Dr. Judith Finegold of the National Heart and Lung Institute in London said an analysis of placebo-controlled randomized trials of statins found only a small minority of side effects reported were actually attributable to them. Almost all the side effects reported in these trials "occurred when patients were administered placebo," investigators said.
"Patients and doctors need clear reliable information about benefits and risks to make informed decisions," the study authors wrote.
The study analyzed the prevalence of side effects in 29 eligible randomized controlled trials performed for the primary 46,262 participants and 37,618 secondary participants. Data on all adverse effects, cardiovascular events and death were recorded in both the treatment and control, placebo, arms of the studies.
Using a statistical model, the investigators calculated the increase in risk for each side effect in each group.
The list of side effects assessed included: nausea, renal disorder, myopathy and muscle breakdown, muscle ache, insomnia, fatigue and gastrointestinal disturbance. Only the risk of new onset diabetes was increased by statin therapy, the study said.
Across both primary and secondary prevention trials, the rate of developing diabetes with statins was 3 percent, against 2.4 percent with placebo, thus indicating around 1-in-5 of new cases of diabetes was actually caused by statins, the researchers said.
However, the many side effects commonly attributed to statins such as muscular weakness, fatigue, muscle aches and muscle break down were no more common in the statin arms of these trials than in the placebo arms, the study said.