Tue, 2021-11-30 18:55 by Dr. Colin Alert
Why we should we go on the offence against blood pressures?
Dr. C. V. Alert, MB BS, DM. FCCFP
Family Physician.
There is no doubt that “Covid Covid Covid” has completely hijacked the attention and resources away from almost all other health issues, around the world. In the ‘good old pre-covid days’, our main medical challenge, at least in the number of persons affected, came from the chronic non-communicable diseases (CNCDs or NCDs}. As soon as covid vaccines became available, our health officials were quick to prioritize patients with NCDs to receive the vaccines, fearing that should these individuals contract covid the suffering and deaths could be enormous. A combination of factors, including limited supplies of the vaccine initially and the emergency of significant vaccine hesitancy, fueled by the social media, meant that many patients with these ncds, also called co-morbidities, did not receive the vaccine. These factors, along with the emergence of mutant strains of the covid-19 virus, collaborated to see a sharp rise in deaths in patients with these co-morbidities.
Pre Covid-19 hypertension mortality rates, age standardized, per 100000 persons.
World Health rankings: https// www.worldlifeexpectancy.com/world-health-rankings
Even before covid-19, Caribbean countries had very high mortality rates from diabetes and hypertension, many times higher than our ‘big brother’ countries to the north of us, and even our cousin Cuba whose shores are also washed by the Caribbean sea.
The emergence of improved management protocols for diabetes mellitus, in terms of newer smart drug classes and improved monitoring devices that allow continuous glucose monitoring (CGM) are expensive options for our national health budgets. There are ‘cheaper’ options, backed up by research studies, that we can embrace to reduce the suffering and death associated with hypertension. It is time that we looked again at hypertension.
Lower BP target.
Among patients at high risk for cardiovascular events but without diabetes, targeting a systolic blood pressure of less than 120 mm Hg, as compared with less than 140 mm Hg, resulted in lower rates of fatal and nonfatal major cardiovascular events and death from any cause, although significantly higher rates of some adverse events were observed in the intensive-treatment group. These were the main findings of the SPRINT Study (1).
Findings from the intensive treatment group in SPRINT have changed the traditional target for lowering blood pressure from less than 140/90 mm Hg to less than 130/80 mm Hg (2).
Salt Reduction.
It has long been the concern of physicians that, in countries of the Caribbean with a high prevalence of hypertension, far too many people are consuming too much salt. The Barbados Salt Study (3), a sub-study of the Health of the Nation Study, found that 79% of women and 89% of men in Barbados consume more than 1.5g/day of sodium, the recommended daily allowance.
Switching from regular salt to a low-sodium salt substitute has major public health benefits, including a reduction in stroke, cardiovascular events, and death, a new landmark study shows (4).
The Salt Substitute and Stroke Study (SSaSS) was conducted in almost 21,000 people with a history of stroke or high blood pressure in rural China, with half of them using a lower-sodium salt substitute instead of regular salt.
Results (4) showed that after 5 years, those using the salt substitute had a 14% reduction in strokes, a 13% reduction in major cardiovascular events, and a 12% reduction in death. These benefits were achieved without any apparent adverse effects.
So we have a roadmap for reducing hypertension and some of its major cardiovascular complications in high risk individuals.
Anti-hypertensive Drugs and Diabetes.
Blood pressure lowering can be an effective strategy for the prevention of new-onset type 2 diabetes, according to a recent meta-analysis published in the Lancet.(5) Established pharmacological interventions, however, have qualitatively and quantatively different effects on diabetes. Researchers investigated the effects of five major types of blood pressure drugs from 22 clinical trials compared with a placebo. They found angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) had the strongest protective effect, both reducing someone’s relative risk of developing diabetes by 16%. Recent anti-hypertensive treatment guidelines have promoted single pill combinations (SPCs) containing an ACE or an ARB as the first line drug therapies for hypertension.
Other types of blood pressure-lowering drugs were not protective. Calcium channel blockers had no effect on type 2 diabetes risk, while beta blockers and thiazide diuretics actually increased the risk despite their known beneficial effects in preventing heart attacks and strokes (5).
Blood Pressure Lowering and Cardiovascular Disease.
Blood pressure (BP)–lowering treatment is associated with lower risk for cardiovascular events (CVEs) across a wide range of BP levels and in patients with and without CV disease, according to a meta-analysis (5).
Researchers examined individual-patient data on some 345,000 adults who were randomized to different BP-lowering or control regimens across nearly 50 trials. Patients’ baseline BP levels varied widely and those with/without CV disease were included.
