Table 7.

Change in HbA1c from time of glycemic failure/study midpoint cutoffs, area under the curve (AUC) and its 95% Wald CI, within 3, 6, 9, and 12 months of glycemic failure/study midpoint*

Groups	N	Change in HbA1c cutoff	AUC
Within 3 months	493	+0.6	0.97 (0.95-0.98)
Within 6 months	470	+0.8	0.91 (0.89-0.94)
Within 9 months	431	+0.6	0.92 (0.89-0.95)
Within 12 months	409	+0.7	0.96 (0.94-0.98)

*Not all the n = 584 participants included in the analysis (n = 174 without loss of glycemic control during 2004-2014 plus n = 410 with loss of glycemic control during 2004-2014; Figure 1) had an HbA1c collected within 3, 6, 9, or 12 months relative to their time of failure or study midpoint (eg, n = 493 within 3 months, n = 470 within 6 months). For participants who lost glycemic control (ie, reached glycemic failure), change in HbA1c is defined as the difference between HbA1c values collected at a given time point prior to failure and the time point when failure was reached (eg, within 3 months of glycemic failure); for participants who did not lose glycemic control during 2004-2014, change in HbA1c is defined as the difference between HbA1c values collected at a given time prior to the participant’s midpoint in the study and the participant’s study midpoint. AUC is a measure of diagnostic accuracy ranging from 0 to 1, with AUC values > 0.9 indicating very good ability to predict glycemic failure.