An estimated 16 people die from cardiovascular disease (CVD) in Singapore every day, accounting for 29.6% of all deaths in 2015. This essentially equates to one out of three deaths in Singapore being caused by either heart disease or stroke.

In a similar trend in Malaysia, according to the latest WHO data as of May 2014, CVD-linked deaths in Malaysia reached 29,363 or 23.1% of total deaths. Moreover, greater numbers of younger Malaysians are now being diagnosed with heart diseases, and according to professor Wan Azman, the chief editor of four National Cardiovascular Database Annual Reports, a huge contributing factor for these exceptionally high rates in Malaysia is the other risk factors they have. He also noted that the high prevalence of cardiovascular risks gives rise to a notably higher rate of disease progression.

Role of statins in CVD

Despite this, there is a wide variation in statin use across cardiology practices here and all over the world with little adherence to clinical guidelines despite the current recommendations. This is due in part to contradicting evidences which emerge and depending also on the biophysical profile of the patient.

Statins inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, an enzyme which is involved in the synthesis of cholesterol. Low density lipoprotein (LDL) cholesterol which is often labelled as the ‘bad cholesterol’ in layman’s terms is lowered by reducing its production in the liver and increasing its removal from the circulation. By lowering the LDL, this serves to reduce the major risk factor for cardiovascular disease.

How well do statins work?

The Cholesterol Treatment Trialists Collaboration reviewed data from 27 clinical trials of statins which involved over 170,000 participants in total. They looked at both primary and secondary prevention and reported a 20% relative risk reduction per 1 mmol/L reduction in LDL cholesterol concentration for major vascular events.

These benefits were seen in both men and women, at ages ranging from just under 60 years to above 70 years, in people with and without cardiovascular disease, and also in those with high and low CVD risks. Despite all the supporting literature, according to the Journal of the American College of Cardiology nearly two out of five people with diabetes who could benefit from statins to lower their risk of future heart attack, stroke and related death were not prescribed one.

Gaps between evidence based medicine and clinical practice

As a clinician, I would strongly advocate that the global number of statin-indicated persons should be increased, and clinicians should be prompted to rethink conversations about initiating new statin therapy. The benefits of statins in primary prevention of CVD is undeniably less convincing than in secondary prevention, although higher CVD risk is associated with greater statin benefit.

Thus, clinicians must engage patients in a shared decision about starting new statin therapy, which should involve discussion about the risks and benefits of therapy and current health status. Research has identified nonadherence to statin therapy as a factor associated with reduced clinical benefits of statin therapy.

Clinicians should also be aware of patient-specific factors associated with noncompliance and implement strategies to improve adherence as indicated. Data on the impact of adherence improvement strategies and the accuracy of how we currently measure adherence are lacking and this may be the contributing factor to conflicting evidence of the benefits in statin usage.

Additionally, research focusing on patient preferences and reported outcomes would better qualify studies which highlight that adverse effects of statins and the lack of efficacy in the control group of patients.

The use of statins with hypercholesterolaemia and known CVD is well established. Current European Society of Cardiology guidelines recommend immediate initiation of drugs in addition to lifestyle intervention in these patients at high or very high cardiovascular risk. In these cases, statins are generally chosen as the first-choice drug intervention, in consideration of the overwhelming evidence showing a reduction in all-cause mortality and major adverse cardiac events (MACE).

In contrast, primary prevention with statins is not well implemented. However this might be related to a lack of public awareness regarding the actual risk associated with prolonged exposure to high concentrations of LDL cholesterol.

To this point, the American Heart Association and American College of Cardiology guidelines on the treatment of blood cholesterol emphasise that primary prevention using high-dose statins in individuals with LDL cholesterol of above 190 mg/dL induces a benefit in atherosclerotic cardiovascular risk reduction that clearly exceeds the potential for adverse effects.

With guidelines from both the European and American healthcare advocating the use of statins in primary prevention earlier and more frequently, this clearly puts the evidence of its efficacy into perspective with new insights in terms of safety issues. MIMS


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