Randomized Trial Comparing N of 1 Trials to Standard Practice to Improve Adherence to Statins in Patients With Diabetes

Randomized Trial Comparing N of 1 Trials to Standard Practice to Improve Adherence to Statins in Patients With Diabetes

Patients who are intolerant of statins in routine practice, but who lack objective evidence of significant harm, will be randomized to receive statins by either n of 1 trials or standard practice. Our hypothesis is that n of 1 trials will improve statin adherence, thereby improving low density lipoprotein cholesterol (LDL-C) levels.

Cholesterol lowering medications called "statins" decrease heart disease in people with diabetes but research shows that many patients are not taking these medications, sometimes because of side effects. In our experience, the side effects attributed to statin therapy are often subjective, non-specific, and not associated with objective evidence for a clinically important problem. The most common example is muscle cramps despite a normal CK level, but other symptoms include fatigue, GI intolerance, and neurological symptoms.

Traditionally, the effects of treatments are determined using randomized controlled trials. N of 1 trials minimize these biases through randomization, double-blinding, and multiple crossovers, and are therefore excellent tools to evaluate adverse effects of therapies when symptoms are non-specific and objective evidence for a causal relationship is ambiguous.

Patients who are intolerant of statins in routine practice, but who lack objective evidence of significant harm, will be randomized to receive statins by either n of 1 trials or standard practice. Our hypothesis is that n of 1 trials will improve statin adherence, thereby improving low density lipoprotein cholesterol (LDL-C) levels. Patients in the n of 1 trials group will be given 1 month courses of either simvastatin or placebo. Patients in the group who are receiving statins according to standard practice will be given a prescription by the doctor in the usual way.

At the end of the study, we will determine if more patients participating in n of 1 trials group are taking statins compared to the patients in the conventional group and if this leads to lower cholesterol levels. We plan to use the results of this small feasibility study to test the methods and to plan a larger study on the same question.

Inclusion Criteria:

• Established diagnosis of type 1 or 2 diabetes
• Age 18-80 years
• Indication for a statin by the 2003 Canadian Diabetes Association (CDA) Clinical Practice Guidelines
• Willingness to re-try a statin despite previous apparent intolerance
• Provision of signed informed consent

Exclusion Criteria:

• Contraindication to a statin: previous rhabdomyolysis, active liver disease or unexplained persistent elevations of serum transaminases (CK, AST, ALT >three times upper limit of normal), pregnancy or lactation
• Impaired renal function: severe renal insufficiency (creatinine clearance <30 ml/min)
• Presence of a condition such as malignancy for which the one-year prognosis is poor
• Inability of the patient to comply with the rigorous conditions of the trial
• Any other condition deemed to render the study harmful to the participant