Previous research has shown that sleep deprivation can raise insulin resistance and cause weight gain, potentially increasing diabetes risk.
GPs should consider changing statins and report the event in any patients on simvastatin who show sleep disturbances, said Dr Beatrice Golomb, from the University of California.
'If they're having sleep problems then it might be prudent to think of changing medication to a different statin,' she said.
Sleep deprivation, as with all adverse effects of statins, should be considered by policy makers when making blanket recommendations for statin use, added Dr Golomb.
This casts doubt on the wide-reaching effects of the DoH push for GPs to switch patients to simvastatin to save NHS money. The switch could save up to £2 billion over five years.
For the double-blind trial, 1,000 men and women with moderately high LDL-cholesterol levels of 115-190mg/dl were randomly assigned to 20mg simvastatin, 40mg pravastatin or placebo for six months. Patients had no known cardiovascular disease or diabetes.
Using a visual analogue scale of sleep quality called the Leeds scale, researchers measured perceived sleep quality at baseline.
Any change in sleep quality was assessed at six-month follow-up. While all three groups had comparable sleep quality at baseline, simvastatin was associated with worse sleep quality than placebo or pravastatin, with sleep worsening by an average of 10 per cent. In around 5 per cent of patients the outcomes were severe, leading to a 15 per cent worsening of sleep quality.
Dr Golomb told delegates at the American Heart Association scientific sessions that research was needed to see if sleep deprivation was dose-dependent.
Since simvastatin has become generic there has been a growing trend to use it at high doses to replace lower dose atorvastatin when aggressive therapy is needed.
AHA scientific sessions 4-7 November 2007, Orlando, Florida
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