This is a protocol for a Cochrane Review (qualitative). The objectives are as follows:

1) To assess the various definitions and time points of measurement of hypoglycaemic events in randomised controlled trials (RCT) on long-acting insulin analogues in people with type 1 diabetes mellitus.

2) To assess if the risk estimates of various hypoglycaemic events are identical, and consistently reported in published and unpublished sources.