A study to determine whether myalgia is due to statin use

National Heart Foundation guidelines recommend long-term statin therapy in several major patient groups, but adherence rates are low, even following life-threatening events such as acute coronary syndrome. Muscle-related symptoms are the most commonly reported reason for statin discontinuation and about 1 in 5 patients taking statins report some degree of muscular pain. Placebo-controlled trials indicate overall in a treated population most symptoms are not due to the statin, but for an individual patient it is typically impossible to be certain. N-of-1 (single-patient multiple crossover) trials offer a simple, intuitive way to resolve this uncertainty. While N-of-1 trials have been used for more than 20 years, to date, few clinical services in Australia are conducting N-of-1 trials on a regular basis to improve the management of individual patient. Fewer studies have looked at the potential of using N-of-1 trials to determine statin tolerability. A recently published study suggested that N-of-1 trials can improve the assessment of statin-related myalgia in selected patients from endocrinology clinics in Canada. However, the results were limited by its small sample size and the potential for expanded use of N-of-1 trials to improve the compliance of statin therapy among statin intolerant patients remains unclear. The study will include up to 15 N-of-1 trial participants. Patients with prior history of intolerance of both atorvastatin 10 mg AND rosuvastatin 5 mg monotherapy, had statin-related myalgia occurring within three weeks of starting statin therapy and consequently discontinued statin use will be invited to participate. Each person will go through 3 double-blind, crossover comparisons of statin versus matching placebo. Each treatment and control period will last for 3-weeks and there will be a 3-week placebo wash out period after each of the active statin treatment. The total trial period for each participant will be 27 weeks. Myalgia scores will be recorded on a weekly basis during the study period. Brief Pain Inventory Questionnaire will be completed and blood sample collection will be done at baseline and at the end of each active treatment and control period to measure serum CK, ALT, AST, FGF21 and creatinine levels. To avoid unblinding of treatment allocation during the trial period, additional blood samples will be stored to measure lipids’ levels upon study completion. Genotype analysis will also be done at the end of the study to determine if genotype is associated with statin-induced myalgia.