Wednesday, July 12, 2006

Still more on LABAs, asthma and the Annals meta-analysis

I was eagerly awaiting the replies to the recent Salpeter meta-analysis (MA) posted about here.

I suspect the rapid responses are available only by subscription, so here are some of the critical comments paraphrased:

1.The MA was basically a warm over of the SMART trial since about 3/4 of the data in the MA was derived from SMART and apparently all of the mortality data. I have commented before on the inadequacies of the SMART trial and how it may well be a poster child for how not to do a large RCT.

2.Since SMART was not able to answer the big question (i.e does the use of inhaled corticosteroids (ICS) protect from any putative harm derived from the LABAs),neither can a MA based largely on SMART. There was a one sentence summary in the analysis section that purported to show that ICS were not protective but no tabular data was presented and a conclusion that important should have been explicated further.

3.Salpeter's recommendation of inhaled anti-cholinergics to replace LABAs in asthma treatment was ill-advised as there are no clinical trial data showing its efficacy and safety in asthma treatment (as opposed to COPD treatment).

4.Concern was expressed that patients would be stopping their LABAs on their own based on the lay press's reporting of this article.One group of letter writers said exactly that had happened with the resultant exacerbation of patients symptoms.

5.Salpeter's comment that 4,000 of the 5,000 U.S.Asthma deaths per years could be blamed on LABAs was criticized by several letters.Two writers commented that the CDC data indicate that in 1996 asthma deaths were about 5,600 and by 2,003 ( the last year for which data is available) it had decreased to about 4,800. Salmeterol was introduced in the U.S. in 1994. Although this data does not at all prove salmeterol introduction decreased asthma deaths it is consistent with that interpretation and does not support the opposite conclusion. But, in any event the comment that 80% of asthma deaths are due to LABA is unwarranted hyperbole at best.Another letter supplied British data also showing a decrease in asthma deaths in the era following the intoduction of a LABA.

Just as the controversy over the Salpeter article grows, even more disagreement is likely to be generated by a recent article by the Salpeter father and daughter combo concluding that LABAs and short acting beta-agonists also increase the mortality in patients with COPD.

No comments: