Assessing the Accuracy of Estimated Lipoprotein(a) Cholesterol and Lipoprotein(a)-Free Low-Density Lipoprotein Cholesterol.

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.

Comparison of Methods to Estimate Low-Density Lipoprotein Cholesterol in Patients With High Triglyceride Levels.

Importance: Low-density lipoprotein cholesterol (LDL-C) is typically estimated with the Friedewald or Martin/Hopkins equation; however, if triglyceride levels are 400 mg/dL or greater, laboratories reflexively perform direct LDL-C (dLDL-C) measurement. The use of direct chemical LDL-C assays and estimation of LDL-C via the National Institutes of Health Sampson equation are not well validated, and data on the accuracy of LDL-C estimation at higher triglyceride levels are limited. Objective: To compare an extended Martin/Hopkins equation for triglyceride values of 400 to 799 mg/dL with the Friedewald and Sampson equations. Design, Setting, and Participants: This cross-sectional study evaluated consecutive patients at clinical sites across the US with patient lipid distributions representative of the US population in the Very Large Database of Lipids from January 1, 2006, to December 31, 2015, with triglyceride levels of 400 to 799 mg/dL. Data analysis was performed from November 9, 2020, to March 23, 2021. Main Outcomes and Measures: Accuracy in LDL-C classification according to guideline-based categories and absolute errors between estimated LDL-C and dLDL-C levels. Patients were randomly assigned 2:1 to derivation and validation data sets. Levels of dLDL-C were measured by vertical spin-density gradient ultracentrifugation. The LDL-C levels were estimated using the Friedewald method, with a fixed ratio of triglycerides to very low-density lipoprotein cholesterol (VLDL-C ratio of 5:1), extended Martin/Hopkins equation with a flexible ratio, and Sampson equation with VLDL-C estimation by multiple least-squares regression. Results: A total of 111 939 patients (mean [SD] age, 52 [13] years; 65.0% male) with triglyceride levels of 400 to 799 mg/dL were included, representing 2.2% of 5 081 680 patients in the database. Across all individual guideline LDL-C classes (<40, 40-69, 70-99, 100-129, 130-159, 160-189, and ≥190), estimation of LDL-C by the extended Martin/Hopkins equation was most accurate (62.1%) compared with the Friedewald (19.3%) and Sampson (40.4%) equations. In classifying LDL-C levels less than 70 mg/dL across all triglyceride strata, the extended Martin/Hopkins equation was most accurate (67.3%) compared with Friedewald (5.1%) and Sampson (26.4%) equations. In addition, for classifying LDL-C levels less than 40 mg/dL across all triglyceride strata, the extended Martin/Hopkins equation was most accurate (57.2%) compared with the Friedewald (4.3%) and Sampson (14.4%) equations. However, considerable underclassification of LDL-C occurred. The magnitude of error between the Martin/Hopkins equation estimation and dLDL-C was also smaller: at LDL-C levels less than 40 mg/dL, 2.7% of patients had 30 mg/dL or greater differences between dLDL-C and estimated LDL-C using the Martin/Hopkins equation compared with the Friedewald (92.5%) and Sampson (38.7%) equations. Conclusions and Relevance: In this cross-sectional study, the extended Martin/Hopkins equation offered greater LDL-C accuracy compared with the Friedewald and Sampson equations in patients with triglyceride levels of 400 to 799 mg/dL. However, regardless of method used, caution is advised with LDL-C estimation in this triglyceride range.

Utility of non-HDL-C and apoB targets in the context of new more aggressive lipid guidelines.

