Non-HDL cholesterol and apolipoprotein B in the dyslipidemic classification of type 2 diabetic patients

Increasing the complexity of lipoprotein characterization for cardiovascular risk in type 2 diabetes

The burden of cardiovascular disease is particularly high among individuals with diabetes, even when LDL cholesterol is normal or within the therapeutic target. Despite this, cholesterol accumulates in their arteries, in part, due to persistent atherogenic dyslipidaemia characterized by elevated triglycerides, remnant cholesterol, smaller LDL particles and reduced HDL cholesterol. The causal link between dyslipidaemia and atherosclerosis in T2DM is complex, and our contention is that a deeper understanding of lipoprotein composition and functionality, the vehicle that delivers cholesterol to the artery, will provide insight for improving our understanding of the hidden cardiovascular risk of diabetes. This narrative review covers three levels of complexity in lipoprotein characterization: 1-the information provided by routine clinical biochemistry, 2-advanced nuclear magnetic resonance (NMR)-based lipoprotein profiling and 3-the identification of minor components or physical properties of lipoproteins that can help explain arterial accumulation in individuals with normal LDLc levels, which is typically the case in individuals with T2DM. This document highlights the importance of incorporating these three layers of lipoprotein-related information into population-based studies on ASCVD in T2DM. Such an attempt should inevitably run in parallel with biotechnological solutions that allow large-scale determination of these sets of methodologically diverse parameters.

Hypertriglyceridemia, a causal risk factor for atherosclerosis, and its laboratory assessment

Epidemiological and clinical studies show a causal association between serum triglyceride (TG) level, the number of triglyceride-rich lipoproteins (TRLs) and their remnants, and the increased risk of atherosclerosis and cardiovascular disease (CVD) development. In light of current guidelines for dyslipidemia management, the laboratory parameters reflecting TRL content are recommended as part of the routine lipid analysis process and used for CVD risk assessment, especially in people with hypertriglyceridemia (HTG), diabetes mellitus, obesity and low levels of low-density lipoprotein cholesterol (LDL-C), in which high residual CVD risk is observed. The basic routinely available laboratory parameters related with TRL are serum TG and non-high-density lipoprotein cholesterol (non-HDL-C) levels, but there are also other biomarkers related to TRL metabolism, the determination of which can be helpful in identifying the basis of HTG development or assessing CVD risk or can be the target of pharmacological intervention. In this review, we present the currently available laboratory parameters related to HTG. We summarise their link with TRL metabolism and HTG development, the determination methods as well as their clinical significance, the target values and interpretation of the results in relation to the current dyslipidemia guidelines.

Low-density lipoprotein cholesterol-to-apolipoprotein B ratio as a potential indicator of LDL particle size and plasma atherogenicity in type 2 diabetes

AIMS

Atherogenic dyslipidemia, associated with small, dense low-density lipoprotein-cholesterol (S-LDL) particles and impaired metabolism of triglycerides (TGs) and high-density lipoprotein-cholesterol (HDL-c), leads to the development of atherosclerosis-related complications of type 2 diabetes mellitus. Based on the hypothesis that an LDL-c-to-apolipoprotein B ratio (LDL/ApoB) < 1.2 may predict the prevalence of S-LDL, this study aimed to evaluate the LDL/ApoB ratio in patients with type 2 diabetes with moderately elevated TG levels.

METHODS

The study population consisted of 121 outpatients with type 2 diabetes (S-LDL group, LDL/ApoB < 1.2, n = 79; L-LDL group, LDL/ApoB > 1.2, n = 42) and 58 healthy subjects. The LDL/ApoB ratio was calculated from the measured LDL-c and ApoB levels in participants with TG levels lower than 4.5 mmol/L. Since TGs and HDL-c are included in the atherogenic index of plasma (AIP), we evaluated the relationship between LDL/ApoB and the AIP.

RESULTS

Higher levels of AIP, TG (both P < 0.0001), and lipid hydroperoxides (LOOH) (P < 0.001) and lower levels of HDL-c, total cholesterol, and non-HDL-c (P < 0.001, <0.01, <0.05, respectively) were found in the S-LDL group compared to the L-LDL group. There were significant relationships between the LDL/ApoB ratio and the AIP, TG (both P < 0.0001), LOOH (P < 0.0005), and HDL-c levels (P < 0.05) in the S-LDL group.

CONCLUSIONS

The prevalence of S-LDL particles (65%) and the close association of LDL/ApoB with the AIP suggest that this ratio may be a potential indicator of increased cardiovascular risk in patients with type 2 diabetes.

