Accuracy of low-density lipoprotein cholesterol estimation at very low levels.
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ABSTRACT:
SUBMITTER: Quispe R
PROVIDER: S-EPMC5399386 | biostudies-literature | 2017 Apr
REPOSITORIES: biostudies-literature
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Accuracy of low-density lipoprotein cholesterol estimation at very low levels.
Quispe Renato R Hendrani Aditya A Elshazly Mohamed B MB Michos Erin D ED McEvoy John W JW Blaha Michael J MJ Banach Maciej M Kulkarni Krishnaji R KR Toth Peter P PP Coresh Josef J Blumenthal Roger S RS Jones Steven R SR Martin Seth S SS
BMC medicine 20170420 1
<h4>Background</h4>As the approach to low-density lipoprotein cholesterol (LDL-C) lowering becomes increasingly intensive, accurate assessment of LDL-C at very low levels warrants closer attention in individualized clinical efficacy and safety evaluation. We aimed to assess the accuracy of LDL-C estimation at very low levels by the Friedewald equation, the de facto clinical standard, and compare its accuracy with a novel, big data-derived LDL-C estimate.<h4>Methods</h4>In 191,333 individuals wit ...[more]
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Project description:Background Accurate measurement of the cholesterol within lipoprotein(a) (Lp[a]-C) and its contribution to low-density lipoprotein cholesterol (LDL-C) has important implications for risk assessment, diagnosis, and treatment of atherosclerotic cardiovascular disease, as well as in familial hypercholesterolemia. A method for estimating Lp(a)-C from particle number using fixed conversion factors has been proposed (Lp[a]-C from particle number divided by 2.4 for Lp(a) mass, multiplied by 30% for Lp[a]-C). The accuracy of this method, which theoretically can isolate "Lp(a)-free LDL-C," has not been validated. Methods and Results In 177 875 patients from the VLDbL (Very Large Database of Lipids), we compared estimated Lp(a)-C and Lp(a)-free LDL-C with measured values and quantified absolute and percent error. We compared findings with an analogous data set from the Mayo Clinic Laboratory. Error in estimated Lp(a)-C and Lp(a)-free LDL-C increased with higher Lp(a)-C values. Median error for estimated Lp(a)-C <10 mg/dL was -1.9 mg/dL (interquartile range, -4.0 to 0.2); this error increased linearly, overestimating by +30.8 mg/dL (interquartile range, 26.1-36.5) for estimated Lp(a)-C ≥50 mg/dL. This error relationship persisted after stratification by overall high-density lipoprotein cholesterol and high-density lipoprotein cholesterol subtypes. Similar findings were observed in the Mayo cohort. Absolute error for Lp(a)-free LDL-C was +2.4 (interquartile range, -0.6 to 5.3) for Lp(a)-C<10 mg/dL and -31.8 (interquartile range, -37.8 to -26.5) mg/dL for Lp(a)-C≥50 mg/dL. Conclusions Lp(a)-C estimations using fixed conversion factors overestimated Lp(a)-C and subsequently underestimated Lp(a)-free LDL-C, especially at clinically relevant Lp(a) values. Application of inaccurate Lp(a)-C estimations to correct LDL-C may lead to undertreatment of high-risk patients.