OBJECTIVE: Major guidelines recommend the use of secondary targets, such as non-HDL-C and apoB, to further reduce cardiovascular risk. We aimed to evaluate the proportion at which newer, more aggressive secondary lipid targets are exceeded in patients with LDL-C < 70 mg/dL estimated by Friedewald (LDLf-C) and Martin/Hopkins equations (LDLm-C). METHODS: We analyzed patients from the Very Large Database of Lipids with fasting lipids and estimated LDL-C <70 mg/dL by the Friedewald equation and Martin/Hopkins algorithm. Patients were categorized into three groups: LDL-C <40, 40-54 and 55-69 mg/dL. We calculated the proportion of patients with non-HDL-C and apoB above high-risk targets (non-HDL-C ≥ 100 and apoB ≥ 80mg/dL) for those with LDL-C 55-69 mg/dL and very high-risk targets (non-HDL-C ≥ 85 and apoB ≥ 65mg/dL) for those with LDL-C < 40 mg/dL and 40-54 mg/dL. RESULTS: In patients with LDLf-C < 40 mg/dL, ~8 and ~4% did not meet high-risk secondary targets and ~21 and 25% did not meet very high-risk secondary targets for non-HDL-C and apoB, respectively. However, in patients with LDLm-C < 40 mg/dL <1% did not meet high-risk targets, while only 3% did not meet the very-high risk secondary target for apoB and none exceeded the very-high risk secondary target for non-HDL-C. Among individuals with LDL-C< 40 mg/dL, there were increasing proportions of individuals not meeting the very high-risk secondary apoB target at greater triglyceride levels, reaching up to ~19% using LDLm-C compared to ~60% using LDLf-C when triglyceride levels were 200-399 mg/dL. There were higher proportions of individuals not meeting high and very-high risk targets as triglyceride levels increased among those with LDL-C 40-54 and 55-69 mg/dL. CONCLUSION: In a large, US cross-sectional sample of individuals with LDL-C < 70 mg/dL, secondary non-HDL-C and apoB targets overall provide modest utility. However, attainment of very high-risk cutpoints for non-HDL-C and apoB is not achieved in a significant fraction of patients with triglycerides 200-399 mg/dL, even when using a more accurate calculation of LDL-C.

Assessment of Coronary Artery Calcium Scoring to Guide Statin Therapy Allocation According to Risk-Enhancing Factors: The Multi-Ethnic Study of Atherosclerosis.

Importance: The 2018 American Heart Association/American College of Cardiology Guideline on the Management of Blood Cholesterol recommends the use of risk-enhancing factor assessment and the selective use of coronary artery calcium (CAC) scoring to guide the allocation of statin therapy among individuals with an intermediate risk of atherosclerotic cardiovascular disease (ASCVD). Objective: To examine the association between risk-enhancing factors and incident ASCVD by CAC burden among those at intermediate risk of ASCVD. Design, Setting, and Participants: The Multi-Ethnic Study of Atherosclerosis is a multicenter population-based prospective cross-sectional study conducted in the US. Baseline data for the present study were collected between July 15, 2000, and July 14, 2002, and follow-up for incident ASCVD events was ascertained through August 20, 2015. Participants were aged 45 to 75 years with no clinical ASCVD or diabetes at baseline, were at intermediate risk of ASCVD (≥7.5% to <20.0%), and had a low-density lipoprotein cholesterol level of 70 to 189 mg/dL. Exposures: Family history of premature ASCVD, premature menopause, metabolic syndrome, chronic kidney disease, lipid and inflammatory biomarkers, and low ankle-brachial index. Main Outcomes and Measures: Incident ASCVD over a median follow-up of 12.0 years. Results: A total of 1688 participants (mean [SD] age, 65 [6] years; 976 men [57.8%]). Of those, 648 individuals (38.4%) were White, 562 (33.3%) were Black, 305 (18.1%) were Hispanic, and 173 (10.2%) were Chinese American. A total of 722 participants (42.8%) had a CAC score of 0. Among those with 1 to 2 risk-enhancing factors vs those with 3 or more risk-enhancing factors, the prevalence of a CAC score of 0 was 45.7% vs 40.3%, respectively. Over a median follow-up of 12.0 years (interquartile range [IQR], 11.5-12.6 years), the unadjusted incidence rate of ASCVD among those with a CAC score of 0 was less than 7.5 events per 1000 person-years for all individual risk-enhancing factors (with the exception of ankle-brachial index, for which the incidence rate was 10.4 events per 1000 person-years [95% CI, 1.5-73.5]) and combinations of risk-enhancing factors, including participants with 3 or more risk-enhancing factors. Although the individual and composite addition of risk-enhancing factors to the traditional risk factors was associated with improvement in the area under the receiver operating curve, the use of CAC scoring was associated with the greatest improvement in the C statistic (0.633 vs 0.678) for ASCVD events. For incident ASCVD, the net reclassification improvement for CAC was 0.067. Conclusions and Relevance: In this cross-sectional study, among participants with CAC scores of 0, the presence of risk-enhancing factors was generally not associated with an overall ASCVD risk that was higher than the recommended treatment threshold for the initiation of statin therapy. The use of CAC scoring was associated with significant improvements in the reclassification and discrimination of incident ASCVD. The results of this study support the utility of CAC scoring as an adjunct to risk-enhancing factor assessment to more accurately classify individuals with an intermediate risk of ASCVD who might benefit from statin therapy.

