['This study clarified whether detrended fluctuation analysis (DFA) can evaluate how to advance the loss of complexity from impaired glucose tolerance (IGT) through mild diabetes mellitus (DM) to overt DM.', 'Continuous glucose monitoring (CGM) was done during a 48-h interval for 59 subjects from multiple centers. Subjects were divided according to CGM data into those with impaired glucose tolerance (IGT) (n = 20), mild DM (n = 13), and overt DM (n = 26). The short-term (α1) and long-term (α2) range exponentials by DFA were compared among the three groups.', 'The value of α1 within 1h was significantly lower in the IGT group than in either of the other two groups (IGT vs. mild DM vs. overt DM, 1.53 ± 0.22 vs. 1.71 ± 0.17 vs. 1.77 ± 0.13, P<0.0001), and α1 within 2h differed significantly among the three groups (1.49 ± 0.13 vs. 1.57 ± 0.10 vs. 1.72 ± 0.10, P<0.0001). The α1 within 3h was significantly higher in overt DM than in either of the other two groups but did not change between IGT and mild DM (1.44 ± 0.12 vs. 1.52 ± 0.11 vs. 1.67 ± 0.09, P<0.0001). All short-term exponents decreased gradually but significantly as the window widened in all groups (P<0.0001). The α2 over 1h was significantly higher in overt DM but was unchanged in IGT and mild DM (1.22 ± 0.11 vs. 1.27 ± 0.12 vs. 1.36 ± 0.13, P = 0.0010). The α2 over 3h did not differ among the three groups.'] Is detrended fluctuation analysis considered to be useful as a new indicator for short-term glucose complexity?