Low-density lipoprotein cholesterol treatment and outcomes in patients with type 2 diabetes and established cardiovascular disease: Insights from TECOS

Fasting triglycerides are positively associated with cardiovascular mortality risk in people with diabetes

AIMS

We investigated the association of fasting triglycerides with cardiovascular disease (CVD) mortality.

METHODS AND RESULTS

This cohort study included US adults from the National Health and Nutrition Examination Surveys from 1988 to 2014. CVD mortality outcomes were ascertained by linkage to the National Death Index records. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of triglycerides for CVD mortality. The cohort included 26,570 adult participants, among which 3,978 had diabetes. People with higher triglycerides had a higher prevalence of diabetes at baseline. The cohort was followed up for a mean of 12.0 years with 1,492 CVD deaths recorded. A 1-natural-log-unit higher triglyceride was associated with a 30% higher multivariate-adjusted risk of CVD mortality in participants with diabetes (HR, 1.30; 95% CI, 1.08-1.56) but not in those without diabetes (HR, 0.95; 95% CI, 0.83-1.07). In participants with diabetes, people with high triglycerides (200-499 mg/dL) had a 44% (HR, 1.44; 95% CI, 1.12-1.85) higher multivariate-adjusted risk of CVD mortality compared with those with normal triglycerides (<150 mg/dL). The findings remained significant when diabetes was defined by fasting glucose levels alone, or after further adjustment for the use of lipid-lowering medications, or after the exclusion of those who took lipid-lowering medications.

CONCLUSIONS

This study demonstrates that fasting triglycerides of ≥200 mg/dl are associated with an increased risk of CVD mortality in patients with diabetes but not in those without diabetes. Future clinical trials of new treatments to lower triglycerides should focus on patients with diabetes.

Roles of Cardiometabolic Factors in Mediating the Causal Effect of Type 2 Diabetes on Cardiovascular Diseases: A Two-Step, Two-Sample Multivariable Mendelian Randomization Study

Objective

The objective of this study is to investigate the roles of cardiometabolic factors (including blood pressure, blood lipids, thyroid function, body mass, and insulin sensitivity) in mediating the causal effect of type 2 diabetes (T2DM) on cardiovascular disease (CVD) outcomes.

Design

Two-step, two-sample multivariable Mendelian randomization (MVMR) study.

Setting

International genome-wide association study (GWAS) consortia data.

Exposure

Type 2 diabetes, blood pressure: systolic blood pressure (SBP), diastolic blood pressure (DBP); blood lipids: low-density lipoprotein (LDL), high-density lipoprotein (HDL), total cholesterol (TC), triglycerides (TG); thyroid function: hyperthyroidism, hypothyroidism; body mass index (BMI), waist-hip-ratio (WHR), and insulin sensitivity.

Main Outcomes

Cardiovascular disease includes coronary heart disease (CHD), myocardial infarction (MI), and stroke.

Methods

Summary-level data for exposures and main outcomes were extracted from GWAS consortia. We used two-sample MR to illustrate the causal effect of T2DM on CVD subtypes and regression-based MVMR to quantify the possible mediation effects of cardiometabolic factors on CVD.

Results

Each additional unit of log odds of T2DM increased 16% risk of CHD [odds ratio (OR): 1.16, 95% CI: 1.12–1.21], 15% risk of myocardial infarction (MI) (OR: 1.15, 95% CI: 1.10–1.20), and 10% risk of stroke (OR: 1.10, 95% CI: 1.06–1.13). In mediation analysis, SBP, DBP, and TG were found as main mediators, while the mediation effects of other cardiometabolic factors were not significant. The proportion of total effect of T2DM on CHD mediated by SBP, DBP, and TG was 16% (95% CI: 8–24%), 7% (95% CI: 1–13%) and 10% (95% CI: 2–18%), respectively. Mediation effect of SBP and DBP on MI and stroke, TG on MI was also prominent, while mediation effect of TG on stroke was not significant. The combined mediation effect of all the three mediators accounted for 29%, 26%, and 13% of the total effect of T2DM on CHD, MI, and stroke, respectively.

Conclusion

Systolic blood pressure, DBP, and TG mediate a substantial proportion of the causal effect of T2DM on CVD and thus interventions on these factors might reduce the considerable excess risk of CVD among patients with T2DM.

Low-Density Lipoprotein Cholesterol and Mortality Risk in Elderly Patients Undergoing Valve Replacement Surgery: A Propensity Score Matching Analysis

BACKGROUND

The prognostic value of low-density lipoprotein cholesterol (LDL-C) in elderly patients is controversial. This study aimed to elucidate the relationship between the preoperative LDL-C and adverse outcomes in elderly patients undergoing valve replacement surgery (VRS).

METHODS

A total of 2,552 aged patients (age ≥ 60 years) undergoing VRS were retrospectively recruited and divided into two groups according to LDL-C level on admission: low LDL-C (<70 mg/dL, n = 205) and high LDL-C groups (≥ 70 mg/dL, n = 2,347). The association between the preoperative LDL-C with in-hospital and one-year mortality was evaluated by propensity score matching analysis and multivariate analysis.

RESULTS

The mean age was 65 ± 4 years and 1,263 (49.5%) were men. Patients in the low LDL-C group were significantly older (65.9 ± 4.6 vs. 64.9 ± 4.1, p = 0.002), with more male (65.4 vs. 48.1%, p < 0.001), higher alanine transaminase (ALT) (21 vs. 19, p = 0.001), lower serum albumin (35.3 ± 4.6 vs. 37.1 ± 4.1, p < 0.001), higher serum creatinine (92.2 ± 38.2 vs.84.6 ± 26.1, p = 0.006), lower lymphocyte count (1.7 ± 0.7 vs. 1.9 ± 0.6, p < 0.001), lower hemoglobin (121.9 ± 22.3 vs. 130.2 ± 16.5, p < 0.001), lower platelet count (171.3 ± 64.3 vs. 187.7 ± 58.7, p < 0.001), lower prognostic nutrition index (44 ± 6.2 vs. 46.7 ± 5.8, p < 0.001), and more severe tricuspid regurgitation (33.7 vs. 25.1%, p = 0.008). The rates of in-hospital death (11.2 vs. 3.7%, p < 0.001) and major adverse clinical events (17.6 vs. 9.6%, p < 0.001) were significantly higher in the low LDL-C group. The cumulative one-year death rate was significantly higher in the low LDL-C group (Log-Rank = 16.6, p < 0.001). After matching analysis and multivariate analysis, no association between LDL-C level and adverse outcomes was detected (all p > 0.05).

CONCLUSION

Our study did not support the negative relationship between LDL-C level and mortality risk in elderly patients undergoing VRS.