Importance of the triglyceride level in identifying patients with a Type III Hyperlipoproteinemia phenotype using the ApoB algorithm.

BACKGROUND: Hyperlipoproteinemia Type III (HLP3), also known as dysbetalipoproteinemia, is defined by cholesterol and triglyceride (TG) enriched remnant lipoprotein particles (RLP). The gold standard for diagnosis requires demonstration of high remnant lipoprotein particle cholesterol (RLP-C) by serum ultracentrifugation (UC), which is not readily available in daily practice. The apoB algorithm can identify HLP3 using total cholesterol (TC), plasma triglyceride (TG), and apoB. However, the optimal TG cutoff is unknown. OBJECTIVE: We analyzed apoB algorithm defined HLP3 at different TG levels to optimize the TG cutoff for the algorithm. METHODS: 128,485 UC lipid profiles in the Very Large Database of Lipids (VLDbL) were analyzed. RLP-C was assessed at TG ≥ 133 mg/dL, ≥175 mg/dL, ≥200 mg/dL, and ≥ 250 mg/dL. Sensitivity (Sn), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and prevalence adjusted and bias-adjusted kappa (PABAK) were calculated against UC Criterion (VLDL-C/TG ≥ 0.25) for HLP3. RESULTS: The median age (IQR) was 57 years (46-68). 45% were men, 20.1% had diabetes, and 25.5% had hypertension. The median RLP-C level for the TG cutoffs (mg/dL) of ≥ 133, ≥ 175, ≥ 200, and ≥ 250 were 34, 43, 50, and 62 mg/dL, respectively, compared to 67 mg/dL in UC defined HLP3. TG ≥ 133 mg/dL yielded optimal results (Sn 29.5%, Sp 98.5%, PABAK 0.96, PPV 13.6%, NPV 99.4%). CONCLUSION: TG ≥ 133 mg/dL allows for high sensitivity in screening for HLP3. Higher TG cutoffs may identify more severe HLP3 phenotypes, but with a large loss in sensitivity for HLP3.

Modern prevalence of the Fredrickson-Levy-Lees dyslipidemias: findings from the Very Large Database of Lipids and National Health and Nutrition Examination Survey.

INTRODUCTION: Five decades ago, Fredrickson, Levy, and Lees (FLL) qualitatively characterized clinical dyslipidemias with specific implications for cardiovascular and non-cardiovascular morbidity and mortality. They separated disorders of elevated cholesterol and triglycerides into five phenotypes (types I-V) based on their lipoprotein profile. Although clinicians generally consider them rare entities, modern FLL prevalence may be greater than previously reported. MATERIAL AND METHODS: We performed a cross-sectional analysis in 5,272 participants from the 2011-2014 National Health and Nutrition Examination Survey and 128,506 participants from the Very Large Database of Lipids study with complete, fasting lipid profiles. We used a validated algorithm to define FLL phenotypes employing apolipoprotein B, total cholesterol, and triglycerides. RESULTS: Overall prevalence of FLL phenotypes was 33.9%. FLL prevalence in the general population versus clinical lipid database was: type I (0.05 vs. 0.02%), type IIa (3.2 vs. 3.9%), type IIb (8.0 vs. 10.3%), type III (2.0 vs. 1.7%), type IV (20.5 vs. 24.1%), and type V (0.15 vs. 0.13%). Those aged 40-74 years had a higher overall prevalence compared to other age groups (p < 0.001) and men had overall higher prevalence than women (p < 0.001). Those with diabetes (51.6%) or obese BMI (49.0%) had higher prevalence of FLL phenotypes compared to those without diabetes (31.3%; p < 0.001) and normal BMI (18.3%; p < 0.001). CONCLUSIONS: FLL phenotypes are likely far more prevalent than appreciated in clinical practice, in part due to diabetes and obesity epidemics. Given the prognostic and therapeutic importance of these phenotypes, their identification becomes increasingly important in the era of precision medicine.