Apolipoprotein B and non-high-density lipoprotein cholesterol reveal a high atherogenicity in individuals with type 2 diabetes and controlled low-density lipoprotein-cholesterol

Background

Lipid-lowering therapy is guided by Low-density-lipoprotein cholesterol (LDL-c) levels, although the cardiovascular disease (CVD) risk could be better reflected by other lipid parameters. This study aimed at comparing a comprehensive lipid profile between patients with type 2 diabetes mellitus (T2DM) with LDL-c concentration within and above target.

Methods

A comprehensive lipid profile was characterized in 96 T2DM patients. The European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) 2016 and 2019 Guidelines for the Management of Dyslipidemias were used to define LDL-c targets.

Results

In this population, only 28.1 and 16.7% of patients had mean LDL-c levels within target, as defined by the 2016 and 2019 guidelines, respectively. Applying the 2016 guidelines criteria, in patients with LDL-c within target, 22, 25 and 44% presented non-high-density lipoprotein cholesterol (non-HDL-c), Apolipoprotein B (ApoB) and oxidized LDL-c levels above the recommended range, respectively, whereas according to the 2019 guidelines criteria, 50, 39 and 44% of the patients with LDL-c within target had elevated high-density lipoprotein cholesterol (HDL-c), ApoB and oxidized LDL-c levels, respectively. LDL-c was strongly correlated with non-HDL-c (r = 0.850), ApoB (r = 0.656) and oxidized LDL-c (r = 0.508). Similarly, there was a strong correlation between non-HDL-c with both ApoB (r = 0.808) and oxidized LDL-c (r = 0.588).

Conclusions

These findings emphasize the limitations of only considering LDL-c concentration for cardiovascular (CV) risk assessment. Targeting only LDL-c could result in missed opportunities for CV risk reduction in T2DM patients. These data suggest that non-HDL-c, ApoB and oxidized LDL-c levels could be considered as an important part of these patients’ evaluation allowing for a more accurate estimation of CV risk and hopefully better management of these high-risk patients.

Apolipoprotein B is not superior to non-high-density lipoprotein cholesterol for dyslipidemic classification of glycated hemoglobin-defined diabetic patients

Low-density lipoprotein (LDL) cholesterol (LDL-C) always underestimates the true cholesterol burden in diabetic patients. We aimed to explore the impact of the inclusion of apolipoprotein B (apoB) or non-high-density lipoprotein (HDL) cholesterol (non-HDL-C), which are alternative markers of LDL-related risk, results in a better classification of glycated hemoglobin (HbA1c)-defined diabetic patients into different dyslipidemic phenotypes.We used data from the nationwide China Health and Nutrition Survey 2009 in which standardized HbA1c was measured.The prevalence of abnormal LDL using non-HDL-cholesterol (74.1%) was similar to the prevalence rate using LDL-C (75.2%), whereas the prevalence was relatively lower when using apoB (69.6%). In normotriglyceridemic HbA1c-defined diabetic patients, apoB and non-HDL-C were not superior to LDL-C in detecting abnormal LDL. However, in hypertriglyceridemic patients, apoB and non-HDL-C were superior to LDL-C for the detection of abnormal lipid levels, but apoB was not superior to non-HDL-C in detecting abnormal LDL in hypertriglyceridemic participants.Both apoB and non-HDL-C identify high-risk dyslipidemic phenotypes that are not detected by LDL-C in hypertriglyceridemic HbA1c-defined diabetic patients, with the superiority of non-HDL- C over apoB.

Hypovitaminosis D in type 2 diabetes: relation with features of the metabolic syndrome and glycemic control

AIM

To assess the association of hypovitaminosis D with clinical and biochemical characteristics of type 2 diabetic patients and to determine the effect of glycemic control optimization on 25-hydroxyvitamin D (25(OH)D) concentrations.

METHODS

Cross-sectional study of 63 patients with type 2 diabetes (mean age 60 ± 9.8 years, 69.8% men). Twenty of the 63 patients were also studied before and after glycemic control optimization.

