TODAY2 Phase 1 Immediate Post-Intervention Observational Follow-up Study

The primary objective of the first phase of TODAY2 is to begin to examine the persistence of effects of the TODAY treatment assignment on long-term glycemic control following discontinuation of randomized treatment. During this period, results of TODAY are produced and used to define additional outcomes for the second phase of TODAY2.

HbA1c is the designated measure of glycemic control during T2P1. Mean HbA1c levels for participants from the three original TODAY treatment arms are compared as measures of the degree and durability of glycemic control after discontinuation of initial randomized therapy. The overall target is to maintain HbA1c levels as close to the normal range as possible in order to reduce long-term diabetes complications. TODAY2 continues to use HbA1c < 6% as the target.

In TODAY2, subjects are treated with approved medications, i.e., metformin and/or insulin. No specific abnormalities are expected to develop in this cohort, given the well-documented safety record of these agents. However, abnormalities in laboratory tests (hemoglobin/hematocrit, liver function tests, calculated creatinine clearance), episodes of severe hypoglycemia, and incidence of side effects (e.g., gastrointestinal complaints) are tracked.

An important component of TODAY2 is to continue to monitor insulin sensitivity and secretion in the TODAY cohort after discontinuation of randomized therapy to determine (1) the evolution of changes in insulin secretion and sensitivity as participants emerge from puberty and enter young adulthood and (2) the effect of each of the initial therapies on the progression of changes in insulin sensitivity and secretion.

Insulin sensitivity and secretion are determined with fasting glucose, insulin, C-peptide, and proinsulin levels, OGTT-based indices, HOMA, and QUICKI measured annually.

Both traditional and non-traditional CVD risk factors are measured in the first phase of TODAY2 and assessed overall as well as compared across initial treatment arms. Blood pressure is measured at every visit and specimens drawn annually for repeated measurements of lipids (free fatty acids, lipoprotein subclass levels, average LDL particle density, and total apoB level), fibrinogen, c-reactive protein, plasminogen activator inhibitor-1, homocysteine (vitamin B-12 to evaluate homocysteine levels), and interleukin-6.

Quantitation of microalbuminuria is performed by obtaining spot urine measurements of microalbumin/creatinine ratio at annual visits. Abnormal values are confirmed with two additional samples within three months; diagnosis of microalbuminuria is made as a result of two out of three positive tests. Creatinine clearance (by calculation) is determined at annual visits.

The presence of peripheral neuropathy is evaluated using the Michigan Neuropathy Screening Instrument (MNSI) performed annually.