| S-EPMC9238537 | biostudies-literature
Project description:ImportanceIn the Cholesterol Treatment Trialists Collaboration (CTTC), in patients starting with low-density lipoprotein cholesterol (LDL-C) levels of approximately 3.4 mmol/L (131.5 mg/dL), there was a 22% reduction in major vascular events per 1-mmol/L (38.7-mg/dL) lowering of LDL-C. The magnitude of clinical benefit of further LDL-C lowering in patients already with very low LDL-C levels remains debated.ObjectiveTo evaluate efficacy and safety of further lowering LDL-C levels in patient populations presenting with median LDL-C levels of 1.8 mmol/L (70 mg/dL) or less.Data sources and study selectionThe CTTC was used for statin data. For nonstatin therapy, Medline database was searched (2015-April 2018). Key inclusion criteria were a randomized, double-blind, controlled cardiovascular outcome trial of LDL-C lowering with data in populations starting with LDL-C levels averaging 1.8 mmol/L (70 mg/dL) or less.Data extraction and synthesisTwo authors independently extracted data into standardized data sheets, and data were analyzed using meta-analysis.Main outcomes and measuresThe risk ratio (RR) of major vascular events (a composite of coronary heart death, myocardial infarction, ischemic stroke, or coronary revascularization) per 1-mmol/L (38.7-mg/dL) reduction in LDL-C level.ResultsIn the subgroup of patients from the CTTC meta-analysis of statins with a mean LDL-C in the control arm of 1.7 mmol/L (65.7 mg/dL), 1922 major vascular events occurred and the RR for major vascular events per 1-mmol/L (38.7-mg/dL) reduction in LDL-C was 0.78 (95% CI, 0.65-0.94). For 3 trials of nonstatin LDL-C-lowering therapies added to statins, there were 50 627 patients, the median LDL-C in the control arms ranged from 1.6 mmol/L to 1.8 mmol/L (63 mg/dL to 70 mg/dL), and 9570 major vascular events occurred. Nonstatin therapy lowered LDL-C by 0.3 to 1.2 mmol/L (11 mg/dL to 45 mg/dL), and the RR for major vascular events per 1-mmol/L (38.7-mg/dL) reduction in LDL-C was 0.79 (95% CI, 0.70-0.88). For statins and nonstatins combined, the RR was 0.79 (95% CI, 0.71-0.87; P < .001). Low-density lipoprotein cholesterol lowering was not associated with an increased risk of serious adverse events, myalgias and/or myositis, elevation in the level of aminotransferases, new-onset diabetes, hemorrhagic stroke, or cancer.Conclusions and relevanceThere is a consistent relative risk reduction in major vascular events per change in LDL-C in patient populations starting as low as a median of 1.6 mmol/L (63 mg/dL) and achieving levels as low as a median of 0.5 mmol/L (21 mg/dL), with no observed offsetting adverse effects. These data suggest further lowering of LDL-C beyond the lowest current targets would further reduce cardiovascular risk.
| S-EPMC6233651 | biostudies-literature
Project description:While recent genomic studies have focused attention on triglyceride (TG) rich lipoproteins in cardiovascular disease (CVD), little is known of very low-density lipoprotein cholesterol (VLDL-C) relationship with atherosclerosis and CVD. We examined, in a high-risk type-2 diabetic population, the association of plasma VLDL-C with coronary artery calcification (CAC).The Penn Diabetes Heart Study (PDHS) is a cross-sectional study of CVD risk factors in type-2 diabetics (n = 2118, mean age 59.1 years, 36.5% female, 34.1% Black). Plasma lipids including VLDL-C were calculated (n = 1879) after ultracentrifugation.In Tobit regression, VLDL-C levels were positively associated with increasing CAC after adjusting for age, race, gender, Framingham risk score, body mass index, C-reactive protein, exercise, medication and alcohol use, hemoglobin A1c, and diabetes duration [Tobit ratio (TR) and 95% confidence interval (CI) 0.38 (0.12-0.65), P = 0.005] and even after inclusion of apolipoprotein B data [TR 0.31 (0.03-0.58), P = 0.030]. Approximately 3-fold stronger effect was observed in women [TR 0.75 (0.16-1.34), P = 0.013] than men [TR 0.20 (-0.10-0.50), P = 0.189; gender interaction P = 0.034]. Plasma VLDL-C was related more strongly to CAC scores than TG levels (e.g., Akaike information criteria of 7263.65 vs. 7263.94) and had stronger CAC association in individuals with TGs >150 mg/dl (TR 0.80, P = 0.010) vs. those with TGs <150 mg/dl (TR 0.27, P = 0.185).In PDHS, VLDL-C is associated with CAC independent of established CVD risk factors, particularly in women, and may have value even beyond apolipoprotein B levels and in patients with elevated TGs.
