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Fri May 22, 2009 7:56 am  |
| keli13 wrote: |
Here's a good article about the different retinoids like Taz. They are in the process of testing Taz to see if it really is more effective. In this article they did do one test comparing .05% Retin-A to .1% Taz. Taz did better. I would have liked to see the results if they would have tested the same strength in both products, .1% Retin-A against .1% Taz. Here's the article.
http://www.smartskincare.com/treatments/topical/retinoids.html |
The study the article is quoting is the one carried out by Lowe et al. and published in 2004 in Journal of Cosmetic and Laser therapy.
One of the first problems of the article is that the researchers involved are actually supported by Allergan, and the study was PAID by Allergan the maker of tazorac. So actually if you read the whole article, the "enthusiastic" writing, does not correspond to the results!
In the article, in the discussion section, it says: "The results from this study suggest that tazarotene 0.1% cream offers significant superiority over tretinoin 0.05% emollient cream in the treatment of photodamaged skin". However if you read the results, in reality tazarotene did not actually do better than tretinoin.
In addition, there is a problem with the statistical analysis. They use repeated measures (since they measure the same skin over a period of 24 weeks) but they don't use a repeate-measure analysis... thus their confidence intervals are artificially narrow.
For e.g... let's take the "global improvement" outcome. This score was measured in weeks: 2,4,8,16,20,24. From all those days, only on week 16 there was a "statistically significant" difference between tazarotene and tretinoin. Now... is this difference by chance or a true difference? We can't know since they didn't apply the correct statistical tests. Since there seems to be no trend, it seems that the difference observed at week 16 could have just been an artifact.
For these reasons... we cannot conclude based on this study that tazarotene is superior than tretinoin. |
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37, light brown hair, green eyes, very fair skin. Oily T zone, broken capillaries... Current regime: Tretinoin 0.05% every night, hydroquinone 4% twice per day, lachydran every other day, random moisturizers and sunscreen |
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