RESULTS

Mean 25(OH)D concentrations were 63.64 ± 25.51 nmol/L and 74.6% of patients had hypovitaminosis D. Compared with patients with vitamin D sufficiency, patients with hypovitaminosis D had higher prevalence of overweight or obesity (72.3% versus 37.5%; p = 0.012) and higher VLDL cholesterol (VLDL-c) (0.71 (0.24-3.59) versus 0.45 (0.13-1.6) mmol/L; p = 0.011) and C-reactive protein (3.28 (0.36-17.69) versus 1.87 (0.18-17.47) mg/L; p = 0.033) concentrations. The composition of HDL particles also differed in both groups, with higher relative content of triglycerides and lower of cholesterol in patients with hypovitaminosis D. After adjustment for age, seasonality and BMI, differences remained significant for VLDL-c and triglyceride content of HDL. No differences were found regarding other diabetes characteristics. Improvement of glycemic control (HbA1c 9.4 (7.6-14.8) versus 7.3 (6.2-8.7)%; p = 0.000) was accompanied by a decrease in 25(OH)D concentrations (72.7 ± 33.3 to 59.0 ± 21.0 nmol/L; p = 0.035). Correlation analysis revealed that changes in 25(OH)D concentrations were negatively associated to changes in HbA1c (r - 0.482; p = 0.032).

CONCLUSION

Hypovitaminosis D is associated with features of the metabolic syndrome in type 2 diabetes and improvement of glycemic control decreases 25(OH)D concentrations.

Investigation on carbohydrate counting method in type 1 diabetic patients

OBJECTIVE

The results from Diabetes Control and Complications Trial (DCCT) have propounded the importance of the approach of treatment by medical nutrition when treating diabetes mellitus (DM). During this study, we tried to inquire carbohydrate (Kh) count method's positive effects on the type 1 DM treatment's success as well as on the life quality of the patients.

METHODS

22 of 37 type 1 DM patients who applied to Eskişehir Osmangazi University, Faculty of Medicine Hospital, Department of Endocrinology and Metabolism, had been treated by Kh count method and 15 of them are treated by multiple dosage intensive insulin treatment with applying standard diabetic diet as a control group and both of groups were under close follow-up for 6 months. Required approval was taken from the Ethical Committee of Eskişehir Osmangazi University, Medical Faculty, as well as informed consent from the patients. The body weight of patients who are treated by carbohydrate count method and multiple dosage intensive insulin treatment during the study beginning and after 6-month term, body mass index, and body compositions are analyzed. A short life quality and medical research survey applied. At statistical analysis, t-test, chi-squared test, and Mann-Whitney U test were used.

RESULTS

There had been no significant change determined at glycemic control indicators between the Kh counting group and the standard diabetic diet and multiple dosage insulin treatment group in our study.

CONCLUSION

As a result, Kh counting method which offers a flexible nutrition plan to diabetic individuals is a functional method.

Potential implications of the choice among three alternative treatment targets for apolipoprotein B100 in the management of patients with type 2 diabetes and chronic kidney disease

This study analyses discordance rates between attainment of therapeutic goals for apolipoprotein B100 (apoB) and both low-density lipoprotein-cholesterol (LDL-C) and non-high-density lipoprotein-cholesterol (non-HDL-C) in a sample of 152 patients with type 2 diabetes and chronic kidney disease from Gran Canaria (Spain), using treatment targets recommended by the American Diabetes Association/American College of Cardiology (ADA/ACC), the European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) and by a Spanish population-based study. Among subjects with LDL-C levels at therapeutic goal, apoB was above target in 16.3% (ADA/ACC), 6.5% (ESC/EAS) and 39.1% (population-based criteria), and among subjects with non-HDL-C levels at therapeutic goal, apoB was above target in 10.5% (ADA/ACC), 1.2% (ESC/EAS) and 29.6% (population-based criteria). These findings show that clinical management would be very differently altered depending on the criteria used to set treatment targets for apoB. Cut-off points derived from population data identify a greater number of subjects suitable for a more intensive lipid-lowering therapy.

Impact of the LDL subfraction phenotype on Lp-PLA2 distribution, LDL modification and HDL composition in type 2 diabetes

Background

Qualitative alterations of lipoproteins underlie the high incidence of atherosclerosis in diabetes. The objective of this study was to assess the impact of low-density lipoprotein (LDL) subfraction phenotype on the qualitative characteristics of LDL and high-density lipoprotein (HDL) in patients with type 2 diabetes.

Methods

One hundred twenty two patients with type 2 diabetes in poor glycemic control and 54 healthy subjects were included in the study. Patients were classified according to their LDL subfraction phenotype. Seventy-seven patients presented phenotype A whereas 45 had phenotype B. All control subjects showed phenotype A. Several forms of modified LDL, HDL composition and the activity and distribution of lipoprotein-associated phospholipase A2 (Lp-PLA2) were analyzed.

