Comments for Morsels of Evidence

Comment on Cranberry juice fails for urinary tract infections by Michael Tam

Michael Tam — Fri, 19 Aug 2011 01:15:10 +0000

I now have a regular column, Examining the Evidence in Medical Observer, a weekly general practice news magazine. My first article was published on 16 August 2011, "Can cranbery prevent UTIs?". The simplified critical appraisal was on this article.

Comment on Inhaled corticosteroids as rescue treatment by Michael Tam

Michael Tam — Thu, 05 May 2011 12:38:58 +0000

There have been many previous studies looking at the effect of asthma and inhaled corticosteroids on growth. A neat little summary here:

Pedersen S. Do inhaled corticosteroids inhibit growth in children? Am. J. Respir. Crit. Care Med. 2001; 164(4); 521-535
http://ajrccm.atsjournals.org/cgi/content/full/164/4/521

Comment on Inhaled corticosteroids as rescue treatment by Joel Rhee

Joel Rhee — Wed, 04 May 2011 22:36:14 +0000

A bit worried about the 1.1cm drop in growth in under a year… a longer follow up would have been useful to see whether many of the affected children will then have a ‘catch up’ growth to make up some of this difference.

Comment on Incidence and progression of thyroid dysfunction in elderly by Michael Tam

Michael Tam — Fri, 25 Feb 2011 00:18:41 +0000

This was not done in this study but I’m pretty sure that there is pre-existing evidence that demonstrates that autoantibodies are predictive.

Comment on Incidence and progression of thyroid dysfunction in elderly by Joel Rhee

Joel Rhee — Fri, 25 Feb 2011 00:05:47 +0000

I haven’t yet read the article but I wonder whether they checked a person’s thyroid autoantibody status to see whether this was predictive of progression to overt hypothyroidism…

Comment on Omega-3 fatty acids for prevention of atrial fibrillation by Juliana Andrici

Juliana Andrici — Sun, 20 Feb 2011 12:30:52 +0000

With regards to the first symptomatic episode of AF, the article mentions that the participants were subject to “biweekly transtelephonic
monitoring” to document asymptomatic recurrences of AF and assess
symptomatic events. No more detail is given, so presumably it was based on patient assessment of symptoms.

Comment on Omega-3 fatty acids for prevention of atrial fibrillation by Michael Tam

Michael Tam — Fri, 18 Feb 2011 02:11:51 +0000

I have to read the study again, but I think the patients had an electrocardiographic review that was “transtelephonic” twice weekly, and a diary to record whether they had any symptoms suggestive of reversion to atrial fibrillation. Although I agree with your criticism regarding “symptoms”, the study design does have greater internal validity for demonstrable AF rather than “palpitations”.

I hadn’t though about the intent of the study from that point of view but I somewhat concur. I feel that the study authors were hoping to demonstrate that omega-3 fatty acids may have a physiological effect on atrial fibrillation; and to demonstrate it in a clinical trial. I agree that this RCT may not have been the best study design for demonstrating physiology. This is a limitation of industry funded studies I suspect!

Comment on Omega-3 fatty acids for prevention of atrial fibrillation by Joel Rhee

Joel Rhee — Thu, 17 Feb 2011 22:57:13 +0000

An interesting article and a lot of thoughts popped into my head as I was reading this.

I am not too sure about the point of the study given that we already know that rhythm control strategy is not worthwhile pursuing for AF except in certain situations – for instance, when AF causes hemodynamic compromise or triggers acute cardiac decompensation; when AF causes reduction in exercise tolerance often in younger patients; or when AF causes too much symptoms despite adequate rate control.

I am not sure how they measured or defined the first symptomatic episode of AF. Was it when patient felt a bit odd? Was it when the patient required a visit to ED because they became acutely unwell?
If the intent of the study was to investigate whether omega 3 fatty acid can result in symptomatic (thus subjective) improvement, then shouldn’t they have done this in a survey format asking patients whether they feel that their palpitation and exercise tolerance has improved as a result of whatever medication they were taking?

Given that the risk of stroke (the more important and feared consequence of AF) seems to be more or less the same in paroxysmal AF that is not rhythm controlled vs paroxysmal AF that is rhythm controlled; and that the risk of stroke does not seem to differ whether the AF is paroxysmal or it is persistent, the focus on AF should be on anticoagulation.

On this note, BAFTA study, a RCT that was published a couple years ago studied older patients in a general practice setting in the UK and showed that anticoagulation in AF (whether paroxysmal or persistent) was both safe (in fact, safer than Aspirin), and effective (more effective than aspirin).

Comment on Cryotherapy vs topical salicylic acid for cutaneous warts by Michael Tam

Michael Tam — Tue, 08 Feb 2011 11:39:22 +0000

Perhaps you were thinking of the Cochrane Library systematic review on topical treatments for cutaneous warts?

Gibbs S, Harvey I. Topical treatments for cutaneous warts. Cochrane Database of Systematic Reviews 2006, Issue 3. Art. No.: CD001781.

http://dx.doi.org/10.1002/14651858.CD001781.pub2

The review was limited by the lack of quality studies of cryotherapy.

Comment on Glucosamine and/or chondroitin for osteoarthritis by Michael Tam

Michael Tam — Tue, 08 Feb 2011 11:30:38 +0000

Stratified analysis compared between glucosamine sulphate and glucosamine hydrochloride and no significant difference was found between the two.

Specifically: difference in means on 10 cm visual analogue scale (95% confidence interval):
- glucosamine sulphate: -0.5 cm (-0.7 to -0.2)
- glucosamine hydrochloride: -0.1 cm (-0.8 to 0.7)

That is, the results for glucosamine sulphate only were similar to the combined result for glucosamine. Even if the actual effect was at the upper limit of difference in the confidence interval (-0.7 cm), it still remains below the accepted level of clinical significance.