Approach to identifying and managing atherogenic dyslipidemia

Stents and statins have become our fallback position when dealing with cardiovascular risk. Damaging lifestyle choices have resulted from the environment of dietary and physical activity defaults brought about by industrialization, flawed economics and advancing technologies. Despite this there is still good evidence that proper diet and exercise habits can be as potent as our drugs and devices.

The INTERHEART study (1) identified poor diet, inactivity, stress and increased waist circumference as additional risk determinants for cardiometabolic disease in addition to, and independent of, the currently used Framingham risk factors. This study suggested that smoking, sedentary lifestyle and low consumption of fruits and vegetables could represent 80% of population attributable risk for cardiovascular disease.

The American Heart Association (AHA) has stated that cardiorespiratory fitness is one of the most important predictors of individual risk for future cardiovascular disease(2). A large prospective cohort study over 10 years showed a benefit for exercise equal to or exceeding that from statins(3). The relative benefit was up to 30% and showed a dose response. The benefits from exercise and statins were additive.

The Mediterranean diet was shown in a randomized controlled trial (RCT) of 7000 patients over 5 years to reduce cardiovascular end points with a hazard ratio of 0.70(4). This diet also reduced the impact of components of the metabolic syndrome in a meta-analysis including over 500,000 patients(5). The effect was particularly potent when physical activity was included. A Cochrane review suggested modest benefit in selected RCT's(6).

Recently published and revised AHA lipid guidelines (7) have finally dispensed with therapeutic targets and thresholds referencing LDL levels. These had never been evidence based. Risk assessment is now to be based on 10-year Framingham risk score, with a threshold for statin treatment in the population suggested to be as low as 7.5%. The guidelines are careful, however, to point out that this threshold decision for the individual patient should be decided jointly by the physician and the patient. This is an opportunity to remind the patient that there are modifiable lifestyle options that might be used in place of, or in addition to, statins.

The argument persists, however, that there is an increasing number of people with low Framingham scores who are at high long-term cardiometabolic risk. These patients are often obese with increased waist circumference, and may have glucose intolerance with low HDL's and high triglycerides. If an effective early commitment to diet and exercise cannot be reached, it may be appropriate to have a low threshold for institution of statin therapy.

There will be many disagreements to come regarding thresholds for statin therapy. We do, after all have effective alternatives involving life choices. This debate is the basis of good science, and will bring further clarity to these issues over time. If the public can appreciate modifiable life choices as cardiac risk factors, we may yet see success similar to that achieved with smoking cessation.

1. Yusuf S, Hawken S, ?unpuu S, Dans T, Avezum A, Lanas F, et al. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): a case-control study. Lancet 2004; 364: 937-952.

2. Kaminsky LA, et al. The Importance of Cardiorespiratory Fitness in the United States: The Need for a National Registry A Policy Statement From the American Heart Association. Circulation 2013; 127(5): 652-662

3. Kokkinos PF, et al. Interactive effects of fitness and statin treatment on mortality risk in veterans with dyslipidaemia: a cohort study. Lancet 2013; 381(9864): 394-399

4. Estruch R, et al. Primary prevention of cardiovascular disease with a mediterranean diet. N Engl J Med 2013; 368(14): 1279-1290.

5. Kastorini CM, et al. The effect of mediterranean diet on metabolic syndrome and its components: a meta-analysis of 50 studies and 534,906 individuals. J Am Coll Cardiol. 2011;57(11):1299-1313.

6. Rees K, et al. 'Mediterranean' dietary pattern for the primary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews 2013, Issue 8. Art. No.: CD009825.

7. Stone NJ, et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2013; Available from: http://circ.ahajournals.org/content/early/2013/11/11/01.cir.0000437738.63853.7a.citation. Accessed Nov.18, 2013

Conflict of Interest:

None declared

This is most certainly a practice changing article that will lower the treatment threshold of dyslipidemia. It will be interesting to see the effect that this will have on the occurance of cardiovascular events over the next ten years. It is important to remember that treatment with statins should never replace management of modifiable risk factors by not smoking, exercising, eating healthy foods with low fat, low sodium and high fiber, and developing effective stress management techniques.

Conflict of Interest:

None declared