Modern prevalence of dysbetalipoproteinemia (Fredrickson-Levy-Lees type III hyperlipoproteinemia).

INTRODUCTION: Dysbetalipoproteinaemia (HLP3) is a disorder characterized by excess cholesterol-enriched, triglyceride-rich lipoprotein remnants in genetically predisposed individuals that powerfully promote premature cardiovascular disease if untreated. The current prevalence of HLP3 is largely unknown. MATERIAL AND METHODS: We performed cross-sectional analysis of 128,485 U.S. adults from the Very Large Database of Lipids (VLDbL), using four algorithms to diagnose HLP3 employing three Vertical Auto Profile ultracentrifugation (UC) criteria and a previously described apolipoprotein B (apoB) method. We evaluated 4,926 participants from the 2011-2014 National Health and Nutrition Examination Survey (NHANES) with the apoB method. We examined demographic and lipid characteristics stratified by presence of HLP3 and evaluated lipid characteristics in those with HLP3 phenotype discordance and concordance as determined by apoB and originally defined UC criteria 1. RESULTS: In U.S. adults in VLDbL and NHANES, a 1.7-2.0% prevalence is observed for HLP3 with the novel apoB method as compared to 0.2-0.8% prevalence in VLDbL via UC criteria 1-3. Participants who were both apoB and UC criteria HLP3 positive had higher remnant particles as well as more elevated triglyceride/apoB and total cholesterol/apoB ratios (all p < 0.001) than those who were apoB method positive and UC criteria 1 negative. CONCLUSIONS: HLP3 may be more prevalent than historically and clinically appreciated. The apoB method increases HLP3 identification via inclusion of milder phenotypes. Further work should evaluate the clinical implications of HLP3 diagnosis at various lipid algorithm cut-points to evaluate the ideal standard in the modern era.

Clinical significance of zero coronary artery calcium in individuals with LDL cholesterol ≥190 mg/dL: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND AND AIMS: Individuals with low-density lipoprotein cholesterol (LDL-C) ≥190 mg/dL are considered high-risk and current guidelines recommend initiating high-intensity statin therapy in this group. We sought to examine the predictive ability of zero CAC in this high-risk group. METHODS: Multi-Ethnic Study of Atherosclerosis participants without clinical cardiovascular disease and baseline LDL-C ≥190 mg/dL were identified. Cardiovascular risk factors were compared between those with CAC = 0 and CAC >0. Multivariable Poisson regression was used to identify predictors of CAC = 0. Association of CAC = 0 with incident cardiovascular events over a median follow-up of 13.2 years was examined using multivariable-adjusted Cox regression. RESULTS: 246 individuals (mean age = 63 ±â€¯9.4 years; 42% male; 31% white; 37% CAC = 0) with LDL-C ≥190 mg/dL were identified (mean LDL-C = 215 ±â€¯27 mg/dL). Age <65 years (RR = 2.17, 95%CI = 1.49-3.23), female sex (RR = 2.10, 95%CI = 1.42-3.10), and no diabetes (RR = 2.22, 95%CI = 1.18-4.17) were associated with CAC = 0. Individuals with CAC = 0 had a lower risk for future cardiovascular events (incidence rate per 1000 person-years = 4.7; 10-year risk = 3.7%; risk/year = 0.4%) than those with CAC >0 (incidence rate per 1000 person-years = 26.4; 10-year risk = 20%; risk/year = 2.0%), adjusted HR 0.25 (95%CI = 0.10-0.66). CONCLUSIONS: Among persons with LDL-C ≥190 mg/dL, younger age, female sex, and the absence of diabetes were associated with CAC = 0. CAC = 0 was associated with a low risk of cardiovascular events, suggesting the utility of CAC assessment for stratifying risk in this high-risk group.

