Complex sentence: Reports in 2001 linked the thiazolidinediones (the class of drugs to which rosiglitazone belongs) to heart failure, and in 2005 and 2006 two GSK meta-analyses of randomized trials of rosiglitazone showed an increased risk of adverse cardiovascular outcomes.
Split into simpler sentences: Reports in 2001 linked the thiazolidinediones (the class of drugs to which rosiglitazone belongs) to heart failure. In 2005 and 2006 two GSK meta-analyses of randomized trials of rosiglitazone showed an increased risk of adverse cardiovascular outcomes.