During a median 4 years’ follow-up, 12% of participants experienced at least one major CV event. Among those with CV disease at baseline, a 5-mm-Hg reduction in BP was associated with an 11% reduction in risk for CV events. For those without prevalent CV disease, the risk reduction was 9%. Significant benefits were seen regardless of baseline BP, even at levels below 120 mm Hg.
This analysis suggest that physicians should consider anti-hypertensive drugs as a tool for reducing cardiovascular risk, in patients with hypertension and/or other high risk cardiovascular risk factors.
Blood pressure lowering and cognitive impairment.
In the Caribbean many elderly patients with ‘failing memory’ are often labeled as dementia. Because a formal diagnosis of Alzheimers dementia is an expensive option, many patients are tagged as having Alzheimers Dementia on clinical grounds only, without formal investigational confirmation. But the high prevalence of uncontrolled ncds in our populations suggest that we should have a lot of vascular dementia, as opposed to Alzheimers dementia.
The SPRINT Memory and Cognition IN Decreased Hypertension (SPRINT MIND) study (7) tested whether aiming at the lower systolic BP target reduced the risk of developing the incidence of probable dementia, mild cognitive impairment (MCI), and a composite outcome of MCI or probable dementia.
SPRINT MIND demonstrated that intensive BP control did not result in harm and may be beneficial to the brain or cognition after a median intervention period of 3.34 years and an overall median follow-up of 5.11 years. SPRINT MIND is the first trial to identify an intervention that significantly reduces the occurrence of MCI as well as the combined occurrence of MCI or dementia.
Conclusion.
In all likelihood, both covid and the NCDs are here to stay. Blood pressure reduction, by adopting appropriate diet and exercise regimes, and by aggressive treatment of blood pressure in patients with or without high cardiovascular risk, offers the opportunity to lower the suffering and death associated with elevated blood pressures. In turn, this may free up vital finances needed to tackle other health issues, including covid.
It is unfortunate that studies show that significant numbers of patients treated for uncontrolled hypertension do not achieve blood pressure targets, increasing the chances of the patients suffering significant morbidity and mortality from hypertension. Apart from introducing measures to prevent hypertension in the first place – Primary Prevention – It is time that our health leaders put in place protocols that promote better management of our patients with hypertension. We need screening protocols, and awareness of hypertension needs to be actively promoted. The Health of the Nation Study showed that, in Barbados, 42% of the hypertensive patients on treatment did not have their blood pressures below 140/90 mmhg: are doctor visits and anti-hypertensive medications being wasted?
Unfortunately, many patients, and some physicians, do not appreciate the concept of ‘high cardiovascular risk’ in our countries. How much does ‘family history of cardiovascular disease, especially if death from a cardiovascular cause is premature’, play in our clinical decision making? While many think of overweight and especially obesity as primarily cosmetic concerns, the medical evidence supports the position that obesity is an independent risk factor for cardiovascular disease, as well as a predisposing factor for diabetes, hypertension and dyslipidemias, the other three major cardiovascular risk factors. Nonetheless, our public health officials have failed to show the interest, enthusiasm and resources in treating obesity that they have shown towards the other major cardiovascular risk factors.
Caribbean countries, and Caribbean economies, can certainly benefit from improved blood pressure management and lower blood pressure targets, both in patients diagnosed with hypertension, and non-hypertensive patients with high cardiovascular risk.
References:
- The SPRINT Research Group. A Randomized Trial of Intensive versus Standard Blood-Pressure Control. N Engl J Med 2015: 373: 2103-2116.
- Whelton PK et al : 2017 Guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on clinical practice guidelines Hypertension. 2018; 71: 1269-1324
- Harris R, et al . The Barbados National Salt Study. Findings from a sub-study of the Health of the Nation Survey. The Barbados Health of the Nation Survey: Core Findings. Chronic Disease Research Centre, The University of the West Indies and the Barbados Ministry of Health: St Michael, Barbados
- Neal B, Wu Y, et al . Effect of salt substitution on cardiovascular events and death. N Engl J Med. 2021;385(12):1067-1077.
- Nazarzadeh M, et al: Blood pressure lowering and the risk of new-onset diabetes: an individual participant date meta-analysis. Lancet No. 398 # 10313, p 1777
- Blood Pressure Lowering Treatment Trialists’ Collaboration: Pharmacological blood pressure lowering for primary and secondary prevention of cardiovascular disease across different levels of blood pressure: an individual participant-level data meta-analysis. Lancet 397, Issue 10285, p1625-1636, May 01, 2021
- Williamson JD, Pajewski NM, Auchus AP, et al. Effect of intensive vs. standard blood pressure control on probable dementia. A randomized clinical trial. JAMA. 2019;321:553–561.