Triglyceride-Rich Lipoproteins, Apolipoproteins, and Atherosclerotic Cardiovascular Events Among Patients with Diabetes Mellitus and End-Stage Renal Disease on Hemodialysis

Proprotein convertase subtilisin/kexin type 9 (PCSK9) and clinical outcomes in dialysis patients

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9), a factor accelerating the degradation of LDL receptors, was associated with a gender-dependent risk for cardiovascular (CV) events in the general population and with all-cause and CV mortality in two relatively small studies in black Africans and South Korean haemodialysis patients. The effect modification by gender was untested in these studies.

METHODS

The study enrolled 1188 dialysis patients from the Prospective Registry of The Working Group of Epidemiology of Dialysis Region Calabria (PROGREDIRE) cohort. PCSK9 was measured by colorimetric enzyme-linked immunosorbent assay. The primary outcomes were all-cause and CV mortality. Statistical analysis included Cox regression analysis and effect modification analysis.

RESULTS

During a median 2.9-year follow-up, out of 494 deaths, 278 were CV-related. In unadjusted analyses, PCSK9 levels correlated with increased all-cause (HRfor1ln unit increase: 1.23, 95% CI 1.06-1.43, p =.008) and CV mortality (HRfor1ln unit increase: 1.26, 95% CI 1.03-1.54, p =.03). After multivariate adjustment, these associations were no longer significant (all-cause mortality, HRfor 1 ln unit increase: 1.16, 95% CI .99-1.36, p =.07; CV mortality, HRfor1ln unit increase: 1.18, 95% CI .95-1.46, p =.14). However, in fully adjusted interaction analyses, a doubling in the risk of this outcome in women was registered (Women, HRfor1ln unit increase: 1.88, 95% CI 1.27-2.78, p =.002; Men, HRfor1ln unit increase: 1.07, 95% CI .83-1.38, p =.61; p for effect modification: .02).

CONCLUSIONS

PCSK9 levels are unrelated to all-cause mortality in haemodialysis patients but, like in studies of the general population, independently of other risk factors, entail a doubling in the risk of CV events in women in this population.

Association between the triglyceride to high-density lipoprotein cholesterol ratio and mortality in Chinese maintenance haemodialysis patients: a retrospective cohort study

OBJECTIVE

To investigate the relationship between the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and all-cause and cardiovascular (CV) mortality in Chinese haemodialysis (HD) patients.

DESIGN

Retrospective cohort study.

SETTING

Patients from June 2015 to September 2016 and followed through September 2021 were categorised into quartiles according to the follow-up averaged TG/HDL-C ratio. The association between TG/HDL-C and mortality was examined by univariate and multivariate time-varying Cox regression analyses. The C-index was used to assess the predictive accuracy of the Cox regression models.

PARTICIPANTS

A total of 534 maintenance HD patients were enrolled.

PRIMARY AND SECONDARY OUTCOME MEASURES

The outcomes were all-cause death and CV mortality.

RESULTS

During the median follow-up of 61 months, 207 patients died, with 94 (45.4%) classified as CV death. After adjusting for confounders, multivariate time-varying Cox regression analysis showed that the quartile 4 group (TG/HDL-C ≥2.64) was associated with decreased all-cause mortality (adjusted HR 0.51, 95% CI 0.33-0.77, p=0.001) and CV mortality (adjusted HR 0.31; 95% CI 0.16 to 0.62; p=0.001) in maintenance HD patients. Model 1 of all-cause mortality achieved a C-index of 0.72 (95% CI 0.68 to 0.75), and model 2 achieved a C-index of 0.77 (95% CI 0.73 to 0.82). The C-index for model 1 in CV mortality was 0.74 (95% CI 0.70 to 0.77), and the C-index for model 2 was 0.80 (95% CI 0.75 to 0.84).

CONCLUSIONS

High TG/HDL-C was associated with decreased all-cause and CV mortality in HD patients.

Non-fasting lipids and cardiovascular disease in those with and without diabetes in Alberta's Tomorrow Project: A prospective cohort study

AIMS

Non-fasting remnant cholesterol (RC) is a novel marker of cardiovascular disease (CVD) risk, however, data on this relationship in Canadians with diabetes (at high risk of CVD) is lacking. The objective of this analysis was to determine the relationship of RC with CVD in individuals with and without diabetes in the Alberta's Tomorrow Project (ATP) cohort.

METHODS

Non-fasting lipid data collected as part of the ATP was linked to administrative health records (October 2000-March 2015) to ascertain incident CVD and prevalent diabetes. Participants without prevalent CVD or incident diabetes and who had complete, non-negative non-fasting lipid data collected with triglycerides <4.5 mmol/L were included (n = 13,631). The relationship between non-fasting RC and incident CVD diagnoses was assessed by Cox proportional hazards regression, after stratification by diabetes status.