Impact of improved low-density lipoprotein cholesterol assessment on guideline classification in the modern treatment era-Results from a racially diverse Brazilian cross-sectional study.

BACKGROUND: The Martin/Hopkins low-density lipoprotein cholesterol equation (LDL-CN) was previously demonstrated as more accurate than Friedewald LDL-C estimation (LDL-CF) in a North American database not able to take race into account. OBJECTIVES: We hypothesized that LDL-CN would be more accurate than LDL-CF and correlate better with LDL particle number (LDL-P) in a racially diverse Brazilian cohort. METHODS: We performed a cross-sectional analysis of 4897 participants in the Brazilian Longitudinal Study of Adult Health, assessing LDL-CF and LDL-CN accuracy via overlap with ultracentrifugation-based measurement among clinical guideline LDL-C categories as well as mg/dL and percent error differences. We analyzed by triglyceride categories and correlated LDL-C estimation with LDL-P. RESULTS: LDL-CN demonstrated improved accuracy at 70 to <100 and <70 mg/dL (P < .001), with large errors ≥20 mg/dL about 9 times more frequent in LDL-CF at LDL-C <70 mg/dL, mainly due to underestimation. Among individuals with LDL-C <70 mg/dL and triglycerides ≥150 mg/dL, 65% vs 100% of ultracentrifugation-based low-density lipoprotein cholesterol calculation fell within appropriate categories of estimated LDL-CF and LDL-CN, respectively (P < .001). Similar results were observed when analyzed for age, sex, and race. Participants at LDL-C <70 and 70 to <100 mg/dL with discordantly elevated LDL-CN vs LDL-CF had a 58.5% and 41.5% higher LDL-P than those with concordance (P < .0001), respectively. CONCLUSIONS: In a diverse Brazilian cohort, LDL-CN was more accurate than LDL-CF at low LDL-C and high triglycerides. LDL-CN may avoid underestimation of LDL-C and better reflect atherogenic lipid burden in low particle size, high particle count states.

Novel Therapeutic Targets for Managing Dyslipidemia.

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of morbidity and mortality in developed nations. Therapeutic modulation of dyslipidemia by inhibiting 3'-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase is standard practice throughout the world. However, based on findings from Mendelian studies and genetic sequencing in prospective longitudinal cohorts from around the world, novel therapeutic targets regulating lipid and lipoprotein metabolism, such as apoprotein C3, angiopoietin-like proteins 3 and 4, and lipoprotein(a), have been identified. These targets may provide additional avenues to prevent and treat atherosclerotic disease. We therefore review these novel molecular targets by addressing available Mendelian and observational data, therapeutic agents in development, and early outcomes results.

Impact of Novel Low-Density Lipoprotein-Cholesterol Assessment on the Utility of Secondary Non-High-Density Lipoprotein-C and Apolipoprotein B Targets in Selected Worldwide Dyslipidemia Guidelines.

