LADA is a condition that at diagnosis looks like type 2 diabetes (non-insulin requiring diabetes mellitus) but actually is a type 1 diabetes, where the patient will become insulin requiring. In the UK approximately 3.6% of people who look like they have type 2 diabetes actually have type 1 diabetes, while other studies suggest the prevalence is higher and treatment for these patients may need to be different from that used in type 2 diabetes.
We identified 15 publications (10 studies) looking at 1019 patients who were followed between three months to 10 years. We found many of the publications had poor quality of reporting and had small numbers of participants. However, there does seem to be evidence from this review that the drug sulphonylurea (like glibenclamide or glyburide, gliclazide) could make patients insulin dependent sooner and it does not control blood sugar as well as insulin. Therefore, this suggests that this drug should not be a first line treatment for patients with LADA. In addition, insulin combined with vitamin D, or Chinese herbs may maintain natural insulin production better than insulin alone. Similarly, glutamic acid decarboxylase (GAD65) may maintain natural insulin production. However, there was no conclusive evidence that any of the other remaining treatment methods were better than each other. Studies on oral agents or insulin reported no adverse events in terms of severe hypoglycaemic attacks.
This review represents very early days of our understanding of the best way to treat LADA. It is limited by the poor reporting quality of the studies, small sample sizes, no clear single definition of LADA and many of the studies being carried out in different ethnic groups (China, Japan, Cuba, UK, Sweden) with different clinical care systems.
None of the publications reported on complications of diabetes, health-related quality of life, costs or health service utilisation. All but one of the publications reported there were no deaths.
In summary, this review demonstrates that insulin treatment may be preferable compared to sulphonylurea treatment but there is little evidence regarding other forms of treatment. Future studies are needed, should have a clear definition of LADA, investigate patient-important outcomes and use a common method of measuring stimulated C-peptide (a marker of natural insulin production reflecting improved beta-cell function of the pancreas).