Polypill will not change prevention of heart disease
http://www.100md.com
《英国医生杂志》
Claims that the "polypill"—a combination of a statin, three antihypertensive drugs, folic acid, and aspirin—will cause a major change in the primary prevention of cardiovascular disease are flawed because they are extrapolated from evidence for the individual components, an epidemiologist claimed last week.
Shah Ebrahim, professor of epidemiology of ageing at the University of Bristol, argued that there was only theoretical evidence for the additive effects of the components of the polypill and that it was unlikely to translate into clinical practice.
Speaking at a debate at the recent European Society of Cardiology's annual meeting in Germany, he also argued that there was a risk of serious adverse effects that would reduce long term compliance and so reduce the benefits. Finally, he calculated that the cost effectiveness of the polypill was poorer than that of other preventive options.
Professor Ebrahim was commenting on claims made in a series of papers published recently in the BMJ, including one that said that the polypill could prevent 88% of ischaemic heart disease events and 80% of strokes ( BMJ 2003;326: 1419-24).
The polypill was designed to reduce four cardiovascular risk factors simultaneously: low density lipoprotein cholesterol concentration, blood pressure, serum homocysteine concentration, and platelet function. Its efficacy was quantified from meta-analyses of the effects of the components. It was argued that a third of people taking this pill from the age of 55 would benefit, gaining an average of about 11 years of life free from an ischaemic heart disease event or stroke.
These claims were unlikely to translate into clinical practice, argued Professor Ebrahim. "There is only weak evidence of any reduction in benefit of ACE inhibitor when used with aspirin. The heart protection study predicted a 44% reduction in cardiovascular events if the effects of statin, aspirin, ACE inhibitor, and blocker treatments were additive. However, the overall effect was only a 24% reduction in major events" ( Lancet 2002:360: 7-22).
He pointed out that gains were likely to be even lower in practice. "Studies consistently show that benefits are less than anticipated when applying treatments in routine practice, due mainly to lack of implementation by health professionals and poor compliance by patients."
He said that the evidence for folic acid was particularly weak.
"Safety is also an important issue, particularly if use of the polypill is being considered for primary prevention in healthy people," Professor Ebrahim said. The original polypill paper predicted that 8% to 15% of people taking the combination would experience adverse effects, largely because of the antihypertensive components. "But statin trials have reported very high levels of side effect symptoms, resulting in discontinuation of treatment," he pointed out.
Looking at the cost effectiveness of interventions for prevention, Professor Ebrahim calculated that the cost of the polypill would be $2600 (￡1460; 2150) per life year gained—higher than for interventions such as lowering blood pressure, exercising, smoking control, or taking aspirin.(Susan Mayor)
Shah Ebrahim, professor of epidemiology of ageing at the University of Bristol, argued that there was only theoretical evidence for the additive effects of the components of the polypill and that it was unlikely to translate into clinical practice.
Speaking at a debate at the recent European Society of Cardiology's annual meeting in Germany, he also argued that there was a risk of serious adverse effects that would reduce long term compliance and so reduce the benefits. Finally, he calculated that the cost effectiveness of the polypill was poorer than that of other preventive options.
Professor Ebrahim was commenting on claims made in a series of papers published recently in the BMJ, including one that said that the polypill could prevent 88% of ischaemic heart disease events and 80% of strokes ( BMJ 2003;326: 1419-24).
The polypill was designed to reduce four cardiovascular risk factors simultaneously: low density lipoprotein cholesterol concentration, blood pressure, serum homocysteine concentration, and platelet function. Its efficacy was quantified from meta-analyses of the effects of the components. It was argued that a third of people taking this pill from the age of 55 would benefit, gaining an average of about 11 years of life free from an ischaemic heart disease event or stroke.
These claims were unlikely to translate into clinical practice, argued Professor Ebrahim. "There is only weak evidence of any reduction in benefit of ACE inhibitor when used with aspirin. The heart protection study predicted a 44% reduction in cardiovascular events if the effects of statin, aspirin, ACE inhibitor, and blocker treatments were additive. However, the overall effect was only a 24% reduction in major events" ( Lancet 2002:360: 7-22).
He pointed out that gains were likely to be even lower in practice. "Studies consistently show that benefits are less than anticipated when applying treatments in routine practice, due mainly to lack of implementation by health professionals and poor compliance by patients."
He said that the evidence for folic acid was particularly weak.
"Safety is also an important issue, particularly if use of the polypill is being considered for primary prevention in healthy people," Professor Ebrahim said. The original polypill paper predicted that 8% to 15% of people taking the combination would experience adverse effects, largely because of the antihypertensive components. "But statin trials have reported very high levels of side effect symptoms, resulting in discontinuation of treatment," he pointed out.
Looking at the cost effectiveness of interventions for prevention, Professor Ebrahim calculated that the cost of the polypill would be $2600 (￡1460; 2150) per life year gained—higher than for interventions such as lowering blood pressure, exercising, smoking control, or taking aspirin.(Susan Mayor)