Routine liver function testing 'not useful' for simvastatin
By Nigel Praities
Routine monitoring of liver function tests in patients taking simvastatin 40 mg is ‘not useful' as there is almost no risk of hepatitis, concludes a UK study.
The analysis of five years of data from the Heart Protection Study failed to find any significant increase in hepatitis in patients taking the drug compared with placebo.
Among over 20,500 patients with a history of cardiovascular disease or diabetes, there were only six cases of clinical hepatitis in the simvastatin group, versus nine in the placebo group.
The patients were aged 40 to 80 years and those with evidence of liver disease or abnormal liver function were excluded from the study.
The researchers concluded routine liver function testing during treatment with simvastatin at daily doses up to 40mg was ‘not useful, at least in those with normal liver function prior to treatment'.
Study leader Dr Louise Bowman, clinical research fellow at the University of Oxford's Clinical Trial Service Unit, said: ‘Simvastatin is very safe indeed. We didn't find any suggestion of liver abnormalities. But this cannot be extrapolated to any higher dose of simvastatin or any other statins.'
NICE recommends liver function is tested before and within one to three months of starting treatment and again at 12 months.
Dr Kathryn Griffith, a GP in York and chair-elect of the Primary Care Cardiovascular Society, said many GPs carried out liver checks annually, but the new study suggested that this was not needed.
‘I would always recommend that GPs do one test before starting, one as part of follow-up and for the higher doses of simvastatin.
‘But this would save on having annual liver function tests unless you are changing the dose or something else changes in the patient,' she said.
The data also found showed no evidence of any differences in muscle symptoms between groups, with the incidence of myopathy recorded less than 0.1% in patients at high risk of cardiovascular events taking simvastatin.
A spokesperson for the BNF said: ‘We will certainly consider this article and continue to review all the available evidence on the subject, updating our advice for a future edition where necessary.'
A spokesperson from NICE said the new study – published online by BMC Clinical Pharmacology - was ‘theoretically' relevant to its guidance, but refused to say whether it would be taken into account.Advice on liver function testing with statins
‘There is little information available on a rational approach to liver-function monitoring; however, NICE guidelines say liver enzymes should be measured before treatment, and repeated within 3 months and at 12 months of starting treatment, unless indicated at other times by signs or symptoms suggestive of hepatotoxicity.'
‘Routine monitoring of liver function tests during treatment with simvastatin 40 mg is not useful'
HPS collaborative group. BMC Clinical Pharmacology 2009; 9: 6