Results

Oxidized LDL, glycated LDL and electronegative LDL were increased in both groups of patients compared with the control group. Patients with phenotype B had increased oxidized LDL and glycated LDL concentration than patients with phenotype A. HDL composition was abnormal in patients with diabetes, being these abnormalities more marked in patients with phenotype B. Total Lp-PLA2 activity was higher in phenotype B than in phenotype A or in control subjects. The distribution of Lp-PLA2 between HDL and apoB-containing lipoproteins differed in patients with phenotype A and phenotype B, with higher activity associated to apoB-containing lipoproteins in the latter.

Conclusions

The presence of LDL subfraction phenotype B is associated with increased oxidized LDL, glycated LDL and Lp-PLA2 activity associated to apoB-containing lipoproteins, as well as with abnormal HDL composition.

Comparison of therapeutic lipid target achievements among high-risk patients in Oman

We compared therapeutic lipid target achievements among patients with diabetes or coronary heart disease (CHD) in Oman. A retrospective chart review of 94 patients was conducted at an outpatient clinic in Sultan Qaboos University Hospital, Muscat, Oman. The variables included low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and apolipoprotein B (apo B). The overall mean age of the cohort was 59 ± 12 years, 54% were male, 66% were diabetic, 48% hypertensive, 45% had CHD, 94% were on simvastatin, 4% were on fenofibrate, and 2% were on both simvastatin and fenofibrate. Lipid goal attainments of calculated LDL-C (<2.6 mmol/L), apo B (<0.9 g/L), and non-HDL-C (<3.36 mmol/L) were reached in 52%, 39%, and 53% of the patients, respectively. A significant proportion of high-risk patients treated with lipid-lowering agents reach LDL-C but not the apo B treatment targets, suggesting that the use of apo B target values should also be considered.

Discriminant ratio and biometrical equivalence of measured vs. calculated apolipoprotein B100 in patients with T2DM

BACKGROUND

Apolipoprotein B100 (ApoB100) determination is superior to low-density lipoprotein cholesterol (LDL-C) to establish cardiovascular (CV) risk, and does not require prior fasting. ApoB100 is rarely measured alongside standard lipids, which precludes comprehensive assessment of dyslipidemia.

OBJECTIVES

To evaluate two simple algorithms for apoB100 as regards their performance, equivalence and discrimination with reference apoB100 laboratory measurement.

METHODS

Two apoB100-predicting equations were compared in 87 type 2 diabetes mellitus (T2DM) patients using the Discriminant ratio (DR). Equation 1: apoB100 = 0.65*non-high-density lipoprotein cholesterol + 6.3; and Equation 2: apoB100 = -33.12 + 0.675*LDL-C + 11.95*ln[triglycerides]. The underlying between-subject standard deviation (SDU) was defined as SDU = √ (SD2B - SD2W/2); the within-subject variance (Vw) was calculated for m (2) repeat tests as (Vw) = Σ(xj -xi)2/(m-1)), the within-subject SD (SDw) being its square root; the DR being the ratio SDU/SDW.

RESULTS

All SDu, SDw and DR's values were nearly similar, and the observed differences in discriminatory power between all three determinations, i.e. measured and calculated apoB100 levels, did not reach statistical significance. Measured Pearson's product-moment correlation coefficients between all apoB100 determinations were very high, respectively at 0.94 (measured vs. equation 1); 0.92 (measured vs. equation 2); and 0.97 (equation 1 vs. equation 2), each measurement reaching unity after adjustment for attenuation.

CONCLUSION

Both apoB100 algorithms showed biometrical equivalence, and were as effective in estimating apoB100 from routine lipids. Their use should contribute to better characterize residual cardiometabolic risk linked to the number of atherogenic particles, when direct apoB100 determination is not available.

Is combination therapy an effective way of reaching lipid goals in type 2 diabetes mellitus?

Type 2 diabetes mellitus is associated with a specific pattern of plasma lipid and lipoprotein abnormalities. Lipid goals are often not attained with statins alone, and combination lipid-lowering strategies may need to be considered in an attempt to further reduce the residual cardiovascular risk. Combination therapy utilizes various classes of lipid-lowering medications with different mechanisms of action and different effects on lipid levels. Clinical trial data support the efficacy of combining statins with fibrates, niacin, ezetimibe (cholesterol absorption inhibitor) and colesevelam (bile acid sequestrant) with the caveat that there are insufficient clinical trial data to show a further robust benefit on cardiovascular outcomes. Of the different combination therapy options to potentiate low-density lipoprotein cholesterol lowering in combination with a statin, colesevelam provides additional beneficial effects by further reducing hemoglobin A1c levels in Type 2 diabetes mellitus.

