Seventy-eight studies were included in the review (n=18,288, range 24 to 826 participants; two to 4,956 patient-years).
Combinations of insulin with oral glucose-lowering agents achieved glycaemic control similar to or better than monotherapy insulin, with (in general) less weight gain and lower insulin requirements (13 RCTs).
Rosiglitazone or pioglitazone achieved similar glycaemic control to long-acting insulin, with fewer hypoglycaemic events; both were given in combination with other oral glucose-lowering agents (four RCTs).
Longer-acting insulin analogues (glargine and detemir) achieved similar glycaemic control to NPH insulin, with fewer hypoglycaemic events (14 RCTs); in most of these RCTs both arms also received oral glucose-lowering agents.
In nine of 10 relevant RCTs, premix insulin achieved better glycaemic control than long-acting insulin (with or without oral glucose-lowering agents in both arms); in most of these studies there were more hypoglycaemic events in the premix arms.
Analogue premix insulin achieved glycaemic control equal to or better than human premix, without increased hypoglycaemia rates or weight gain (eight RCTs). No conclusions could be reached about basal-bolus regimens.
Other results were reported in the review.