BACKGROUND: Selected dyslipidemia guidelines recommend non-high-density lipoprotein-cholesterol (non-HDL-C) and apolipoprotein B (apoB) as secondary targets to the primary target of low-density lipoprotein-cholesterol (LDL-C). After considering 2 LDL-C estimates that differ in accuracy, we examined: (1) how frequently non-HDL-C guideline targets could change management; and (2) the utility of apoB targets after meeting LDL-C and non-HDL-C targets. METHODS: We analyzed 2518 adults representative of the US population from the 2011 to 2012 National Health and Nutrition Examination Survey and 126 092 patients from the Very Large Database of Lipids study with apoB. We identified all individuals as well as those with high-risk clinical features, including coronary artery disease, diabetes mellitus, and metabolic syndrome who met very high- and high-risk guideline targets of LDL-C <70 and <100 mg/dL using Friedewald estimation (LDL-CF) and a novel, more accurate method (LDL-CN). Next, we examined those not meeting non-HDL-C (<100, <130 mg/dL) and apoB (<80, <100 mg/dL) guideline targets. In those meeting dual LDL-C and non-HDL-C targets (<70 and <100 mg/dL, respectively, or <100 and <130 mg/dL, respectively), we determined the proportion of individuals who did not meet guideline apoB targets (<80 or <100 mg/dL). RESULTS: A total of 7% to 9% and 31% to 36% of individuals had LDL-C <70 and <100 mg/dL, respectively. Among those with LDL-CF<70 mg/dL, 14% to 15% had non-HDL-C ≥100 mg/dL, and 7% to 8% had apoB ≥80 mg/dL. Among those with LDL-CF<100 mg/dL, 8% to 10% had non-HDL-C ≥130 mg/dL and 2% to 3% had apoB ≥100 mg/dL. In comparison, among those with LDL-CN<70 or 100 mg/dL, only ≈2% and ≈1% of individuals, respectively, had non-HDL-C and apoB values above guideline targets. Similar trends were upheld among those with high-risk clinical features: ≈0% to 3% of individuals with LDL-CN<70 mg/dL had non-HDL-C ≥100 mg/dL or apoB ≥80 mg/dL compared with 13% to 38% and 9% to 25%, respectively, in those with LDL-CF<70 mg/dL. With LDL-CF or LDL-CN<70 mg/dL and non-HDL-C <100 mg/dL, 0% to 1% had apoB ≥80 mg/dL. Among all dual LDL-CF or LDL-CN<100 mg/dL and non-HDL-C <130 mg/dL individuals, 0% to 0.4% had apoB ≥100 mg/dL. These findings were robust to sex, fasting status, and lipid-lowering therapy status. CONCLUSIONS: After more accurately estimating LDL-C, guideline-suggested non-HDL-C targets could alter management in only a small fraction of individuals, including those with coronary artery disease and other high-risk clinical features. Furthermore, current guideline-suggested apoB targets provide modest utility after meeting cholesterol targets. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01698489.

Fasting Versus Nonfasting and Low-Density Lipoprotein Cholesterol Accuracy.

BACKGROUND: Recent recommendations favoring nonfasting lipid assessment may affect low-density lipoprotein cholesterol (LDL-C) estimation. The novel method of LDL-C estimation (LDL-CN) uses a flexible approach to derive patient-specific ratios of triglycerides to very low-density lipoprotein cholesterol. This adaptability may confer an accuracy advantage in nonfasting patients over the fixed approach of the classic Friedewald method (LDL-CF). METHODS: We used a US cross-sectional sample of 1 545 634 patients (959 153 fasting ≥10-12 hours; 586 481 nonfasting) from the second harvest of the Very Large Database of Lipids study to assess for the first time the impact of fasting status on novel LDL-C accuracy. Rapid ultracentrifugation was used to directly measure LDL-C content (LDL-CD). Accuracy was defined as the percentage of LDL-CD falling within an estimated LDL-C (LDL-CN or LDL-CF) category by clinical cut points. For low estimated LDL-C (<70 mg/dL), we evaluated accuracy by triglyceride levels. The magnitude of absolute and percent differences between LDL-CD and estimated LDL-C (LDL-CN or LDL-CF) was stratified by LDL-C and triglyceride categories. RESULTS: In both fasting and nonfasting samples, accuracy was higher with the novel method across all clinical LDL-C categories (range, 87%-94%) compared with the Friedewald estimation (range, 71%-93%; P≤0.001). With LDL-C <70 mg/dL, nonfasting LDL-CN accuracy (92%) was superior to LDL-CF accuracy (71%; P<0.001). In this LDL-C range, 19% of fasting and 30% of nonfasting patients had differences ≥10 mg/dL between LDL-CF and LDL-CD, whereas only 2% and 3% of patients, respectively, had similar differences with novel estimation. Accuracy of LDL-C <70 mg/dL further decreased as triglycerides increased, particularly for Friedewald estimation (range, 37%-96%) versus the novel method (range, 82%-94%). With triglycerides of 200 to 399 mg/dL in nonfasting patients, LDL-CN <70 mg/dL accuracy (82%) was superior to LDL-CF (37%; P<0.001). In this triglyceride range, 73% of fasting and 81% of nonfasting patients had ≥10 mg/dL differences between LDL-CF and LDL-CD compared with 25% and 20% of patients, respectively, with LDL-CN. CONCLUSIONS: Novel adaptable LDL-C estimation performs better in nonfasting samples than the fixed Friedewald estimation, with a particular accuracy advantage in settings of low LDL-C and high triglycerides. In addition to stimulating further study, these results may have immediate relevance for guideline committees, laboratory leadership, clinicians, and patients. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01698489.