Non-HDL-cholesterol as valid surrogate to apolipoprotein B100 measurement in diabetes: Discriminant Ratio and unbiased equivalence

Background

Apolipoprotein B₁₀₀ (apoB) is a superior indicator of CV risk than total or LDL-C. Non-HDL-C represents a simple surrogate for apoB in hypertriglyceridemic and/or T2DM patients. ApoB and non-HDL-C show high correlation, although the degree of mutual concordance remains debated in CV risk evaluation.

Objectives

We used the Discriminant Ratio (DR) methodology to compare the performance of non-HDL-C with that of apoB to rank diabetic patients according to dyslipidemia and to establish the underlying relationship between these variables taking measurement noise and intra-/intersubject variation into account, and to derive an unbiased equivalence equation.

Methods

Fasting total C, HDL-C, apoB and triglycerides were measured in 45 diabetic patients. The DR of the underlying between-subject standard deviation (SD) to the within-subject SD was calculated from duplicates. Correlation coefficients between pairs were adjusted to include an estimate of the underlying correlation.

Results

Mean values [day 1 (1SD)] were 143 (36) mg/dl (non-HDL-C) and 98 (24) mg/dl (apoB). The DR's of both parameters were similar (1.76 and 1.83) (p = 0.83). Pearson's product-moment correlation coefficient between tests was very high (0.94), reaching unity (1.00) after attenuation adjustment. The unbiased equation of equivalence relating apoB to non-HDL-C had a slope of 0.65 and an intercept of 6.3 mg/dl.

Conclusions

The discrimination power of non-HDL-C is similar to that of apoB to rank diabetic patients according to atherogenic cholesterol and lipoprotein burden. Since true correlation between variables reached unity, non-HDL-C may provide not only a metabolic surrogate but also a candidate biometrical equivalent to apoB, as non-HDL-C calculation is readily available.

Variability of lipids in patients with Type 2 diabetes taking statin treatment: implications for target setting

AIMS

To determine the biological variability of lipids in patients with Type 2 diabetes (T2DM) who are on statin treatment and then to assess any implications for current lipid targets.

METHODS

A cross-over study of biological variation of lipids in 26 patients with T2DM taking either simvastatin 40 mg or atorvastatin 10 mg. After 3 months on one statin, fasting lipids were measured on 10 occasions over a 5-week period. Following 3 months on the other statin, 10 further samples were taken over 5 weeks. The main outcome measures were biological variability of total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol and triglycerides.

RESULTS

The coefficient of variation (CV) of TC, LDL, HDL and triglycerides on simvastatin was 8.17, 13.11, 7.95 and 12.06%, respectively, whereas the CV on atorvastatin was 6.92, 10.30, 5.13 and 19.71%, respectively, with no statistically significant differences between statins. Treating to sustain a target TC < 5.0 mmol/l or LDL < 3.0 mmol/l means needing to maintain a mean TC of 4.3-4.4 mmol/l or LDL of 2.4-2.5 mmol/l. Treating to consistently achieve an LDL < 2.0 mmol/l means aiming for a mean of only 1.5-1.6 mmol/l.

CONCLUSION

In patients with T2DM taking either simvastatin or atorvastatin, the mean TC and LDL concentrations needed to consistently remain below a target are much lower than the target value itself. This means that guideline target limits extrapolated from the mean values of patients participating in clinical studies may overestimate the lipid reductions required.

Apolipoprotein B is a better marker than non-HDL-cholesterol for the metabolic syndrome in Koreans

Apolipoprotein B (apoB) concentration reflects the number of atherogenic particles and is closely associated with atherosclerosis. Non-HDL-cholesterol (non-HDL-C) has been considered a therapeutic target for patients with hypertriglyceridemia. We compared the predictive values of apoB and non-HDL-C for the metabolic syndrome (MetS) in 3335 Korean adults (mean age, 45.2 years) who participated consecutively in a health examination in a university hospital. Anthropometry, blood pressure, fasting glucose, lipid profiles and apoB were measured. MetS, as defined by a modification of the NCEP-ATP III criteria, was present in 22.1% of men and 16.1% of women. Among the components of the MetS, triglycerides showed the strongest correlation with apoB (r=0.393, P<0.001 in men, and r=0.326, P<0.001 in women) and non-HDL-C (r=0.376, P<0.001 in men, and r=0.349, P<0.001 in women). When apoB and non-HDL-C were mutually adjusted, the ORs for the MetS of non-HDL-C were not significant. As a function of the quartile of apoB levels, the ORs for the MetS were 2.04 (1.26-3.30), 3.54 (2.11-5.93), and 5.38 (3.16-9.17) in men (P for trend <0.001) and 3.75 (1.42-9.87), 5.55 (2.09-14.69), and 13.41 (5.02-35.79) in women (P for trend <0.001), respectively. These findings indicate that apoB is a better marker than non-HDL-C for identifying the MetS among Koreans.

