Metformin and Transient Hyperglycemia

ALL is the most common childhood cancer, representing one fourth of all cancers diagnosed under the age of 15 years. One of the most common side effects of ALL chemotherapy is transient hyperglycemia. Patients that develop this complication require treatment with insulin via injections to prevent severe medical complications such as dehydration, weight loss, ketoacidosis and life-threatening infections. Although insulin therapy is effective, it adds a lot of physical and psychological burden to patients because multiple daily insulin injections are required to achieve adequate blood glucose control. In this pilot study, investigators aim to examine the effectiveness of metformin as an adjunctive treatment for transient hyperglycemia. Investigators will be comparing two groups of subjects (up to 40 subjects per group). Patients in the treatment group will be prospectively recruited, and they will be treated with metformin in addition to insulin therapy. Investigators will compare the treatment group to a historical control group acquired via chart review. These patients will have been treated with insulin alone. Statistical comparison will be made between the two groups in terms of the length of insulin treatment, the total daily dose of insulin required, number of insulin injections, hemoglobin A1c level (measure of glycemic control over preceding 8- 12 weeks), and fructosamine level (measure of glycemic control over preceding 2-3 weeks). Investigators hypothesize that the use of metformin will result in fewer numbers of insulin injections and fewer days of insulin therapy.