Abstract
BACKGROUND: This study aimed to investigate the potential differences in the influence of impaired glucose tolerance (IGT) with and without metabolic syndrome (MetS) on cardiovascular (CV) events and mortality. METHODS: Participants having IGT with MetS (IGT_MetS), those having IGT without MetS (IGT_non_MetS), and those having normal glucose tolerance (NGT) without MetS (NGT_non_MetS) (N = 246, N = 294, and N = 471, respectively) were included in this study. Cox proportional hazards regression was used to examine the relationship among these three groups and CV events and mortality. RESULTS: Over the 30-year follow-up period, 57 (12.1%) participants having NGT_non_MetS, 55 (18.71%) with IGT_non_MetS, and 74 (30.08%) with IGT_MetS experienced CV mortality. After adjusting for risk factors, the hazard ratios for CV mortality were 2 (95% confidence interval [CI], 1.38-2.91) for the IGT_non_MetS group and 2.96 (95% CI, 2.09-4.19) for the IGT_MetS group, compared with the NGT_non_MetS group. Similar patterns were observed for CV events, with hazard ratios of 1.49 (95% CI, 1.19-1.88) for the IGT_non_MetS group and 1.97 (95% CI, 1.58-2.47) for the IGT_MetS group. Sensitivity analysis revealed that the hazard ratios of the IGT_non_MetS and IGT_MetS groups indicated a higher risk of all-cause mortality, myocardial infarction events or myocardial infarction mortality, and stroke events or stroke mortality compared with that of the NGT_non_MetS group. CONCLUSION: IGT_non_MetS increased the risk of CV mortality and events. Furthermore, when it occurred in conjunction with MetS, it further increased the risk of CV mortality and events. This suggested that active intervention is required.