Apolipoprotein A1 and B

This article reviews the evidence showing that apolipoprotein (apo) B and A-1 are superior to the conventional cholesterol indices as analytes in laboratory practice, indices of the lipoprotein-related risk for vascular disease, and measures of the adequacy of low-density lipoprotein-lowering therapy.

Management of dyslipidemia in diabetes

Diabetes is associated with a high risk of cardiovascular disease. The management of dyslipidemia, a well-recognized and modifiable risk factor among patients with type 2 diabetes, is an important element in the multifactorial approach to prevent coronary heart disease. Diabetic dyslipidemia typically consists of elevated triglyceride, low high-density lipoprotein cholesterol (HDL-C), and the predominance of small dense low-density lipoprotein (LDL) particles. LDL cholesterol (LDL-C) levels in patients with diabetes are similar to those found in the rest of the population. During the past few years, clinical trials have provided evidence that lipid-lowering therapy has a similar beneficial effect on cardiovascular outcomes in diabetic and nondiabetic individuals. According to current guidelines, the primary lipid target is an LDL-C <100 mg/dL (<70 mg/dL in very high-risk patients) and, to this end, statins are the agents of choice. The appropriate management of dyslipidemia in patients with diabetes, particularly in individuals with low LDL-C, remains controversial. To achieve lipid targets, attention should be directed first toward nonpharmacologic therapeutic interventions to control dyslipidemia, such as diet, exercise, smoking cessation, weight loss, and glycemic control. Statin therapy is recommended for most subjects but, frequently, a combination of lipid-lowering agents is required. A number of combinations are possible, and several factors should be considered to improve the safety of this strategy.

Apolipoprotein B as a long-term predictor of mortality in type 1 diabetes mellitus: a 15-year follow up

OBJECTIVES

To evaluate the association of apolipoprotein B (apo B) with mortality due to all causes, to cardiac disease and to ischaemic heart disease (IHD) in subjects with type 1 diabetes mellitus.

SUBJECTS

165 subjects with type 1 diabetes included in the Swiss Cohort of the WHO Multinational Study of Vascular Disease in Diabetes were followed for 14.7+/-0.45 years.

METHODS

Causes of death were obtained from death certificates, hospital records and postmortem reports. Using a parametric proportional hazards model the association of apo B with mortality rates was assessed by time-to-event analysis, including the absolute cumulative mortality risk over time for various apo B levels at baseline.

RESULTS

Apo B was positively associated with all-cause mortality [hazard ratio (HR) 2.65 per g L-1 increase of apo B, 95% CI: 1.11-6.36, P=0.029], cardiac mortality (HR 11.64, 1.03-131.11, P=0.047) and IHD mortality (HR 9.36, 1.26-69.66, P=0.029). An apo B>or=0.96 g L-1 translated into a duplication of overall mortality hazard (HR 1.93, 1.00-3.72, P=0.050), and a sevenfold increase of mortality because of cardiac disease or IHD (HR 7.44, 1.44-38.42, P=0.017 and HR 7.38, 0.78-69.82, P=0.081). A baseline apo B of 1.5 g L-1 predicted an absolute cumulative risk to die over the next 10 years of 12.1% (5.2-31.7) for male and of 10.4% (4.7-26.1) for female subjects whereas risks were 6.3% (1.8-21.4) and 5.4% (0.8-15.8) for an apo B of 0.8 g L-1.

CONCLUSION

Apo B is consistently associated with an increased mortality in type 1 diabetes.

Effect of age on the association of non-high-density-lipoprotein cholesterol and apolipoprotein B with cardiovascular mortality in a Mediterranean population with type 2 diabetes: the Casale Monferrato study

AIMS/HYPOTHESIS

Measurement of plasma apolipoprotein (Apo) B may improve prediction of cardiovascular risk, as it provides a measure of the total number of atherogenic particles. The aim of this population-based study was to compare the association of non-HDL-cholesterol, ApoB and the ApoB:ApoA-I ratio with cardiovascular mortality in people with type 2 diabetes.

