INS and diabetes mellitus: An alternative approach would have been to model differences between people with and without diabetes directly within each trial, but at the price of excluding these five trials.w1-w3 w29 w33 A final limitation of our study is that we were unable to record information on specific antidiabetic treatment or on glycaemic control in people with diabetes mellitus and to perform separate analyses for people with diabetes who did or did not use insulin.