NEW research validates doctors’ prescribing habits for lipid-lowering drugs in the face of media claims the medications are widely overused.
A large study of dispensing data from the Pharmaceutical Benefits Scheme, published in the MJA, has found that among patients who had coronary heart disease (CHD), diabetes and hypertension, only 8% did not receive lipid-lowering drugs. (1)
By contrast, “only 7% of those not identified as being at high coronary risk were receiving lipid-lowering drugs”, the researchers found.
They wrote that “at limited face value, this is an encouraging statistic, given the high use of statin drugs in Australia”.
The study did not have access to clinical data, instead using dispensing data on co-prescriptions as proxy measures of risk factors. It also only included concession card holders, who make up 65% of all patients who receive statins in Australia.
Of more than 850 000 patients identified in the random sample, about 280 000 were deemed to be at high coronary risk, based on their having three prescriptions within 6 months for drugs used to treat CHD, diabetes or hypertension. The researchers found that 42% had not received any lipid-lowering drugs during the study period.
They found those in middle age (51‒70 years) were most likely to receive lipid-lowering therapy, raising concerns about “a form of age discrimination” among older and younger patients.
This was based on the finding that even among patients with all three of CHD, diabetes and hypertension, lipid-lowering therapy was not prescribed to 21% of those in their 80s and 10% of those under 41, compared with just 4% in their 50s and 60s.
Associate Professor Leon Simons, of the Lipid Research Department at the University of NSW and lead author of the MJA study, told MJA InSight he believed doctors were reluctant to prescribe statins in the elderly of because they were worried about polypharmacy and futility.
By contrast, he said the barrier to use in young patients was likely to be due to their resisting long-term medications in the belief that they were “bulletproof”.
Overall, Professor Simons said the study findings were “very gratifying”.
“We can show high-risk patients are in the main getting the treatment they need”, he said.
Professor Mark Nelson, chair of the Discipline of General Practice at the University of Tasmania and senior research fellow at the Menzies Research Institute, agreed the study suggested doctors were appropriately prescribing statins in high-risk patients.
However, he raised concerns about the study’s reliance on individual risk factors rather than a patient’s absolute risk, arguing that using absolute risk calculators meant the lower prescribing rates among younger patients would be expected.
“Very few people under 40 would have a high absolute risk of cardiovascular disease”, he told MJA InSight.
He also said there were valid concerns about the “safety and futility” of statins in elderly people.
Highlighting the dangers of making assumptions based on dispensing data, Professor Nelson said many young women on metformin would be taking the drug for polycystic ovary disease rather than diabetes.
Dr Robert Grenfell, national director of the Heart Foundation, also warned that some of the patients classified as “high risk” in the study may not in fact be high risk according to an absolute cardiovascular risk assessment.
“This study presents dispensing data only and proxy measures of diagnosis so we can only rely on this as one piece of the puzzle”, he said.
The study comes as the fallout continues over several high-profile controversial articles in the medical literature and lay press suggesting statins are being overused in low-risk patients and have a high rate of potentially dangerous side-effects.
The BMJ this month announced it would not be retracting two articles at the centre of the controversy, which in October last year claimed that 18%–20% of patients taking statins experienced adverse effects. (2)
The articles have since been corrected to say that 9% was a more likely approximation.
BMJ Editor Fiona Godlee wrote on the journal’s website this month that its decision not to retract the article was based on the advice of a panel of seven internationally respected clinicians and researchers who met seven times over 2 months. (3)
Professor Simons told MJA InSight the “damage had already been done” by the BMJ’s decision to publish the initial articles, as surveys and anecdotal GP reports suggested a surge of patients had dumped their statins in the wake of previous publicity questioning the use of statins. (4)
He said while it was true that giving statins to low-risk patients didn’t reduce all-cause mortality, it did result in reduced morbidity.
(Photo: Sheila Terry / Science Photo Library)