Stroke is a significant public health issue, which can be chiefly divided into ischaemic and haemorrhagic subtypes. In the UK, more than 200,000 people experience stroke every year10, which thus makes it a significant public health issue. Cardio-embolism and heart diseases are closely related to stroke therefore throughout this essay prevention strategies regarding cardiac conditions are also included for contemplation. There are two major types of prevention strategies as employed to reduce the risk of stroke: high-risk and population-targeted prevention strategies. Their pros and cons are elaborated accordingly as follows.
Comparison between the two types of prevention strategies requires our attention to the tendency of occurrence of cardiovascular events, mortality and quality-adjusted life-years.2 A more aggressive pharmacological intervention is utilised for high-risk strategies, involving statins, beta-blockers, angiotensin-converting enzyme inhibitors (ACEIs) and aspirin1 since they concern multiple risk factors. For population-wide prevention strategies1, they adopt a slightly dissimilar approach, emphasising on management of blood pressure or blood cholesterol in terms of pharmacological intervention, whilst simultaneously reducing certain behavioural risk factors, inclusive of tobacco cessation, unhealthy diet, physical inactivity, being overweight and harmful use of alcohol4. A New Zealand study4 has proposed that as stroke is divided into two categories, different approaches should be employed for alleviating the issue. For developed countries, there exists higher propensity of ischaemic stroke, thus the reduction of behavioural risks encompassing aspects such as diet, physical training and obesity is deemed more feasible. Treatment of conditions associated with atherosclerosis, particularly highlighting hypertension, should also be taken into account. For developing countries, haemorrhagic stroke should instead be targeted, with early detection, management of elevated blood pressure and reduced exposure to polluted air being the key characteristics of an effective treatment plan.
For high-risk strategies, patients with 10-year Framingham event risk of >30% experience a drop in risk of 11%1, provided that the aforementioned aggressive pharmacological treatment is in place. Since the drugs are utilised in combat of different conditions, in which aspirin reduces the risk of bleeding and beta-blockers, overwhelming burden of the heart, this can reap more benefits in the long-term when confronting patients with more risk factors and higher inductive potential of heart conditions.
However, despite the edge of tackling a variety of conditions concomitantly, only a small sample of the population is benefitted. Emberson J et al1 further suggests variations in thresholds which can hamper the reproduction of predicted results. For instance, treating patients with ³ 20% Framingham risk score reaps 34% of risk reduction. Likewise, for those bearing ³ 15% Framingham risk score, the extent of reduction is increased to 49%. However, the same study has reinstated the futility of decreasing the threshold to a low level, such as 5% as proposed by Third Joint Task Force11, financial and pharmacological risk implications such as associated interventional side effects, should not be overlooked. Such side effects can be varied, where ACEIs might induce dry cough owing to bradykinin accumulation.
The inability to identify patients with high risk of cardiovascular disease, mostly owing to incomplete risk assessment and insufficiency in the access of healthcare, also stars as a major disadvantage of high-risk strategies2. Cost-effectiveness is essentially lower than population-wide strategies, as laboratory tests and doctor visits are necessary for risk stratification4. As cardiovascular diseases encompass fluctuations over a period of time, constant monitoring is deemed necessary in turn demanding greater attention of community services. Moreover, even after risk stratification, low to medium-risk patients might be tempted not to take primary precautions towards cardiovascular diseases and stroke6.
Shifting our focus to the population-wide approach, behavioural factors are targeted and Emberson J et al1 contrasts so with high-risk strategies in terms of efficacy, a long-term reduction of serum total cholesterol and systolic blood pressure for 5% can yield a 26% decrease of first occurrences of cardiovascular events. If 10% reduction is contrived, the extent of the decrease can be brought to 45%. The major advantage2 is benefitting a larger population where reducing risk factors mildly can contribute to major risk reductions of disease occurrence already. However, even if side effects are slightly more severe, the desirability of the strategy decreases12, as evidenced by aspirin administration as a modality for thrombotic prophylaxis.
Despite there being better coverage of the population, population-wide strategies can fail to take into account the severity of regression dilution bias1, which is the underestimation of the importance of risk factors presented after the employment of baseline measures. A study4 mentioned that the broad approach of such strategies might not be proven practical enough to merit implementation since for cardiovascular diseases and stroke, since the availability of health-related industries cannot correspond with the required demand, such as the advertisement of healthier lifestyles and alterations in legislation exemplified by sugar taxation. Geographical variations might also influence the efficacy of such an approach. For a study concentrating on developing countries6, reference to climatic conditions and the region’s practical needs is indispensable. Salt intake, although promoted to be reduced in developed countries to combat hypertension, a key factor to stroke and heart diseases, might be otherwise deemed necessary in African countries due to meteorological variations.
It is therefore advised to utilise both strategies to combat stroke and heart disease effectively.
REFERENCES:
1. Emberson, J. (2019). Evaluating the impact of population and high-risk strategies for the primary prevention of cardiovascular disease. [online] Oxford Academic. Available at: https://academic.oup.com/eurheartj/article/25/6/484/494953 [Accessed 18 Jan. 2019].
2. M Zulman, D. (2019). The Relative Merits of Population-Based and Targeted Prevention Strategies. [online] NCBI. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2690369/ [Accessed 18 Jan. 2019].
3. Rundek, T. and Sacco, R. (2019). Risk Factor Management to Prevent First Stroke. [online] NCBI. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2666965/ [Accessed 18 Jan. 2019].
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10. Stroke.org.uk. (2019). State of the Nation, Stroke Statistics (Feb 2018). [online] Available at: https://www.stroke.org.uk/system/files/sotn_2018.pdf [Accessed 18 Jan. 2019].
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12. Gage BF, Cardinalli AB, Albers GW, Owens DK. Cost-effectiveness of Warfarin and Aspirin for Prophylaxis of Stroke in Patients With Nonvalvular Atrial Fibrillation. JAMA. 1995;274(23):1839–1845. doi:10.1001/jama.1995.03530230025025.
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