Identifying metabolic risk patterns over time is critical to predicting progression from prediabetes to diabetes. This retrospective cohort analysis evaluated the relationship between baseline AIP, longitudinal AIP trajectories, and diabetes progression in individuals with prediabetes.

The study included 16,411 adults with prediabetes who completed three or more health examinations between 2019 and 2024. During a mean follow-up of 4 years (65,644 person-years), 2,320 individuals (14.14%) progressed to diabetes. Latent Class Trajectory Modeling identified three AIP trajectory groups: low plateau (N = 4,422; 26.95%), medium decreasing (N = 8,183; 49.86%), and high decreasing (N = 3,806; 23.19%).

Compared with the low plateau trajectory, the medium decreasing group showed a higher adjusted diabetes risk (hazard ratio [HR] 1.42; 95% confidence interval [CI] 1.22–1.65), and the high decreasing group showed the highest adjusted risk (HR 2.26; 95% CI 1.81–2.83). A graded association was also observed across baseline AIP quartiles.

The findings demonstrate that baseline AIP and unfavorable AIP trajectory trends are strong indicators of diabetes progression in prediabetes. Longitudinal AIP assessment may help identify individuals requiring more intensive preventive strategies.