Damage Control Plating in Open Tibial Shaft Fractures: A Cheaper and Equally Effective Alternative to Spanning External Fixation.

The purpose of this study was to evaluate damage control plating (DCP) as an alternative to external fixation (EF) in the provisional stabilization of open tibial shaft fractures. Through retrospective analysis, the study found 445 patients who underwent operative fixation for tibial shaft fractures from 2008 to 2012. Twenty patients received DCP or EF before intramedullary nailing with a minimum follow-up of 3 months. Charts and radiographs were reviewed for postoperative complications. Hospital charges were reviewed for implant costs. Nine patients (45%) with DCP and 11 patients (55%) with EF were analyzed. There was no significant difference in the complication rates. The mean implant cost of DCP was $1028, whereas mean EF construct cost was $4204. Therefore, DCP resulted in significant cost savings with no difference in complication rates, making it a valuable alternative to EF for the provisional stabilization of open tibial shaft fractures.

Does Physician Reimbursement Correlate to Risk in Orthopaedic Trauma?

This study investigated whether current Medicare reimbursements for orthopaedic trauma procedures correlate with complications. A total of 18,510 patients representing 33 orthopaedic trauma procedures from 2005 to 2011 were studied. Adverse events and Medicare payments for each orthopaedic trauma procedure were collected. Linear regressions determined correlations between complications and Medicare payments for orthopaedic trauma procedures. A weak correlation between Medicare payments and complications was found for all procedures (r = .399, p = .021). A 1.0% increase in complications was associated with a payment increase of only $100. There were no correlations between complications and reimbursements for upper extremity (p = .878) and lower extremity (p = .713) procedures. A strong correlation (r = .808, p = .015) existed for hip and pelvic fractures, but a 1.1% increase in hip and pelvic complications correlated with only an increase of $100 in reimbursements. This study is the first to show that Medicare payments are not strongly correlated with complications, therefore demonstrating the potential risks of a bundled payment system for orthopaedic trauma surgeons.

Addressing Knowledge Gaps in the 2013 ACC/AHA Guideline on the Assessment of Cardiovascular Risk: a Review of Recent Coronary Artery Calcium Literature.

PURPOSE OF REVIEW: Coronary artery calcium (CAC) has been proposed as an integrator of information from traditionally measured, non-traditionally measured, and unmeasured risk factors for coronary atherosclerosis. The 2013 American College of Cardiology/American Heart Association Guideline on the Assessment of Cardiovascular Risk identified several knowledge gaps regarding CAC, including radiation risks, cost-effectiveness, and improving discrimination and reclassification of estimated risk over the Pooled Cohort Equations in the ACC/AHA Atherosclerotic Cardiovascular Disease Estimator. In this review, we focus on recent CAC literature addressing these knowledge gaps. We further highlight the potential for CAC to enrich future randomized controlled trials. RECENT FINDINGS: The use of CAC allows for personalization of cardiovascular risk despite the presence or absence of traditional risk factors across many demographics. Avenues to reduce radiation exposure associated with CAC scanning include increasing the interval between scans for those with CAC scores of zero and estimating CAC from non-cardiac gated CT scans. While limited studies have suggested cost-effectiveness in cardiac risk assessment with the incorporation of CAC in screening algorithms, several studies have demonstrated the ability of CAC to identify non-traditional risk factors that may be used to expand cardiovascular risk personalization in other high-risk populations. Literature from the past 2 years further supports CAC as a strong marker to personalize cardiac risk assessment. While multiple potential avenues to reduce radiation are available and cost-effectiveness analyses are encouraging, further studies are necessary to clarify patient selection for CAC scanning given the interplay between CAC and other imaging modalities in risk personalization algorithms.