RESULTS

Participants were 69.8% women with a mean age of 61.6 ± 9.7 years, and 6.5% had prevalent diabetes. Non-fasting RC was higher in participants with diabetes compared to those without (mean 0.94 ± 0.41 mmol/L vs. 0.77 ± 0.38 mmol/L, p < 0.0001) and was associated with increased risk of incident CVD among those without diabetes (adjusted hazard ratio (aHR) 1.22, 95% CI 1.03-1.43, p = 0.02). Although a similar trend was observed in participants with diabetes it did not reach statistical significance (aHR 1.31, 95% CI 0.84-2.05, p = 0.23).

CONCLUSIONS

Elevated non-fasting RC predicted increased CVD risk in middle and older-aged adults without diabetes; similar trends were observed in participants with diabetes and require further testing in a larger sample.

Nonfasting remnant cholesterol and cardiovascular disease risk prediction in Albertans: a prospective cohort study

BACKGROUND

European studies have shown that nonfasting remnant cholesterol can be a strong predictor of cardiovascular disease risk and may contribute to identifying residual risk; however, Canadian data are lacking on nonfasting remnant cholesterol. In this study, we aimed to determine the relation between nonfasting remnant cholesterol, low-density lipoprotein (LDL) cholesterol and cardiovascular disease among people in Alberta.

METHODS

In this retrospective analysis, we used data from Alberta's Tomorrow Project, a large prospective cohort that enrolled Albertans aged 35-69 years (2000-2015). Participants with consent to data linkage, with complete nonfasting lipid data and without existing cardiovascular disease were included. The nonfasting remnant cholesterol and LDL cholesterol relation with a composite cardiovascular disease outcome of major incident cardiovascular diagnoses, ascertained by linking to Alberta Health databases, was determined by multivariable logistic regression, adjusting for age, sex, statin use, comorbidities, and LDL cholesterol or remnant cholesterol.

RESULTS

The final sample of 13 988 participants was 69.4% female, and the mean age was 61.8 (standard deviation [SD] 9.7) years. Follow-up time was approximately 15 years. Mean remnant cholesterol was significantly higher among individuals with versus without cardiovascular disease (0.87 [SD 0.40] mmol/L v. 0.78 [SD 0.38] mmol/L, standardized mean difference [SMD] -0.24), and mean LDL cholesterol was significantly lower (2.69 [SD 0.93] mmol/L v. 2.88 [SD 0.84] mmol/L, SMD 0.21). The odds of incident composite cardiovascular disease were significantly increased per mmol/L increase in remnant cholesterol (adjusted odds ratio [OR] 1.48, 95% confidence interval [CI] 1.27-1.73) but significantly decreased per mmol/L increase in LDL cholesterol (adjusted OR 0.73, 95% CI 0.68-0.79).

INTERPRETATION

In this large Albertan cohort of predominantly older females, nonfasting remnant cholesterol had a positive relation with cardiovascular disease incidence, whereas LDL cholesterol did not. These findings support the clinical utility of measuring non-fasting remnant cholesterol to detect cardiovascular disease risk.

Vitamin E (Alpha-Tocopherol) Metabolism and Nutrition in Chronic Kidney Disease

Vitamin E (alpha-tocopherol) is an essential micronutrient and fat-soluble antioxidant with proposed role in protecting tissues from uncontrolled lipid peroxidation. This vitamin has also important protein function and gene modulation effects. The metabolism of vitamin E depends on hepatic binding proteins that selectively retain food alpha-tocopherol for incorporation into nascent VLDL and tissue distribution together with esterified cholesterol and triglycerides. Chronic kidney disease (CKD) is a condition of oxidative stress and increased lipid peroxidation, that are associated with alterations of alpha-tocopherol metabolism and function. Specific changes have been reported for the levels of its enzymatic metabolites, including both short-chain and long-chain metabolites, the latter being endowed with regulatory functions on enzymatic and gene expression processes important for the metabolism of lipids and xenobiotics detoxification, as well as for the control of immune and inflammatory processes. Vitamin E therapy has been investigated in CKD using both oral vitamin E protocols and vitamin E-coated hemodialyzers, showing promising results in the secondary prevention of cardiovascular disease, as well as of immune and hematological complications. These therapeutic approaches are reviewed in the present article, together with a narrative excursus on the main findings indicating CKD as a condition of relative deficiency and impaired metabolism of vitamin E.