Influence of impaired glucose tolerance alone and combined with metabolic syndrome on long-term risk of cardiovascular events and mortality.

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.

Non-diabetes status after diagnosis of impaired glucose tolerance and risk of long-term death and vascular complications: A post hoc analysis of the Da Qing Diabetes Prevention Outcome Study.

BACKGROUND: The association between years of non-diabetes status after diagnosis of impaired glucose tolerance (IGT) and the risk of long-term death and cardiovascular outcomes needed to be clarified. METHODS AND FINDINGS: In this post hoc analysis, we included 540 individuals with IGT who participated in the original Da Qing Diabetes Prevention Study (DQDPS). In the DQDPS, all participants were diagnosed with IGT by a 75 g oral glucose tolerance test and randomized to intervention or control groups with a 6-year lifestyle intervention trial. After the completion of the trial, death, cardiovascular events, and microvascular complications were monitored over a 30-year follow-up. In this post hoc analysis, the Cox analysis assessed the extended risk of these outcomes in individuals who either remained non-diabetes status or progressed to diabetes at the end of 2, 4, and 6 years after diagnosis of IGT. In all participants, the difference in the cumulative incidence rate of the outcomes between the diabetes and non-diabetes group gradually increased over 30 years. Compared with the diabetes group, a significantly lower risk of all-cause death (hazard ratio [HR]: 0.74; 95% confidence interval [CI]: 0.57 to 0.97, p = 0.026), cardiovascular events (HR: 0.63; 95% CI: 0.49 to 0.82, p < 0.001), and microvascular complications (HR: 0.62; 95% CI: 0.45 to 0.86, p = 0.004) first emerged in individuals who remained non-diabetes at the 4 years visit, whereas the significant risk reduction in cardiovascular death was first observed at the end of 6 years (HR: 0.56; 95% CI: 0.39 to 0.81, p = 0.002) after adjustment for age, sex, smoking status, BMI, systolic blood pressure, blood glucose, total cholesterol, intervention, and medications (including insulin plus oral hypoglycaemics, antihypertensives, and lipid-lowering agents). The results in the original intervention group alone were similar to the whole group. The main limitations of our study are the limited number of participants and the sole ethnicity of the Chinese population. CONCLUSIONS: In this study, we observed that maintaining several years of non-diabetes status after IGT diagnosis was associated with a significant reduction in long-term risk of death and vascular complications, and for most of these outcomes, maintaining at least 4 years of non-diabetes status may be needed to achieve a significant risk reduction.

Efficacy of 1-hour postload plasma glucose as a suitable measurement in predicting type 2 diabetes and diabetes-related complications: A post hoc analysis of the 30-year follow-up of the Da Qing IGT and Diabetes Study.

AIM: To evaluate whether 1-hour plasma glucose (1hPG) can be a comparable measurement to 2-hour plasma glucose (2hPG) in identifying individuals at high risk of developing diabetes. METHODS: A total of 1026 non-diabetic subjects in the Da Qing IGT and Diabetes Study were included and classified according to baseline postload 1hPG. The participants were followed up and assessed at 6-, 20- and 30year follow-up for outcomes including diabetes, all-cause and cardiovascular mortality, cardiovascular disease (CVD) events, and microvascular disease. We then conducted a proportional hazards analysis in this post hoc study to determine the risks of developing type 2 diabetes and its complications in a '1hPG-normal' group (1hPG <8.6 mmol/L) and a '1hPG-high' group (≥8.6 mmol/L). The predictive values of 1hPG and 2hPG were evaluated using a time-dependent receiver-operating characteristic (ROC) curve. RESULTS: Compared with the 1hPG-normal group, the 1hPG-high group had increased risk of diabetes (hazard ratio [HR] 4.45, 95% CI 3.43-5.79), all-cause mortality (HR 1.46, 95% CI 1.07-2.01), CVD mortality (HR 1.84, 95% CI 1.16-2.95), CVD events (HR 1.39, 95% CI 1.03-1.86) and microvascular disease (HR 1.70, 95% CI: 1.03-2.79) after adjusting for confounders. 1hPG exhibited a higher area under the ROC curve (AUC) for predicting diabetes than 2hPG during the long-term follow-up (AUC [1hPG vs. 2hPG]: 10 years: 0.86 vs. 0.84, p = 0.08; 20 years: 0.88 vs. 0.87, p = 0.04; 30 years: 0.85 vs. 0.82, p = 0.009). CONCLUSIONS: Elevated 1hPG level (≥8.6 mmol/L) was associated with increased risk of developing type 2 diabetes and its long-term complications, and could be considered as a suitable measurement for identifying individuals at high risk of type 2 diabetes.

