Guidelines on managing dyslipaemia for cardiovascular risk reduction; a missed opportunity

The publication of the clinical practice guide on the management of hypercholesterolemia in November this year (1), by the American College of Cardiology (ACC) and the American Heart Association (AHA), has attracted multiple reviews in leading scientific journals. The latest guidelines available in the management of dyslipaemia were from 2004 by the ATP III (Third Adult Treatment Panel), in which clinical decisions are made on the basis of cholesterol levels and establishing cardiovascular risk, based on LDL cholesterol levels.

Atherosclerotic cardiovascular disease (CVD) is the main cause of mortality in the elderly, as well as of disability, however the main tools for calculating CVD risk delimit age (Framingham, REGICOR up to 74 years and SCORE up to 65 years) as they are close to life expectancy.

The indications for treatment with statins would be currently;

- Presence of established atherosclerotic cardiovascular disease, if under 75 years of high intensity (Atorvastatin 40-80 mg, Rosuvastatin 20-40 mg) and if over 75 years of moderate intensity (Simvastatin 20-40 mg, Pravastatin 40-80 mg).

- Presence of LDLc ≥ 190 mg/dl should receive high intensity treatment.

- Diabetic patients aged 40-75 years with LDLc between 70- 189 mg/dl, without established atherosclerotic disease, should receive moderate intensity treatment, and if the RCV is ≥ 7.5% high intensity.

- Patients without cardiovascular disease, nor diabetes, with LDLc between 70-189 mg/dl, who have an estimated cardiovascular risk (CRV) at 10 years ≥ 7.5% should receive moderate or intensive statin treatment.

The 10 year CCR is estimated by means of a proprietary calculation (Pooled Cohort Risk Assessment Equations), which takes into account age, sex, race, cholesterol, HDLc, diabetes, smoking and blood pressure, in the 40-79 year range. In patients over 70 years of age, in the case of men with no other cardiovascular risk factors, a CCR of 27% is obtained and in women of 13.6%, with a cut-off point for intervention of 7.5%.

These American recommendations contrast with European cardiovascular mortality rates, such as those in Spain, which are 25-50% lower, with similar risk factor prevalence rates.

If we evaluate the number needed to treat NNT (2.3) of 5 year statin treatment in patients with established CV disease it is 83 for mortality, reducing the presence of ischemic heart disease by 2.6% and stroke by 0.8%; in primary prevention (4) the NNT is 60 for a non-fatal cardiac ischemic event, reducing ischemic heart disease by 1.6% and stroke by 0.4%. The risk of developing myopathy is 10% and the presence of diabetes 2% at 5 years.

In the period 1996-2011 $120 billion has been spent on statins. With these data it is estimated that a billion people need to be treated worldwide, with the increase in costs that this entails, also taking into account that more than 50% of the panel of experts present possible conflicts of interest with the pharmaceutical industry (8 out of 15, no such data were available in 2004).

Although it has been demonstrated the relationship between hypercholesterolemia and the presence of VC disease, being logarithmic this association, and that levels below 70 mg/dl of LDL c persist in a beneficial balance from the VC point of view, however there is a large amount of documentation in which a control of certain subrogated variables is not associated with an improvement in the primary objectives. This uncertainty is greater in elderly patients, where there are fewer clinical trials, however the prevalence of CV disease is very relevant, as those aspects concerning the safety of the interventions, being one of the target population groups that consumes more hypolipemic treatments.

One of the strongest points of the guide is the methodology used, with evidence-based medicine criteria, establishing the level of recommendation with an extensive bibliographic review, extending the age range to 79 years; However, no mention is made of aspects such as life expectancy or functional capacity, although there is a specific section for patients over 75 years of age where it is considered that in the event of good tolerance to the treatment it should be maintained and there are doubts about safety aspects in secondary prevention regarding the intensity of the intervention, also mentioning the comorbidities present, treatments, patient and carer preferences.

The paradigm of cholesterol control has been modified, being more relevant the type, size and concentration of LDLc lipoproteins, as well as the assessment of the global CVC, being the effectiveness of the interventions superior in ischemic cardiopathy than in stroke. In patients over 80 years old, decision making should be carried out according to the patient's global objectives, establishing adequately the role of each medicine in the therapeutic plan and the time needed to achieve them.

"There is no art more difficult to acquire than the art of observation". (W. Osler)

1. http://circ.ahajournals.org/content/early/2013/11/11/01.cir.0000437738.63853.7a

2. Ridker et al. Rosuvastatin to prevent vascular events in men and women with elevated c-reactive protein. NEJM. 2008; 359(21): 2195-2207.

3. CTT Collaborators. Efficacy and safety of cholesterol-lowering treatment: prospective meta-analysis of data from 90 056 participants in 14 randomised trials of statins. Lancet. 2005; 366: 1267-1278.

4. Taylor F, Ward K, Moore TH, Burke M, Davey Smith G, Casas JP, Ebrahim S.
Statins for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2011 Jan 19;(1):CD004816. Review. PubMed PMID: 21249663.