| S-EPMC4209900 | biostudies-literature
Project description:Very low-density lipoprotein cholesterol (VLDL-C), via binding very low-density lipoprotein receptor (VLDLR), can induce the development of atherosclerosis. Besides monocytes, VLDLR expression is detected in various peripheral white blood cells (WBCs), yet its underlying role remains unclear. We thereby aimed to test the hypothesis that VLDLR in all types of peripheral WBCs may be involved in the association between VLDL-C and atherosclerosis. VLDLR mRNA expression in peripheral WBC and plasma VLDL-C levels were measured in 747 participants from a community-based study. Plaque prevalence and total plaque area (TPA) were used to evaluate the burden of carotid atherosclerosis. VLDL-C was positively associated with atherosclerosis risk, whereas this association was modified by VLDLR mRNA level. In participants with the lowest VLDL-C but the highest VLDLR mRNA expression, the risk for plaque prevalence unexpectedly was the highest. This association was also observed for TPA. Moreover, this association remained unchanged after adjusting for WBC or monocytes. Our findings described an atherogenic phenotype characterized by low VLDL-C but high VLDLR mRNA expression in peripheral WBCs, which suggested that VLDLR in all types of peripheral WBCs may be involved in lipid deposition, and VLDL-C and VLDLR may co-determine the development of atherosclerosis.
| S-EPMC5704045 | biostudies-literature
Project description:Importance:In the Improved Reduction of Outcomes: Vytorin Efficacy International Trial, intensive low-density lipoprotein cholesterol (LDL-C)-reducing therapy with ezetimibe/simvastatin compared with simvastatin alone was associated with a significant reduction in cardiovascular events in 18?144 patients after acute coronary syndrome. The safety of very low LDL-C levels over the long-term is unknown. Objective:To assess the safety and clinical efficacy of achieving a very low (<30 mg/dL) level of LDL-C at 1 month using data from the Improved Reduction of Outcomes: Vytorin Efficacy International Trial. Design, Setting, and Participants:This prespecified analysis compared outcomes in patients stratified by achieved LDL-C level at 1 month in the Improved Reduction of Outcomes: Vytorin Efficacy International Trial and adjusted for baseline characteristics during 6 years' median follow-up. Patients were enrolled from October 26, 2005, to July 8, 2010, and the data analysis was conducted from December 2014 to February 2017. Main Outcomes and Measures:Safety end points included adverse events leading to drug discontinuation; adverse muscle, hepatobiliary, and neurocognitive events; and hemorrhagic stroke, heart failure, cancer, and noncardiovascular death. Efficacy events were as specified in the overall trial. Results:Among the 15?281 patients included in the study, 11?645 (76.2%) were men and the median age was 63 years (interquartile range, 56.6-70.7 years). In these patients without an event in the first month, the achieved LDL-C values at 1 month were less than 30 mg/dL, 30 to 49 mg/dL, 50 to 69 mg/dL, and 70 mg/dL or greater in 6.4%, 31%, 36%, and 26% of patients, respectively. Patients with LDL-C values less than 30 mg/dL (median, 25 mg/dL; interquartile range, 21-27 mg/dL) at 1 month were more likely randomized to ezetimibe/simvastatin (85%), had lower baseline LDL-C values, and were more likely older, male, nonwhite, diabetic, overweight, statin naive, and presenting with a first myocardial infarction. After multivariate adjustment, there was no significant association between the achieved LDL-C level and any of the 9 prespecified safety events. The adjusted risk of the primary efficacy composite of cardiovascular death, major coronary events, or stroke was significantly lower in patients achieving an LDL-C level less than 30 mg/dL at 1 month (adjusted hazard ratio, 0.79; 95% CI, 0.69-0.91; P?=?.001) compared with 70 mg/dL or greater. Conclusions and Relevance:Patients achieving an LDL-C level less than 30 mg/dL at 1 month had a similar safety profile (and numerically the lowest rate of cardiovascular events) over a 6-year period compared with patients achieving higher LDL-C concentrations. These data provide reassurance regarding the longer-term safety and efficacy of the continuation of intensive lipid-lowering therapy in very higher-risk patients resulting in very low LDL-C levels. Trial Registration:clinicaltrials.gov Identifier: NCT00202878.
