Aim: This study aimed to identify the patterns of changes in glycemic indices over time in prediabetics and to classify these subjects as either having a high or low risk for developing diabetes in future.

Methods: This prospective 16-year cohort study was conducted among 1228 prediabetic subjects. Three measurements including first visit, mean values during the follow-up period, and last visit from fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1_C), and area under the curve during an oral glucose tolerance test (OGTT AUC) were used to evaluate the patterns of changes by using the latent Markov model (LMM).

Results: The mean (standard deviation) age of subjects was 44.0 (6.8) years, and 73.6% of them were female. The LMM identified 2 latent states of subjects in terms of changes in FPG, HbA1c, OGTT AUC, and the combination of these glycemic measures: a low tendency to progress diabetes and a high tendency to progress diabetes with the latent state sizes (87, 13%), (94, 6%), (57, 43%), and (84, 16%), respectively. The LMM showed that the probability of transitioning from a low tendency to a high tendency to progress diabetes was higher than the probability of transitioning in the opposite direction.

Conclusion: Based on a long-term evaluation of patterns of changes in glycemic indices, we classified prediabetic subjects into 2 groups (high or low risk to progress diabetes states in future). Also, the method used enabled us to estimate the transition probabilities from low- to high-risk states and vice versa. Our results reemphasized the values of all 3 glycemic measures in clinical settings for identifying prediabetic people with a high risk of progressing diabetes and the need for more effective prevention strategies, which should be conducted as urgently in prediabetic life as high-risk subjects.