SUBJECTS AND METHODS

We assessed the association of lipids, lipoprotein lipids and apolipoproteins with 11-year mortality from cardiovascular disease in the population-based cohort of the Casale Monferrato Study (1,565 people with diabetes; median age 68.9 years), and determined the effect of age (< or =70 and >70 years) on these relationships.

RESULTS

On the basis of 341 deaths from cardiovascular disease in 10,809 person-years of observation, there was a decreasing trend in risk adjusted for multiple factors across quartiles of total cholesterol, and LDL- and non-HDL-cholesterol in people aged >70 years, but no trend in those aged < or =70 years. Age did not affect the protective effect of HDL-cholesterol. ApoB and ApoB:ApoA-I were associated with outcome in people in both age groups independently of non-HDL-cholesterol. After adjustment for multiple factors, including non-HDL-cholesterol, the hazard ratios for ApoB:ApoA-I in the upper vs lower quartile were 2.98 (95% CI 1.15-7.75; p for trend=0.009) for people aged < or =70 years and 1.94 (95% CI 1.20-3.13; p for trend=0.003) for those aged >70 years.

CONCLUSIONS/INTERPRETATION

In this cohort of Mediterranean subjects with diabetes, ApoB and the ApoB:ApoA-I ratio were associated with cardiovascular disease mortality independently of non-HDL-cholesterol. Our findings support the recommendation that ApoB and ApoA-I should be measured routinely in all people with diabetes, particularly in the elderly.

Apo B versus cholesterol in estimating cardiovascular risk and in guiding therapy: report of the thirty-person/ten-country panel

There is abundant evidence that the risk of atherosclerotic vascular disease is directly related to plasma cholesterol levels. Accordingly, all of the national and transnational screening and therapeutic guidelines are based on total or LDL cholesterol. This presumes that cholesterol is the most important lipoprotein-related proatherogenic risk variable. On the contrary, risk appears to be more directly related to the number of circulating atherogenic particles that contact and enter the arterial wall than to the measured concentration of cholesterol in these lipoprotein fractions. Each of the atherogenic lipoprotein particles contains a single molecule of apolipoprotein (apo) B and therefore the concentration of apo B provides a direct measure of the number of circulating atherogenic lipoproteins. Evidence from fundamental, epidemiological and clinical trial studies indicates that apo B is superior to any of the cholesterol indices to recognize those at increased risk of vascular disease and to judge the adequacy of lipid-lowering therapy. On the basis of this evidence, we believe that apo B should be included in all guidelines as an indicator of cardiovascular risk. In addition, the present target adopted by the Canadian guideline groups of an apo B <90 mg dL(-1) in high-risk patients should be reassessed in the light of the new clinical trial results and a new ultra-low target of <80 mg dL(-1) be considered. The evidence also indicates that the apo B/apo A-I ratio is superior to any of the conventional cholesterol ratios in patients without symptomatic vascular disease or diabetes to evaluate the lipoprotein-related risk of vascular disease.

Comparison of the relationships between serum apolipoprotein B and serum lipid distributions

BACKGROUND

Apolipoprotein B (apo B) has been reported to be a better predictor of coronary artery disease than cholesterol indices. The objectives of this study were to evaluate concordances/discordances between cholesterol indices and apo B and to assess the factors that influence them.

METHODS

For this study, 11 816 individuals (6965 males, 4851 females), none of whom had a past history of coronary artery disease, were selected from among visitors to the health promotion center at Kangbuk Samsung Hospital between January and December 2002. We assessed concordances between the biochemical indices of atherogenicity and evaluated factors associated with discordances.

RESULTS

Apo B and various cholesterol indices were correlated, although concordance fell within the range 47%-56%. Multinomial logistic regression analysis showed an increasing risk of a disproportionately higher apo B than LDL-cholesterol in males, the elderly, smokers, individuals with metabolic syndrome, in those with high HDL-cholesterol or triglyceride (TG) concentrations or larger waist circumferences, and in those with low total cholesterol (TC).

CONCLUSIONS

The introduction of apo B to standard lipid profile testing could improve the evaluation of risk factors of coronary artery disease and aid more accurate assessment of the effects of cholesterol-lowering therapy, particularly in males, the elderly, smokers, or in individuals with metabolic syndrome, high HDL-cholesterol, high TGs, larger waist circumferences, or low TC.

