New cholesterol guidelines

  1. bohm2

    bohm2 809
    Gold Member

    Just looking at the new guidelines, it seems that prescriptions for statins are going to increase above the already very high level:
    New Guideline for Management of Blood Cholesterol: Focuses On Lifestyle, Statin Therapy for Patients Who Most Benefit
    http://www.sciencedaily.com/releases/2013/11/131112163210.htm
     
  2. jcsd
  3. bohm2

    bohm2 809
    Gold Member

    A criticism of the calculator to estimate 10-year risk of cardiovascular disease: http://my.americanheart.org/profess...vention-Guidelines_UCM_457698_SubHomePage.jsp has just been published in Lancet by Drs. Ricker and Cook:
    Statins: new American guidelines for prevention of cardiovascular disease
    http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(13)62388-0/fulltext
     
  4. The big change seems to have come from the Cholesterol Treatment Trialists (CTT) study published in The Lancet last year. The issue with this study is the denominator – they looked at the effect on cardiovascular risk per unit LDL reduction. The risk of using this denominator is that there’s no way to calculate an NNT for statins – they potentially excluded those that are on a statin with minimal LDL reduction, but included those on a statin that may have lowered their LDL thru other means.
     
  5. Could you please provide a link for these assertions. The Lancet article was regarding a meta-analysis of 27 trials which showed actual reductions for cardiovascular events. More importantly, it showed equivalent reductions in both low risk and high risk categories. I saw no data on "number needed to treat" (NNT) but it could be inferred from the consistency of risk reduction across low to high risk categories. The reduction in LDL-C was another analysis.

    I would be interested in any critique of these findings. The issue would be with the meta-analysis rather than the trials themselves since there are still some issues with the methodology of meta-analysis. I look forward to your link. The reduction of LDL-C is well established for statins as a class.

    http://www.ncbi.nlm.nih.gov/pubmed/22607822
     
    Last edited: Nov 27, 2013
  6. bohm2

    bohm2 809
    Gold Member

    I think the problem here is confounding factors. There are other cholesterol medications like Ezetimibe (Ezetrol) that reduce LDL (whether as monotherapy or in combination with a statin) but have no effect on overall or cardiovascular mortality. For example, have a look at the Enhance trial.

    Simvastatin with or without Ezetimibe in Familial Hypercholesterolemia
    http://www.nejm.org/doi/full/10.1056/NEJMoa0800742

    In fact, there was a slight increase (not significant) in cardiovascular events and plaque formation (as measured by carotid artery intima-media thickness) when Ezetrol was combined with a statin despite a statistically greater reduction in LDL. To me, this implies that it may not be only the LDL reductions that give statins the benefits. It may the result of anti-inflammatory properties, etc. (as also acknowledged by the authors). So, on the one hand, I like the fact that there isn't this obsession achieving LDL targets, but at the same time I think the risk calculator is a problem. You can play around with it and some have and here's an interesting finding one physician noted:
     
    Last edited: Nov 27, 2013
  7. While I agree that inflammatory processes indicated by elevated levels of C-reactive protein are correlated with risk, the 27 studies in question were randomized trials which makes it unlikely that true confounding is present. As I said, if there is to be a challenge to the interpretation of the meta-analyisis, I think one has to look at the details of the meta-analysis itself in terms of the methodology used to combine data from different studies.
     
    Last edited: Nov 28, 2013
  8. bohm2

    bohm2 809
    Gold Member

    Criticism has been made that the risk calculator overestimates risk in some groups:
    How Good Is the New ACC/AHA Risk Calculator?
    http://www.medscape.com/viewarticle/814579
    What is interesting and not consistent with the C-reactive protein/anti-inflammatory hypothesis is that in the Enhance trial, the ezetrol + statin group vs statin alone group there was a significantly greater reduction in C-reactive protein (-49% vs -29%) and yet there was no cardiovascular benefit.
     
    Last edited: Nov 28, 2013
  9. This trial is controversial. In any case, it studied the potential benefit of this drug combination in cases of familial hypercholesterolemia. I'm not sure how you compare this result with those in subjects without this condition and taking only a statin.

    http://www.medscape.com/viewarticle/568763

    Regarding the accuracy of the risk calculator, I have no comment. I was only addressing the important point of risk reduction in low risk subjects. If the risk calculator is in fact overestimating risk, it only enhances the finding of efficacy in "low risk" subjects. If the calculator is over estimating risk (and the proposed calculator is the one used in the meta-analysis) than "low risk" subjects should have had even lower risk.
     
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