Is adherence to the alternate healthy eating index an effective approach for prediabetes reversion? A longitudinal follow-up

We investigated the potential effect of adherence to a healthy diet on the probability of reversion to normal glucose regulation (NGR) among different phenotypes of prediabetes (Pre-DM), a heterogeneous metabolic disorder affecting glucose metabolism, i.e., isolated impaired fasting glucose (i-IFG; fasting glucose 100-125 mg/dL with normal glucose tolerance), isolated impaired glucose tolerance (i-IGT; 2-h post-load glucose 140-199 mg/dL with normal fasting glucose) and combined IFG-IGT (meeting both criteria).

Adherence of 1456 individuals with Pre-DM to a healthy diet was assessed using the Alternate Healthy Eating Index (AHEI) at baseline, and the participants were followed for a median of 5.8 years. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95 % confidence intervals (CIs) for Pre-DM reversion to NGR across the categories of adhering to AHEI (i.e., low and high-adherence of AHEI) and per each 10-increment of AHEI. The estimated time to Pre-DM reversion was compared among low- and high-adherence to AHEI using a log-rank test.

The mean age of the participants was 47.2 ± 12.8, and 52.5 % were men. Overall rate of Pre-DM reversion was 46.8 %, with rates of 53.6, 55.1, and 15.7 % in i-IGT, i-IFG, and IFG-IGT, respectively. After adjustment of diabetes risk score, high-adherence to AHEI increased the probability of a reversion to NGR, HR = 1.31, 95 % CI = 1.13-1.51. Considering Pre-DM phenotypes, subjects with combined IFG-IGT showed a greater benefit from high adherence to AHEI compared to those with isolated phenotypes, HR = 2.33 and 95 % CI = 1.27-4.30. Furthermore, the mean of estimated time to reversion to NGR from IFG-IGT showed a marginally significant trend toward being shorter, 6.2 y (5.1-6.2) vs. 8.4 y (8.0-8.8) and P_log-rank = 0.051.

Adherence of individuals with Pre-DM to healthy diet effectively increased the probability of reversion to NGR, and the observed effect was stronger in subjects with combined IFG-IGT than the isolated phenotypes.