Tesaglitazar, a novel dual peroxisome proliferator-activated receptor alpha/gamma agonist, dose-dependently improves the metabolic abnormalities associated with insulin resistance in a non-diabetic population

AIMS/HYPOTHESIS

Insulin resistance is associated with abnormalities in lipid and glucose metabolism, which are major components of metabolic syndrome and risk factors for vascular disease. This study examined the effect of tesaglitazar (Galida), a novel, dual-acting peroxisome proliferator-activated receptor alpha/gamma agonist, on lipid and glucose metabolism in patients with evidence of insulin resistance.

METHODS

A 12-week, multicentre, randomised, double-blind, placebo-controlled, dose-finding study compared the efficacy and safety of oral tesaglitazar (0.1, 0.25, 0.5 and 1.0 mg/day) and placebo in 390 non-diabetic patients with hypertriglyceridaemia (plasma triglyceride concentration >1.7 mmol/l) and abdominal obesity (waist-to-hip ratio >0.90 for men and >0.85 for women).

RESULTS

A 1.0-mg dose of tesaglitazar reduced fasting triglycerides (the primary endpoint) by 37% (95% CI: -43% to -30%; p<0.0001), non-HDL-cholesterol by 15% (95% CI: -20% to -10%; p<0.0001) and NEFA by 40% (95% CI: -51% to -27%; p<0.0001), and increased HDL-cholesterol by 16% (95% CI: 8 to -24%; p<0.0001). At the end of treatment there was a dose-dependent increase in patients with pattern A LDL particle diameter (40% at baseline vs 87% at 12 weeks for tesaglitazar 1.0 mg). Tesaglitazar produced significant reductions in fasting insulin concentration (-35%; p<0.0001) and plasma glucose concentration (-0.47 mmol/l; p<0.0001). Respiratory infection and gastrointestinal symptoms were the most common adverse events and were similarly frequent in all groups.

CONCLUSIONS/INTERPRETATION

Tesaglitazar was well tolerated and produced significant, dose-dependent improvements in lipid and glucose metabolism and insulin sensitivity. Tesaglitazar may have the potential to prevent vascular complications and delay progression to diabetes in these patients.

Association between insulin resistance and apolipoprotein B in normoglycemic Koreans

BACKGROUND

Insulin resistance (IR) is associated with a significant increase in the risk of coronary artery disease (CAD). The serum apolipoprotein B and Apo A1/Apo B ratio are important markers of CAD. The aim of this study was to assess the association of the serum Apo B and Apo A1/Apo B ratio, with insulin resistance in apparently healthy normoglycemic Koreans.

METHODS

From the individuals that participated in medical screening at the health promotion center of Kangbuk Samsung Hospital, between January and December 2002, a total of 7427 participants (4356 men, 3071 women) were enrolled in this study. All participants had no personal histories of diabetes, with normal fasting glucose levels. The clinical characteristics and biochemical parameters of the subjects were assessed.

RESULTS

The Apo B, total cholesterol/high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C)/high-density lipoprotein-cholesterol showed positive correlations with metabolic syndrome and insulin resistance (p<0.001). The Apo A1, Apo A1/Apo B, LDL/Apo B and HDL/Apo A1 showed negative correlations with metabolic syndrome and insulin resistance (p<0.001).

CONCLUSION

These data suggest that insulin resistance may be associated with the serum Apo B and Apo A1/Apo B ratio in non-diabetic, normoglycemic subjects. Thus, further study may be needed to determine whether medical intervention is inevitable or not in these type of subjects.

Management of diabetic dyslipidemia

Identification and management of dyslipidemia is an important element in the multi-factorial approach to prevent coronary heart disease. Diabetic dyslipidemia typically consists of elevated triglyceride, low high-density lipoprotein cholesterol, predominance of small, dense low-density lipoprotein (LDL) particles, and average LDL cholesterol (LDL-C). Lipid-lowering therapy has a beneficial effect on cardiovascular outcomes. Statin treatment is beneficial in patients who are older than 40 years of age, irrespective of the LDL-C value. To achieve lipid targets, attention should be directed first toward nonpharmacologic therapeutic interventions, such as diet, exercise, smoking cessation, weight loss, and improving glycemic control. Although statin therapy is recommended for most subjects, judicious use of combination therapy should be considered in the highest risk subjects.

The role of lipid management in diabetes

This article discusses the role of lipid management in diabetes.