| S-EPMC5814987 | biostudies-literature
Project description:Dengue virus (DENV) is a flavivirus of worldwide importance, with approximately 4 billion people across 128 countries at risk of infection, and up to 390 million infections and 96 million clinically apparent cases estimated annually. Previous in vitro studies have shown that lipids and lipoproteins play a role in modifying virus infectivity. However, the relationship between development of severe dengue and total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), respectively, is unclear. We analyzed data from 789 laboratory-confirmed dengue cases and 447 other febrile illnesses (OFI) in a prospective pediatric hospital-based study in Managua, Nicaragua between August 2005 and January 2013, using three different classifications of dengue severity: World Health Organization (WHO) 1997, WHO 2009, and standardized intervention categories. Total serum cholesterol and LDL-C levels decreased over the course of illness and were generally lower with increasing dengue severity, regardless of classification scheme. Greater decreases in LDL-C than HDL-C were observed among dengue-positive patients compared to patients with OFI and among severe dengue compared to mild dengue cases. Furthermore, daily cholesterol levels declined with daily albumin blood levels. To examine the effect of cholesterol at presentation on subsequent risk of development of severe dengue, relative risks and 95% confidence intervals were calculated using multivariable modified Poisson models. We found that lower total serum cholesterol and LDL-C levels at presentation were associated with subsequent risk of developing dengue hemorrhagic fever/dengue shock syndrome using the WHO 1997 dengue severity classification, and thus that the reduction in LDL-C is likely driving the decreases observed in total serum cholesterol levels among dengue-positive patients. Our results suggest that cholesterol blood levels are important correlates of dengue pathophysiology and should be explored as part of a prognostic biomarker panel for severe dengue.
| S-EPMC4559460 | biostudies-literature
Project description:We aimed to test the association between low-density lipoprotein cholesterol (LDL-C) and cardiovascular disease (CVD), cancer, and all-cause mortality in non-statin users. A total of 347,971 subjects in Kangbuk Samsung Health Study (KSHS.57.4% men, mean follow up: 5.64 ± 3.27 years) were tested. To validate these associations, we analyzed data from another cohort (Korean genome and epidemiology study, KoGES, 182,943 subjects). All subjects treated with any lipid-lowering therapy and who died during the first 3 years of follow up were excluded. Five groups were defined according to baseline LDL-C concentration (<70, 70-99, 100-129, 130-159, ?160 mg/dL). A total of 2028 deaths occurred during follow-up in KSHS. The lowest LDL-C group (LDL < 70 mg/dL) had a higher risk of all-cause mortality (HR 1.95, 1.55-2.47), CVD mortality (HR 2.02, 1.11-3.64), and cancer mortality (HR 2.06, 1.46-2.90) compared to the reference group (LDL 120-139 mg/dL). In the validation cohort, 2338 deaths occurred during follow-up. The lowest LDL-C group (LDL < 70 mg/dL) had a higher risk of all-cause mortality (HR 1.81, 1.44-2.28) compared to the reference group. Low levels of LDL-C concentration are strongly and independently associated with increased risk of cancer, CVD, and all-cause mortality. These findings suggest that more attention is needed for subjects with no statin-induced decrease in LDL-C concentrations.
| S-EPMC6832139 | biostudies-literature
Project description:BackgroundThe total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) ratio, estimated low-density lipoprotein cholesterol (LDL-C), and non-HDL-C are routinely available from the standard lipid profile. We aimed to assess the extent of patient-level discordance of TC/HDL-C with LDL-C and non-HDL-C, because discordance suggests the possibility of additional information.Methods and resultsWe compared population percentiles of TC/HDL-C, Friedewald-estimated LDL-C, and non-HDL-C in 1 310 432 US adults from the Very Large Database of Lipids. Lipid testing was performed by ultracentrifugation (Vertical Auto Profile, Atherotech, AL). One in 3 patients had ≥25 percentile units discordance between TC/HDL-C and LDL-C, whereas 1 in 4 had ≥25 percentile units discordance between TC/HDL-C and non-HDL-C. The proportion of patients with TC/HDL-C > LDL-C by ≥25 percentile units increased from 3% at triglycerides <100 mg/dL to 51% at triglycerides 200 to 399 mg/dL. On a smaller scale, TC/HDL-C > non-HDL-C discordance by ≥25 percentile units increased from 6% to 21%. In those with <15th percentile levels of LDL-C (<70 mg/dL) or non-HDL-C (<93 mg/dL), a respective 58% and 46% were above the percentile-equivalent TC/HDL-C of 2.6. Age, sex, and directly measured components of the standard lipid profile explained >86% of the variance in percentile discordance between TC/HDL-C versus LDL-C and non-HDL-C.ConclusionsIn this contemporary, cross-sectional, big data analysis of US adults who underwent advanced lipid testing, the extent of patient-level discordance suggests that TC/HDL-C may offer potential additional information to LDL-C and non-HDL-C. Future studies are required to determine the clinical implications of this observation.Clinical trial registrationURL: http://www.clinicaltrials.gov. Unique identifier: NCT01698489.
