Living With Statins - Interventional Exercise Study

Background:

Hypercholesterolemia and statin use in Denmark

Simvastatin is the most commonly prescribed statin, a class of drugs that inhibit hydroxyl-methyl-glutaryl (HMG) coenzyme A reductase, and thereby blocking biosynthesis of cholesterol in the liver. Simvastatin is prescribed for individuals with elevated low-density lipoprotein cholesterol (LDL-C) and/or total cholesterol, because these clinical parameters are viewed as a risk factor for cardiovascular-disease (CVD), even in the absence of other health problems or risk factors, such as previous myocardial infarction, diabetes or hypertension.

Approximately 40% of the prescriptions for statins are issued for primary prevention of elevated cholesterol by general practitioners to patients without bodily symptoms or signs. Only the "cholesterol number" makes the risk of heart attack and stroke visible. The lack of symptoms is likely to be of importance for patients' adherence to treatment as is adverse effects. A number of factors, such as information in mass media and changes in daily life, may affect the decision to take the treatment

Treatment guidelines for hypercholesterolemia:

The guidelines indicate preventive treatment with statins is appropriate in individuals with >10% predicted risk of a major vascular event within 5 years, while, some, but not all opinion-leaders advocate a 5% threshold. Nevertheless, statin therapy failed to reduce all-cause mortality in a meta-study of 65,229 patients without CVD, some of whom had diabetes. Similarly, a Cochrane review analysis, which included some studies in which more than 10% of the patients had history of CVD, showed only 0.5% reduction in all-cause mortality, indicating that for every 200 patients taking statins daily for 5 years, 1 death would be prevented. These data suggest that more conservative use of statins to prevent CVD in otherwise healthy individuals at low risk for future CVD may be warranted.

The downside:

Rhabdomyolysis (skeletal muscle cell death) is an infrequent but serious side-effect of statin use, that can on rare occasion lead to acute renal failure and death (i.e., 1.5 deaths per 106 prescriptions). Statin use is much more frequently associated with muscle dysfunction, including myalgia (muscle pain), cramps, and weakness. The reported incidence of myalgia varies from 1% (pharmaceutical company reports) to as high as 75% in statin-treated athletes. Mild to severe myalgia is a strong disincentive to regular exercise, and because regular exercise is one of the critical life-style approaches to preventing CVD and reducing blood cholesterol, this is a significant down-side of statin use. Regular exercise is also effective in preventing and treating obesity and type 2 diabetes, which themselves are risk factors for CVD.

The mechanism behind the myalgia is not known. However, the investigators behind this study has recently demonstrated that muscle mitochondrial function is impaired with statin treatment and the Q10 protein may play a key role in this. In addition, the statins also negatively affect the glucose tolerance, increasing the risk of type 2 diabetes.

Research questions:

The overarching research question is: why does statin treatment cause muscle pain? Does statin treatment impair (or even prohibit) physical exercise training? Furthermore the following questions will be investigated:

A. Does statin treatment cause:

1. Decreased muscle strength?

2. Skeletal muscle inflammation?

3. Decreased mitochondrial respiratory function? B. Abnormal glucose homeostasis?

Re question A & B: If so, can physical training counteract this effect of statin treatment?

Methodology:

Cohort

Patients that fulfil defined inclusion and exclusion criteria will be recruited from General Practice clinics in Copenhagen and news paper advertisements. The vast majority of these patients are being assessed on basis of the HeartScore risk estimation system that offers direct estimation of the ten-year risk of fatal cardiovascular disease in a format suited to the constraints of clinical practice. A staggered recruitment will be implemented.

30 men (age: 40-70 years; BMI: 25-35 kg/m2) before initiation of a statin treatment as primary prevention are recruited. No other risk factors for CVD except elevated total cholesterol (>6 mmol/l) and/or elevated LDL cholesterol (>3,5 mmol/l) and mild hypertension (<160/100 mm Hg) must be present.

The patients will be allocated (randomization by drawing a lot) to one of three groups:

- Physical exercise training and Simvastatin 40 mg/day and Q10 placebo

- Physical exercise training and Simvastatin 40 mg/day and Q10 400 mg/day supplementation

- Physical exercise training, Simvastatin placebo and Q10 placebo

The intervention period is 8 weeks with a series of experimental days before and after.

Experimental days (identical before and after the interventions):

Information day: health examination, ECG and Maximal oxygen uptake take (VO2 max).

Day 1 (overnight fasting, approximately 5 hours):

- Dual energy x-ray absorptiometry (DXA) scan (body composition and body fat).

- Oral glucose tolerance test + score questionnaire for muscle pain/discomfort (incl. Visual Analog Scale)

- Isokinetic strength and Rate of Force Development (PowerRig and KinCom dynamometer).

- Repeated VO2-max-test

Day 2 (overnight fasting approximately 7 hours):

- Muscle biopsy, vastus lateralis

- 2 step Euglycemic, hyperinsulinaemic clamp.

Training programme All training is supervised and takes place at the department. The training is aerobic, bicycle ergometer training (45 min/session at 60-70% of VO2max) three times a week for 8 weeks.