Type 2 diabetes is a progressive disease and, despite recent progress in the treatment of diabetes, the glycemic control usually deteriorates gradually and insulin therapy is needed. When insulin therapy should be started and which are the appropriate insulin therapy strategies, still represent subjects of debates. Insulin represents a therapeutic option in type 2 diabetes due to the existence of early β-cell dysfunction and significant reduction of β-cell mass in natural history of type 2 diabetes. The current guidelines recommend insulin in double therapy in association with metformin or in combination with metformin and other noninsulin agent. Initiation of insulin therapy is recommended in patients with newly diagnosed type 2 diabetes and symptomatic and/or presenting important hyperglycemia or elevated HbA1c. Initiation of insulin therapy in type 2 diabetes should take into consideration the pathophysiology of type 2 diabetes, the effects and the potential risks of insulin therapy, the guidelines recommendations and the barriers to insulin use. Literatures of only English language were analyzed from NCBI database. Guidelines were accessed electronically from organisations, i.e. American Diabetes Associations, American Association of Clinical Endocrinologists and American College of Endocrinology, European Association for the Study of Diabetes, International Diabetes Federation.
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