Influence of a diet and/or exercise intervention on long-term mortality and vascular complications in people with impaired glucose tolerance: Da Qing Diabetes Prevention Outcome study.

AIM: We aimed to investigate the long-term influence of a diet and/or exercise intervention on long-term mortality and cardiovascular disease (CVD) events. METHODS: The Da Qing Diabetes Prevention Study had 576 participants with impaired glucose tolerance (IGT) randomized to diet-only, exercise-only and diet-plus-exercise intervention group and control group. The participants underwent lifestyle interventions for 6 years. The subsequent Da Qing Diabetes Prevention Outcome Study was a prospective cohort study to follow-up the participants for up to 24 years after the end of 6-year intervention. In total, 540 participants completed the follow-up, while 36 subjects lost in follow-up. Cox proportional hazards analysis was applied to assess the influence of lifestyle interventions on targeted outcomes. RESULTS: Compared with controls, the diet-only intervention in people with IGT was significantly associated with a reduced risk of all-cause death [hazard ratio (HR) 0.77, 95% confidence interval (CI) (0.61-0.97)], CVD death [HR 0.67, 95% CI (0.46-0.97)] and CVD events [HR 0.72, 95% CI (0.54-0.96)]. The diet-plus-exercise intervention was significantly associated with a decreased risk of all-cause death [HR 0.64, 95% CI (0.48-0.84)], CVD death [HR 0.54, 95% CI (0.30-0.97)] and CVD events [HR 0.68, 95% CI (0.52-0.90)]. Unexpectedly, the exercise-only intervention was not significantly associated with the reduction of any of these outcomes, although there was a consistent trend towards reduction. CONCLUSIONS: A diet-only intervention and a diet-plus-exercise intervention in people with IGT were significantly associated with a reduced risk of all-cause death, CVD death and CVD events, while an exercise-only intervention was not. It suggests that diet-related interventions may have a potentially more reliable influence on long-term vascular complications and mortality.

Circulating palmitoyl sphingomyelin levels predict the 10-year increased risk of cardiovascular disease death in Chinese adults: findings from the Da Qing Diabetes Study.

BACKGROUND: Higher levels of palmitoyl sphingomyelin (PSM, synonymous with sphingomyelin 16:0) are associated with an increased risk of cardiovascular disease (CVD) in people with diabetes. Whether circulating PSM levels can practically predict the long-term risk of CVD and all-cause death remains unclear. This study aimed to investigate whether circulating PSM is a real predictor of CVD death in Chinese adults with or without diabetes. METHODS: A total of 286 and 219 individuals with and without diabetes, respectively, from the original Da Qing Diabetes Study were enrolled. Blood samples collected in 2009 were used as a baseline to assess circulating PSM levels. The outcomes of CVD and all-cause death were followed up from 2009 to 2020, and 178 participants died, including 87 deaths due to CVD. Cox proportional hazards regression was used to estimate HRs and their 95% CIs for the outcomes. RESULTS: Fractional polynomial regression analysis showed a linear association between baseline circulating PSM concentration (log-2 transformed) and the risk of all-cause and CVD death (p < 0.001), but not non-CVD death (p > 0.05), in all participants after adjustment for confounders. When the participants were stratified by PSM-tertile, the highest tertile, regardless of diabetes, had a higher incidence of CVD death (41.5 vs. 14.7 and 22.2 vs. 2.9 per 1000 person-years in patients with and without diabetes, respectively, all log-rank p < 0.01). Individuals with diabetes in the highest tertile group had a higher risk of CVD death than those in the lowest tertile (HR = 2.73; 95%CI, 1.20-6.22). CONCLUSIONS: Elevated PSM levels are significantly associated with a higher 10-year risk of CVD death, but not non-CVD death, in Chinese adults with diabetes. These findings suggest that PSM is a potentially useful long-term predictor of CVD death in individuals with diabetes.