Tuesday, January 20, 2009

Clearly there is no end to the postive benefits for statins-the list goes on and on

I have written several times before expressing my amazement at the ever growing list of positive medical benefits that the statin group of drugs are said to bestow.

Here is a reference to a review that concluded there can be a significant reduction in the onset of atrial fibrillation with statin use. Here is reference to another review that analyzed the course of over 30,000 patients and found a 43% reduction in death following heart surgery for those given pre-op statins. And it seems good not just to prevent death, here is reference to an article from Canada that found a reduction in post-op delirium of almost fifty percent from statin use.

Of course, there are always doubters. Intrigued by observational reports that statin users were at lower risk from sepsis and were less likely to die from sepsis if they developed it, a group from Canada did their own investigation and failed to confirm a mortality benefit and offered the argument that, at least, in some of the observations studies that concluded a benefit in disease X, Y or Z from statin use that we were seeing our old friend , the healthy user effect.

With case controls studies and observational data analyses, all sorts of correlations will emerge, some of which will suggest negative effects of a medication. You have to wonder how many data dredging exercises with negative results never see the light of a published page . However,some have been reported in regard to statins. For example, a study from France raised the possibility of tendon damage from statin use. See here for earlier comments on that.There was also concern expressed about a possible association with statin use and risk of Parkinson Disease.

There is at least one disease in which statins may not be beneficial.This report suggest adding statins to inhaled steroids for asthma did not seem to help.

Sometimes, the magnitudes of the reported benefit are neuron boggling such as this report of a case control study that demonstrated an 83% reduction in death from COPD in statin users. The sicker COPD patients have lower and often quite low LDL levels and would be very unlikely candidates to have been treated with a statin in the first place and the healthier patients with airways obstruction were more likely to be treated to lower their LDL. We may have here not only a "healthy user " effect but an "unhealthy nonuser effect" which is one of the problems of working with "coarse grained data". When something seems to good to be true...

I like to call observational studies coarse-grained instruments with bias and confounding being the basis for the coarseness as well as often a dearth of patient specific data These hidden variables may lead to an association that is not real. We can only be confident that the calculated confidence interval takes only random variation in the data into account . It does not fix everything. Various types of bias and confounding are beyond its command,a point rarely made in the press blurbs about various benefits and harms of medical interventions.

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