| S-EPMC4550508 | biostudies-literature
Project description:To study potential effects of hepatic cholesterol concentration on secretion of very-low-density lipoprotein (VLDL) by the liver, male rats were fed on unsupplemented chow, chow with lovastatin (0.1%), or chow with lovastatin (0.1%) and cholesterol (0.1%) for 1 week. Livers were isolated from these animals and perfused in vitro, with a medium containing [2-14C]acetate, bovine serum albumin and glucose in Krebs-Henseleit buffer, and with an oleate-albumin complex. With lovastatin feeding, the hepatic concentrations of cholesteryl esters and triacylglycerols before perfusion were decreased, although free cholesterol was unchanged. However, hepatic secretion of all the VLDL lipids was decreased dramatically by treatment with lovastatin. Although total secretion of VLDL triacylglycerol, phospholipid, cholesterol and cholesteryl esters was decreased, the decrease in triacylglycerol was greater than that in free cholesterol or cholesteryl esters, resulting in secretion of a VLDL particle enriched in sterols relative to triacylglycerol. In separate studies, the uptake of VLDL by livers from control animals or animals treated with lovastatin was measured. Uptake of VLDL was estimated by disappearance of VLDL labelled with [1-14C]oleate in the triacylglycerol moiety, and was observed to be similar in both groups. During perfusion, triacylglycerol accumulated to a greater extent in livers from lovastatin-fed rats than in control animals. The depressed output of VLDL triacylglycerols and the increase in triacylglycerol in the livers from lovastatin-treated animals was indicative of a limitation in the rate of VLDL secretion. Addition of cholesterol (either free cholesterol or human low-density lipoprotein) to the medium perfusing livers from lovastatin-fed rats, or addition of cholesterol to the diet of lovastatin-fed rats, increased the hepatic concentration of cholesteryl esters and the output of VLDL lipids. The concentration of cholesteryl esters in the liver was correlated with the secretion of VLDL by the liver. These data suggest that cholesterol is an obligate component of the VLDL required for its secretion. It is additionally suggested that cholesteryl esters are in rapid equilibrium with a small pool of free cholesterol which comprises a putative metabolic pool available and necessary for the formation and secretion of the VLDL. Furthermore, the specific radioactivity (d.p.m./mumol) of the secreted VLDL free cholesterol was much greater than that of hepatic free cholesterol, suggesting that the putative hepatic metabolic pool is only a minor fraction of total hepatic free cholesterol.
| S-EPMC1138436 | biostudies-other
Project description:Background The role of bacteria on the onset of cardiovascular disease has been suggested. Reciprocally, increased intestinal bacterial translocation and bloodstream infection are common comorbidities associated with heart failure and myocardial infarction (MI). In this context, the aim of this study was to analyze the blood microbiome in patients shortly after acute myocardial infarction. Methods and Results We carried out a case control study comparing 103 patients at high cardiovascular risk but free of coronary disease and 99 patients who had an MI. The blood microbiome was analyzed both quantitatively by 16S quantitative polymerase chain reaction and qualitatively by 16S targeted metagenomic sequencing specifically optimized for blood samples. A significant increase in blood bacterial 16S rDNA concentration was observed in patients admitted for MI. This increase in blood bacterial DNA concentration was independent of post-MI left ventricular function and was more marked in patients with low-density lipoprotein cholesterol ?1 g/L. In addition, differences in the proportion of numerous bacterial taxa in blood were significantly modified with the onset of MI, thus defining a blood microbiota signature of MI. Among the bacterial taxa whose proportions are decreased in patients with MI, at least 6 are known to include species able to metabolize cholesterol. Conclusions These results could provide the basis for the identification of blood microbiome-based biomarkers for the stratification of MI patients. Furthermore, these findings should provide insight into the mechanism underlying the negative correlation reported between low-density lipoprotein cholesterol concentration and the prognosis at the acute onset of MI and mortality. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02405468.
| S-EPMC6806051 | biostudies-literature