) were current smokers. On average, they had been diagnosed with high blood pressure seven years earlier. Just under 14% were on three or more drugs to treat the condition.
Among the 19,344 with cardiovascular disease, around one in five (19%; 3740) were on three or more high blood pressure drugs; as were 9886 (12.5%) of the 79,022 without cardiovascular disease who were neither smokers nor obese.
High blood pressure was controlled in only two out of five treated middle-aged people. Blood pressure was controlled in only around 38% of those on treatment, meaning that nearly two thirds (61,543; 62%) were not being treated properly.
When a higher cut-off blood pressure threshold of less than 160/100 mm Hg was applied, it emerged that 20,573 (21%) weren’t being treated properly for the condition. Nearly 4% (3754) of those who were on treatment had a systolic blood pressure of at least 180 mm Hg or a diastolic blood pressure of at least 110 mm Hg.
Factors associated with poor blood pressure control included older age (60+), male gender, drinking 30 or more units of alcohol a week, black ethnicity and obesity. Low household income (£18,000 a year), low educational attainment, and manual labour jobs were also associated with poor blood pressure control.
‘Having coexisting conditions such as known cardiovascular disease or diabetes was associated with higher probability of control. This may be due to more frequent interaction with the healthcare system and/or appropriate management of those at greater cardiovascular risk,’ says Dr Tapela.
While data presented in this study are from 2006-2010, findings remain relevant to the present day given remaining gaps in hypertension control in the UK and poorer control rates among those with certain co-morbidities, Black people and other groups.
‘More research is needed to understand barriers to high blood pressure control, and the mechanisms underlying the association between it and comorbidities not linked with increased cardiovascular disease risk,’ Dr Tapela adds.