Risk factors: HDL-cholesterol levels and mortality in patients with ESRD

The Association between Baseline Serum Lipids and Mortality in Peritoneal Dialysis Patients

INTRODUCTION

Lipid disturbances are common in ESRD patients. In peritoneal dialysis (PD) patients, dyslipidemia is even more common. This study aimed to examine whether serum lipids were associated with prognosis of PD patients.

METHODS

Patients from a multicenter retrospective cohort were used for the present study. The primary endpoint was all-cause mortality. Cox regression was used to analyze the association between serum lipids including total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein, and triglycerides and the prognosis.

RESULTS

The results showed that lower total cholesterol and LDL levels at the initiation of PD predicted higher all-cause mortality in PD patients. Multivariate analysis reveal that the association disappeared after adjusting for age, gender, albumin, prealbumin, protein catabolic rate normalized to body weight, C-reactive protein, and residual renal function. Further analysis showed that patients with lower total cholesterol/LDL had a higher mortality only during the first 24 months of follow-up. In the patients who survived >2 years after PD, lower total cholesterol/LDL was not associated with higher long-term all-cause mortality any more.

CONCLUSION

Lower total cholesterol/LDL levels at the initiation of PD were associated with overall mortality in PD patients. The association could be potentially modified by malnutrition, inflammation, and residual renal function or disappeared after 24 months.

Monocyte to high-density lipoprotein ratio and cardiovascular events in patients on peritoneal dialysis

BACKGROUND AND AIMS

The monocyte to high-density lipoprotein cholesterol ratio (MHR) is associated with multiple cardiovascular diseases. However, the role of the MHR in predicting cardiovascular diseases in patients on peritoneal dialysis remains unclear.

METHODS AND RESULTS

Eight hundred and eighty incident peritoneal dialysis patients were enrolled from November 1, 2005, to February 28, 2017, and followed until May 31, 2017. Primary outcomes were cardiovascular events. Using the X-tile program, these patients were divided into three groups according to the MHR. Kaplan-Meier method and Cox regressions were used for survival analysis. During a median follow-up period of 26 months (interquartile range: 12-39 months), 139 cardiovascular events were recorded. After multiple adjustment, the high MHR group was associated with a 1.97-fold increase in the cardiovascular events hazard compared to that of the low group in the overall population (hazard ratio: 1.97; 95% CI, 1.19-3.28; P = 0.009). Subgroup analysis demonstrated that the association between the MHR and a higher risk of cardiovascular events was strongest in the subgroup of patients with diabetes (P for interaction = 0.004). In this subgroup, the high MHR group was found to be associated with a higher risk of cardiovascular events compared to the low group (hazard ratio: 7.69; 95% CI, 2.76-21.47).

CONCLUSION

This study suggests that the MHR is independently associated with the risk of cardiovascular events in patients undergoing peritoneal dialysis, and diabetes status can influence the association between the MHR and the risk of cardiovascular events.

Patients with Rheumatoid Arthritis Show Altered Lipoprotein Profiles with Dysfunctional High-Density Lipoproteins that Can Exacerbate Inflammatory and Atherogenic Process

Objective

In order to identify putative biomarkers in lipoprotein, we compared lipid and lipoprotein properties between rheumatoid arthritis (RA) patients and control with similar age.

Methods

We analyzed four classes of lipoproteins (VLDL, LDL, HDL₂, HDL₃) from both male (n = 8, 69±4 year-old) and female (n = 25, 53±7 year-old) rheumatoid arthritis (RA) patients as well as controls with similar age (n = 13).

Results

Although RA group showed normal levels of total cholesterol (TC), low-density lipoprotein (LDL)-cholesterol, and glucose, however, the RA group showed significantly reduced high-density lipoprotein (HDL)-C level and ratio of HDL-C/TC. The RA group showed significantly elevated levels of blood triglyceride (TG), uric acid, and cholesteryl ester transfer protein (CETP) activity. The RA group also showed elevated levels of advanced glycated end (AGE) products in all lipoproteins and severe aggregation of apoA-I in HDL. As CETP activity and TG contents were 2-fold increased in HDL from RA group, paraoxonase activity was reduced upto 20%. Electron microscopy revealed that RA group showed much less HDL₂ particle number than control. LDL from the RA group was severely oxidized and glycated with greater fragmentation of apo-B, especially in female group, it was more atherogenic via phagocytosis.

Conclusion

Lipoproteins from the RA patients showed severely altered structure with impaired functionality, which is very similar to that observed in coronary heart patients. These dysfunctional properties in lipoproteins from the RA patients might be associated with high incidence of cardiovascular events in RA patients.

HDL Cholesterol Efflux Does Not Predict Cardiovascular Risk in Hemodialysis Patients

The cardioprotective effect of HDL is thought to be largely determined by its cholesterol efflux capacity, which was shown to inversely correlate with atherosclerotic cardiovascular disease in populations with normal kidney function. Patients with ESRD suffer an exceptionally high cardiovascular risk not fully explained by traditional risk factors. Here, in a post hoc analysis in 1147 patients with type 2 diabetes mellitus on hemodialysis who participated in the German Diabetes Dialysis Study (4D Study), we investigated whether the HDL cholesterol efflux capacity is predictive for cardiovascular risk. Efflux capacity was quantified by incubating human macrophage foam cells with apoB-depleted serum. During a median follow-up of 4.1 years, 423 patients reached the combined primary end point (composite of cardiac death, nonfatal myocardial infarction, and stroke), 410 patients experienced cardiac events, and 561 patients died. Notably, in Cox regression analyses, we found no association of efflux capacity with the combined primary end point (hazard ratio [HR], 0.96; 95% confidence interval [95% CI], 0.88 to 1.06; P=0.42), cardiac events (HR, 0.92; 95% CI, 0.83 to 1.02; P=0.11), or all-cause mortality (HR, 0.96; 95% CI, 0.88 to 1.05; P=0.39). In conclusion, HDL cholesterol efflux capacity is not a prognostic cardiovascular risk marker in this cohort of patients with diabetes on hemodialysis.

HDL abnormalities in nephrotic syndrome and chronic kidney disease

Normal HDL activity confers cardiovascular and overall protection by mediating reverse cholesterol transport and through its potent anti-inflammatory, antioxidant, and antithrombotic functions. Serum lipid profile, as well as various aspects of HDL metabolism, structure, and function can be profoundly altered in patients with nephrotic range proteinuria or chronic kidney disease (CKD). These abnormalities can, in turn, contribute to the progression of cardiovascular complications and various other comorbidities, such as foam cell formation, atherosclerosis, and/or glomerulosclerosis, in affected patients. The presence and severity of proteinuria and renal insufficiency, as well as dietary and drug regimens, pre-existing genetic disorders of lipid metabolism, and renal replacement therapies (including haemodialysis, peritoneal dialysis, and renal transplantation) determine the natural history of lipid disorders in patients with kidney disease. Despite the adverse effects associated with dysregulated reverse cholesterol transport and advances in our understanding of the underlying mechanisms, safe and effective therapeutic interventions are currently lacking. This Review provides an overview of HDL metabolism under normal conditions, and discusses the features, mechanisms, and consequences of HDL abnormalities in patients with nephrotic syndrome or advanced CKD.