Prevention of cardiovascular diseases

Cardiovascular disease (CVD) remains the leading cause of global morbidity and mortality
1]. The risk factors of abnormal lipids, smoking, hypertension, diabetes, abdominal
obesity, poor diet and irregular physical exercise account for more than 90 % of the
CVD risk in epidemiological studies 2].

The commonest risk factor is hypertension, with a global prevalence estimated at 26.4 %
(972 million adults) in 2000 and a predicted rise of 60 % to a total of 1.56 billion
adults (29.2 %) by 2025 3]. A major predictor for coronary heart disease (CHD) and stroke 4], 5], international guidelines highlight the management of hypertension 6], 7] based on huge clinical outcome trial datasets 8], which show that a net blood pressure (BP) reduction of 10–12 mmHg systolic BP and
5–6 mmHg diastolic BP reduces stroke incidence by 38 % and CHD by 16 % 9]. In absolute terms, treating 1000 patients in four 5-year CVD risk groups observed
in the placebo arms of trials (5-year risks of 11 %, 11–15 %, 15–21 % and 21 %)
with BP-lowering treatment for 5 years would prevent 14 (95 % CI: 8–21), 20 (95 %
CI: 8–31), 24 (95 % CI: 8–40) and 38 (95 % CI: 16–61) cardiovascular events, respectively
(P?=?0.04 for trend) 9].

Interventions that lower low-density lipoprotein cholesterol (LDL-C) concentrations
are also proven to significantly reduce the incidence of CHD and other major vascular
events in a wide range of individuals. A meta-analysis of 14 statin trials showed
that for every 40 mg/dL (1 mmol/L) decrease in LDL-C, it led to a 21 % decrease in
CHD risk after 1 year of treatment 10]. These data were incorporated into clinical guidance, such as the American College
of Cardiology/American Heart Association (ACC/AHA) 11] and National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) III
guidelines 12] in the US; the Joint Task Force of the European Society of Cardiology and Other Societies
on Cardiovascular Disease Prevention in Clinical Practice guidelines in Europe 13]; and the National Institute for Health and Care Excellence (NICE) in the UK, which
all recognise the importance of dyslipidaemia, as well as hypertension and smoking,
as the main risk factors for CVD. They also provide practical tools (Framingham, Systematic
Coronary Risk Evaluation (SCORE) and QRISK 10-year CVD risk algorithms, respectively)
to assist short-term risk estimation in individuals without prior CVD, although there
remain many barriers to guideline implementation in routine clinical practice 14].

However, despite this huge evidence base on the aetiology of CVDs and their treatment
options, many questions still remain unanswered. Some of these are considered in this
special article collection in BMC Medicine, including critical reviews on diagnosing hypertension 15], the potential of PCSK9 antibodies 16], an entirely new class of LDL-C modifiers developed from basic concept to phase III
trials in less than a decade, and the evidence for smoking reduction interventions
17].

In the near future, there will also be an upcoming forum debate on the relative impact
of statins on vascular disease — over 20 years after their introduction and now one
of the most prescribed drugs in the world, there remains much debate on these agents.
The article collection will also present the updated guidance on stroke prevention
in atrial fibrillation (SPAF) which, alongside detection and management of hypertension,
is the most important strategy to prevent stroke. Atrial fibrillation (AF) is the
commonest cardiac arrhythmia, with about 1–2 % of the general population estimated
to be affected 18]. It is a particularly common disorder in older people, with over 5 % over the age
of 65 years suffering from AF and around 10 % of people over the age of 75 years 19], 20], with the prevalence predicted to rise 21], 22]. Patients with AF are at an almost five-fold higher risk of stroke compared to age-matched
individuals with normal sinus rhythm 23], as well as at a twice as high risk of all-cause mortality and heart failure. About
20 % of all ischaemic strokes are attributable to embolism as a result of AF 24]. Not only do patients with AF have more strokes, they also develop more recurrent
strokes, more severe strokes, regardless of age 25], and are more likely to be left with long-term disability and require long-term care
26]. It is a very important topic for patients and for healthcare system payers.

Accompanied by peer-reviewed research papers 27]–30], this article collection, Prevention of cardiovascular diseases, should be of interest to all BMC Medicine readers.