Useful Links - these seem good but everybody plays with data and statistics so be smart and vigilant


In previous podcasts, you all have denounced beta blockers as antihypertensives of little POEM value. Some true experts, at least expert in clinical epidemiology, recently published a "giant" metaanalysis and concluded that beta blockers (presumably including atenolol) are equal to other antihypertensives. Here's the reference: Law MR, Morris JK, Wald NJ. Use of blood pressure lowering drugs in the prevention of cardiovascular disease: meta-analysis of 147 randomised trials in the context of expectations from prospective epidemiological studies. BMJ. 2009 May 19;338:b1665. doi: 10.1136/bmj.b1665. (Review) PMID: 19454737

After you have had a chance to read the impressive article, I wonder if you still conclude we should eschew beta blockers.

As you industriously rack up more and more podcasts, I'm finding the design of the podcast web pages on this site limits my ability to quickly find an episode which I recall has addressed an issue I'm interested in revisiting. For an issue addressed early on, there's quite a lot of bac-paging to do - frustrating if I've got a particularly slow connection.

I wonder if you would consider condensing the index to just the numbered title of each podcast in a smaller font on a single scrollable page for quick reference?

Keep up the great work. My most enjoyable form of CME - true infotainment!

RSS feed in firefox works well for this. Click on you guys and all podcasts are listed.

Hi! I am a nurse practioner student. I love listening to your podcasts! Could you please present a podcast on contraceptives? Keep the podcasts coming! PS When speaking about various drugs could you please tell what they are? Being a student, I'm still learning them!

Hi Brian: Thanks for your comment - first off, I don't believe we "denounced" beta-blockers but rather stated the evidence wasn't as convincing for this class of drugs compared to others. I had seen this meta-analysis and it really didn't change my conclusion on atenolol or beta-blockers in general. Here is my reasoning and it is based on looking at the actual data rather than the "true experts" interpretation.

1) in regard to atenolol the authors state “The relative risk estimate from a previous analysis of four blood pressure difference trials of atenolol of 0.99 (95% confidence interval 0.83 to 1.19) was revised to 0.93 (0.75 to 1.14) in our analysis with the inclusion of two additional atenolol trials”.
So what we have are two studies added to the four from a previous analysis that we reported on and still atenolol has yet to show a statistical reduction in clinical endpoints - the risk estimate (0.75 to 1.14) clearly includes 1. Based on this, I still conclude atenolol, despite the fact it lowers blood pressure, has not been shown to reduce cardiovascular events. Other drugs HAVE shown a benefit in reducing cardiovascular events.
2) in regard to other beta-blockers, these authors, in contrast to other published meta-analyses, included trials which would be considered more like secondary prevention trials as many patients had a history of CHD – this could have an impact on the outcome. Nonetheless, figure 1 shows beta-blockers as the only class of drugs not showing a statistical reduction in CHD (although the upper end of the confidence interval is just 1.02). In addition, compared to calcium channel blockers and diuretics, stroke reduction was close to being statistically different in favour of these two agents over beta-blockers and in fact in figure 3, betablockers versus all other agents were statistically inferior when it came to stroke reduction.
Based on the above, I still think the evidence for reducing CVD events is general weaker for beta-blockers than for other drugs, and we still have no evidence that atenolol reduces CVD events. But clearly data interpretation is in the eye of the beholder and I would be more than happy to hear how you would interpret this evidence.

Hope this helps and thanks for listening to our podcast.