A response to this article from a GP.
Pioglitazone was launched in 2000 . It seems unlikely to have been widely used till 2002-03. Yet this study ran from 1990 till 2005. During this period mortality from vascular disease fell sharply by about a third.
This study is confounded by this effect of time , the pioglitazione treatment group is a different temporally cohort from the other treatment cohorts. Has this been considered in the analysis ? Could a re-analysis of all the data from only 2000 onwards be done ? Also, this might account for the negative outcome of Sulphonylureas which during the 1990s were the most widely used medications but then fell from favour. Observation is not always causation.