Department of Cardiology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Yongzhong Street, Wenzhou, 325000, Zhejiang, China.
Cardiovasc Diabetol. 2023 Nov 22;22(1):320. doi: 10.1186/s12933-023-02054-5.
The Triglyceride-glucose (TyG) index, a novel indicator of insulin resistance, has been associated with mortality from coronary artery diseases, ischemic stroke, and heart failure. In recent years, much emphasis has been placed on the relationship between the TyG index and mortality in the general population. However, the impact of age on the association between TyG and all-cause and cardiovascular mortality remains controversial. This study investigated the link between the TyG index and all-cause and cardiovascular mortality, emphasizing differences between older and non-older populations.
Data from the National Health and Nutrition Examination Survey (2009-2018), encompassing 20,194 participants, were analyzed. The baseline TyG index was calculated as Ln [fasting triglycerides (mg/dL) × fasting glucose (mg/dL)/2]. Multivariate Cox proportional hazards regression models with restricted cubic splines and trend tests were employed to explore the association between the TyG index and all-cause and cardiovascular mortality, with emphasis on age-specific analysis. Subgroup analysis was conducted to examine whether the TyG index's association with mortality varied across different subgroups. Additionally, receiver operating characteristic curves were used to compare the predictive ability of the TyG index with the homeostasis model assessment of insulin resistance (HOMA-IR) for all-cause and cardiovascular mortality.
Over a median follow-up period of 105 months, all-cause mortality accounted for 13.345% of cases, and cardiovascular mortality accounted for 3.387%. Kaplan-Meier curves showed a significant increase in all-cause and cardiovascular mortality with higher TyG index values (both P for log-rank test < 0.001). However, during Cox proportional hazards regression analysis, no linear trend was observed between the TyG index and all-cause or cardiovascular mortality after adjusting for confounding factors (all-cause mortality: P for trend = 0.424; cardiovascular mortality: P for trend = 0.481). Restricted cubic splines revealed a non-linear association between the baseline TyG index and all-cause and cardiovascular mortality in the overall population (all-cause mortality: Non-linear P = 0.003; cardiovascular mortality: Non-linear P = 0.034). The effect of the TyG index was consistent across most subgroups in terms of all-cause and cardiovascular mortality, with no significant interaction with randomized factors (all-cause mortality: P for interaction = 0.077-0.940, cardiovascular mortality: P for interaction = 0.173-0.987), except for the age subgroup (all-cause mortality: P for interaction < 0.001, cardiovascular mortality: P for interaction < 0.001). Further age-specific analysis revealed that the association between the TyG index and all-cause and cardiovascular mortality remained significant in patients aged < 65 but not in those aged ≥ 65. Interestingly, a non-linear association was observed between the TyG index and all-cause mortality in individuals aged < 65 (Non-linear P = 0.011), while a linear relationship was observed with cardiovascular mortality, showing an upward trend (Non-linear P = 0.742, P for trend = 0.010). Further stratification according to age yielded similar results only in patients aged 45-64 (all-cause mortality: Non-linear P = 0.001 and cardiovascular mortality: Non-linear P = 0.902, P for trend = 0.015). Compared to HOMA-IR, the TyG index demonstrated superior predictive performance for all-cause and cardiovascular mortality (all-cause mortality: 0.620 vs. 0.524, P < 0.001; cardiovascular mortality: 0.623 vs. 0.537, P < 0.001).
This study established a significant association between the TyG index and all-cause and cardiovascular mortality in the general population, particularly among individuals aged < 65. Notably, a non-linear association with all-cause mortality was observed in those aged < 65, while a linear relationship with cardiovascular mortality was found.
三酰甘油-葡萄糖（TyG）指数是一种新的胰岛素抵抗指标，与冠心病、缺血性卒中和心力衰竭的死亡率有关。近年来，人们非常关注 TyG 指数与普通人群死亡率之间的关系。然而，年龄对 TyG 与全因和心血管死亡率之间关联的影响仍存在争议。本研究调查了 TyG 指数与全因和心血管死亡率之间的联系，并强调了老年和非老年人群之间的差异。
分析了来自全国健康和营养检查调查（2009-2018 年）的数据，共包括 20194 名参与者。基础 TyG 指数通过计算空腹三酰甘油（mg/dL）与空腹血糖（mg/dL）的乘积再除以 2 得出。采用多变量 Cox 比例风险回归模型和限制性立方样条及趋势检验来探讨 TyG 指数与全因和心血管死亡率之间的关系，并强调年龄特异性分析。进行亚组分析以检查 TyG 指数与死亡率的相关性是否因不同亚组而异。此外，还使用接收者操作特征曲线比较了 TyG 指数与稳态模型评估的胰岛素抵抗（HOMA-IR）对全因和心血管死亡率的预测能力。
在中位随访 105 个月期间，全因死亡率占 13.345%，心血管死亡率占 3.387%。Kaplan-Meier 曲线显示，随着 TyG 指数值的升高，全因和心血管死亡率显著增加（log-rank 检验 P 值均<0.001）。然而，在 Cox 比例风险回归分析中，调整混杂因素后，TyG 指数与全因或心血管死亡率之间未观察到线性趋势（全因死亡率：趋势检验 P 值=0.424；心血管死亡率：趋势检验 P 值=0.481）。限制性立方样条显示，TyG 指数与全因和心血管死亡率之间存在非线性关系（全因死亡率：非线性 P=0.003；心血管死亡率：非线性 P=0.034）。在全人群中，TyG 指数与全因和心血管死亡率的相关性在大多数亚组中是一致的，与随机因素之间没有显著的交互作用（全因死亡率：交互作用 P 值为 0.077-0.940；心血管死亡率：交互作用 P 值为 0.173-0.987），除了年龄亚组（全因死亡率：交互作用 P<0.001；心血管死亡率：交互作用 P<0.001）。进一步的年龄特异性分析显示，TyG 指数与全因和心血管死亡率的相关性在年龄<65 岁的患者中仍然显著，但在年龄≥65 岁的患者中则不显著。有趣的是，在年龄<65 岁的个体中，TyG 指数与全因死亡率之间存在非线性关系（非线性 P=0.011），而与心血管死亡率呈线性关系，呈上升趋势（非线性 P=0.742，趋势检验 P 值=0.010）。根据年龄进一步分层仅在 45-64 岁的患者中得到了类似的结果（全因死亡率：非线性 P=0.001，心血管死亡率：非线性 P=0.902，趋势检验 P 值=0.015）。与 HOMA-IR 相比，TyG 指数对全因和心血管死亡率具有更好的预测性能（全因死亡率：0.620 比 0.524，P<0.001；心血管死亡率：0.623 比 0.537，P<0.001）。
本研究在普通人群中建立了 TyG 指数与全因和心血管死亡率之间的显著关联，特别是在年龄<65 岁的人群中。值得注意的是，在年龄<65 岁的人群中，TyG 指数与全因死亡率之间存在非线性关系，而与心血管死亡率之间存在线性关系。
