Risk of cardiovascular disease and all cause mortality among patients with type 2 diabetes prescribed oral antidiabetes drugs: retrospective cohort study using UK general practice research database

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 if a different temporally cohort from the other treatment
cohorts. Has this been considered in the analysis ? Could a reanalysis 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.

Competing interests:
None declared