Abstract: Objective To explore the interaction effects of serum levels of γ-aminobutyric acid(GABA) and insulin-like growth factor-1(IGF-1) on cardiovascular event risk in the elderly patients with prediabetes. Methods A total of 100 patients with prediabetes in our hospital from January 2020 to January 2023 were selected as the control group, and 100 patients with prediabetes complicated with cardiovascular events during the same period were selected as the observation group. The serum levels of GABA and IGF-1 in the two groups were detected. Binary Logistic model was used to analyze the influencing factors of cardiovascular events in the elderly patients with prediabetes. The restricted cubic spline method was used to analyze the intensity of association between GABA, IGF-1 and cardiovascular events in the elderly patients with prediabetes. The interaction of GABA and IGF-1 on cardiovascular events in prediabetic patients was analyzed by relative excess risk due to interaction (RERI), attributable proportion to the interaction (AP) and synergy index (S). Results Age, the levels of systolic blood pressure (SBP), fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG), total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol (LDL-C) were significantly higher and the levels of high-density lipoprotein cholesterol (HDL-C), GABA and IGF-1 were lower in the observation group than those in the control group (P<0.05). Binary Logistic regression analysis showed that SBP, FPG and LDL-C were the risk factors, while GABA and IGF-1 were the protective factors for cardiovascular events in the elderly patients with prediabetes (P<0.05).The continuous changes of GABA and IGF-1 were negatively correlated with the strength of association of cardiovascular events, and the risk of cardiovascular events in prediabetic patients was lowest when the level of GABA was > 5.00 μmol/L and the level of IGF-1 was >119 ng/mL. Both high expression of GABA and IGF-1 were as common reference, and after adjusting age, SBP, FPG, TC, TG, LDL-C and HDL-C, low expression of GABA and IGF-1 had a positive interaction on the occurrence of cardiovascular events in prediabetic patients. The synergistic effect was 2.760 times of the summation of the effects of GABA and IGF-1 alone (S=2.760). In the total risk of cardiovascular events in prediabetic individuals, the interaction of low expression of GABA and IGF-1 accounted for 60.43% (API=60.43%). Conclusions GABA and IGF-1 are independent protective factors of cardiovascular events in the patients with prediabetes, and they play a synergistic role in the occurrence of cardiovascular events in the elderly patients with prediabetes. When the expression of GABA and IGF-1 is reduced, the risk of cardiovascular events should be considered.

Key words: aged, prediabetes, gamma-aminobutyric acid, insulin-like growth factor-1, cardiovascular event