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The authors conclude: "This current systematic review highlights the shortcomings in the published trials of statins for primary prevention. Selective reporting and inclusion of people with cardiovascular disease in many of the trials . . . in previous reviews of [statins'] role in primary prevention make the evidence impossible to disentangle without individual patient data."
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2 R7 m8 n) R; u+ hThey say that in people at high risk of cardiovascular events (>20% 10-year risk), "it is likely that the benefits of statins are greater than potential short-term harms, although long-term effects (over decades) remain unknown." They conclude: "Any decision to use statins for primary prevention should be made cautiously and in the light of an assessment of the patient's overall cardiovascular risk profile. Widespread use of statins in people at low risk of cardiovascular events—below a 1% annual all-cause mortality risk or an annual CVD event rate of below 2% observed in the control groups in the trials considered here—is not supported by the existing evidence." " x' _- _4 T" t* ]3 y% N
Latest Oxford meta-analysis not included ) t o n+ W* Q' u( K( K+ T
The Cochrane review did not include the recent meta-analysis from the Oxford group, published late last year, which showed a clear reduction in events with statin therapy in primary-prevention patients. Baigent noted that this meta-analysis was more reliable than the Cochrane review, as the Oxford researchers used individual patient data from all the trials. "Our 2010 meta-analysis in primary prevention is substantially more complete than the Cochrane review and provides direct and overwhelmingly statistically convincing evidence of a clear reduction in events in all patient groups, right down to those at the lowest risk."6 p0 i* b; a, m4 F1 d
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On the possible hazards of taking these drugs, Baigent says: "Statin therapy is very safe. The most serious hazard, rhabdomyolysis, is very rare, and most often seen at high doses. There is a possibility that reducing LDL cholesterol might increase the risk of hemorrhagic stroke, but even in primary prevention these hazards would be much smaller than the benefits, and there is no reliable evidence for other hazards mentioned by the Cochrane authors, such as depression and cognitive impairment."
: S/ u# r& K( Y' s, {' BIt all comes down to economics - c G1 K" e$ k/ c! u
Baigent says the only argument against using statins in low-risk people is economic. "The absolute benefits of statin therapy become very small when used among people at low absolute risk, so it is important that the costs of such treatment are considered when weighing how widely statins should be used. That is a government decision."
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In the UK, the National Institute for Clinical Excellence [NICE] currently recommends that statins not be used for people with a CHD risk below 20% over 10 years. Ebrahim says the Cochrane conclusions are in line with this.
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) w1 S+ m; N( {' B8 F1 `% MBut Baigent argues that the benefits of statins are clear at levels far below this threshold. "Whether or not it is economic to use them in the lowest-risk individuals is not for me to say, but generic statins are now very cheap, and there is clear evidence of benefit and safety based on substantial numbers of individuals studied in large-scale trials. So, when all the relevant randomized evidence is considered, there does not seem to me to be any justification at all for the Cochrane authors' claim that the evidence is unclear on this issue."
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Educational programs also of little benefit
2 a# V9 V0 W6 AIn a separate Cochrane review [2], the same group looked at the use of "healthy heart programs" that use counseling and educational methods to encourage people to reduce their risks for developing heart disease. These risk factors include high cholesterol, excessive salt intake, high blood pressure, excess weight, a high-fat diet, smoking, diabetes, and a sedentary lifestyle. They reviewed 55 trials that aimed to reduce more than one risk factor in people without evidence of cardiovascular disease. Results showed that after a median duration of 12 months of follow-up, multiple risk-factor intervention was associated with small reductions in risk factors, including blood pressure, cholesterol, and smoking, but had little or no impact on the risk of coronary heart disease mortality or morbidity. They conclude: "The methods of attempting behavior change in the general population are limited and do not appear to be effective. Different approaches to behavior change are needed and should be tested empirically before being widely promoted, particularly in developing countries where cardiovascular disease rates are rising."
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, `& I$ X) K! `& MIn an accompanying editorial [3], Dr Carl Heneghan (University of Oxford, UK) suggests an alternative approach for policy is to focus on populationwide prevention. He reports that "legislating for smoke-free public spaces, redesigning public spaces to improve exercise, or reducing daily dietary salt intake prove generally effective and can be cost-saving interventions. Given the scale of the worldwide CVD problem, large-scale commissioned studies of multiple risk-factor interventions are urgently required."
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+ P1 G [( o0 M \Taylor F, Ward K, Moore THM, et al. Statins for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev 2011; 1 (CD004816).
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: S5 S& e) V9 p2 m7 ]Ebrahim S, Taylor F, Ward K et al. Multiple risk factor interventions for primary prevention of coronary heart disease. Cochrane Database Syst Rev 2011; 1 (CD001561).
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Heneghan C. Considerable uncertainty remains in the evidence for primary prevention of cardiovascular disease [editorial]. Cochrane Libr 2011 (January 19, 2011). Available here. ) ~8 e9 j3 c. r; Z
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) V! i p5 W5 V- ~8 c6 ihttp://news.dxy.cn/bbs/topic/19443789 x9 z" U4 X9 @1 U" k
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