Higher docosahexaenoic acid levels lower the protective impact of eicosapentaenoic acid on long-term major cardiovascular events

Introduction

Long-chain omega-3 polyunsaturated fatty acids (OM3 PUFA) are commonly used for cardiovascular disease prevention. High-dose eicosapentaenoic acid (EPA) is reported to reduce major adverse cardiovascular events (MACE); however, a combined EPA and docosahexaenoic acid (DHA) supplementation has not been proven to do so. This study aimed to evaluate the potential interaction between EPA and DHA levels on long-term MACE.

Methods

We studied a cohort of 987 randomly selected subjects enrolled in the INSPIRE biobank registry who underwent coronary angiography. We used rapid throughput liquid chromatography-mass spectrometry to quantify the EPA and DHA plasma levels and examined their impact unadjusted, adjusted for one another, and fully adjusted for comorbidities, EPA + DHA, and the EPA/DHA ratio on long-term (10-year) MACE (all-cause death, myocardial infarction, stroke, heart failure hospitalization).

Results

The average subject age was 61.5 ± 12.2 years, 57% were male, 41% were obese, 42% had severe coronary artery disease (CAD), and 311 (31.5%) had a MACE. The 10-year MACE unadjusted hazard ratio (HR) for the highest (fourth) vs. lowest (first) quartile (Q) of EPA was HR = 0.48 (95% CI: 0.35, 0.67). The adjustment for DHA changed the HR to 0.30 (CI: 0.19, 0.49), and an additional adjustment for baseline differences changed the HR to 0.36 (CI: 0.22, 0.58). Conversely, unadjusted DHA did not significantly predict MACE, but adjustment for EPA resulted in a 1.81-fold higher risk of MACE (CI: 1.14, 2.90) for Q4 vs. Q1. However, after the adjustment for baseline differences, the risk of MACE was not significant for DHA (HR = 1.37; CI: 0.85, 2.20). An EPA/DHA ratio ≥1 resulted in a lower rate of 10-year MACE outcomes (27% vs. 37%, adjusted p-value = 0.013).

Conclusions

Higher levels of EPA, but not DHA, are associated with a lower risk of MACE. When combined with EPA, higher DHA blunts the benefit of EPA and is associated with a higher risk of MACE in the presence of low EPA. These findings can help explain the discrepant results of EPA-only and EPA/DHA mixed clinical supplementation trials.

A highly predictive cardiac positron emission tomography (PET) risk score for 90-day and one-year major adverse cardiac events and revascularization

BACKGROUND

With the increase in cardiac PET/CT availability and utilization, the development of a PET/CT-based major adverse cardiovascular events, including death, myocardial infarction (MI), and revascularization (MACE-Revasc) risk assessment score is needed. Here we develop a highly predictive PET/CT-based risk score for 90-day and one-year MACE-Revasc.

METHODS AND RESULTS

11,552 patients had a PET/CT from 2015 to 2017 and were studied for the training and development set. PET/CT from 2018 was used to validate the derived scores (n = 5049). Patients were on average 65 years old, half were male, and a quarter had a prior MI or revascularization. Baseline characteristics and PET/CT results were used to derive the MACE-Revasc risk models, resulting in models with 5 and 8 weighted factors. The PET/CT 90-day MACE-Revasc risk score trended toward outperforming ischemic burden alone [P = .07 with an area under the curve (AUC) 0.85 vs 0.83]. The PET/CT one-year MACE-Revasc score was better than the use of ischemic burden alone (P < .0001, AUC 0.80 vs 0.76). Both PET/CT MACE-Revasc risk scores outperformed risk prediction by cardiologists.

CONCLUSION

The derived PET/CT 90-day and one-year MACE-Revasc risk scores were highly predictive and outperformed ischemic burden and cardiologist assessment. These scores are easy to calculate, lending to straightforward clinical implementation and should be further tested for clinical usefulness.

Absent or Mild Coronary Calcium Predicts Low-Risk Stress Test Results and Outcomes in Patients Considered for Flecainide Therapy

BACKGROUND

Flecainide is a useful antiarrhythmic for atrial fibrillation (AF). However, because of ventricular proarrhythmia risk, a history of myocardial infarction (MI) or coronary artery disease (CAD) is a flecainide exclusion, and stress testing is used to exclude ischemia. We assessed whether absent/mild coronary artery calcium (CAC) can supplement or avoid the need for stress testing.

METHODS

We assessed ischemic burden using regadenoson Rb-82 PET/CT in 1372 AF patients ≥50 years old without symptoms or signs of clinical CAD. CAC was determined qualitatively by low dose attenuation computed tomography (CT) (n = 816) or by quantitative CT (n = 556). Ischemic burden and clinical outcomes were compared by CAC burden.

RESULTS

Patients with CAC absent or mild (n = 766, 57.2%) were younger, more frequently female, and had higher BMI but lower rates of diabetes, hypertension, and dyslipidemia. Average ischemic burden was lower in CAC-absent/mild patients, and CAC-absent/mild patients showed greater coronary flow reserve, had fewer referrals for coronary angiography, and less often had obstructive CAD. Revascularization at 90 days was lower, and the rate of longer-term major adverse cardiovascular events was favorable.

CONCLUSIONS

An easily administered, inexpensive, low radiation CAC scan can identify a subset of flecainide candidates with a low ischemic burden on PET stress testing that rarely needs coronary angiography/intervention and has favorable outcomes. Absent or mild CAC-burden combined with other clinical information may avoid or complement routine stress testing. However, additional, ideally randomized and multicenter trials are indicated to confirm these findings before replacing stress testing with CAC screening in selecting patients for flecainide therapy in clinical practice.

Association of Factor V Leiden With Subsequent Atherothrombotic Events: A GENIUS-CHD Study of Individual Participant Data

BACKGROUND

Studies examining the role of factor V Leiden among patients at higher risk of atherothrombotic events, such as those with established coronary heart disease (CHD), are lacking. Given that coagulation is involved in the thrombus formation stage on atherosclerotic plaque rupture, we hypothesized that factor V Leiden may be a stronger risk factor for atherothrombotic events in patients with established CHD.

METHODS

We performed an individual-level meta-analysis including 25 prospective studies (18 cohorts, 3 case-cohorts, 4 randomized trials) from the GENIUS-CHD (Genetics of Subsequent Coronary Heart Disease) consortium involving patients with established CHD at baseline. Participating studies genotyped factor V Leiden status and shared risk estimates for the outcomes of interest using a centrally developed statistical code with harmonized definitions across studies. Cox proportional hazards regression models were used to obtain age- and sex-adjusted estimates. The obtained estimates were pooled using fixed-effect meta-analysis. The primary outcome was composite of myocardial infarction and CHD death. Secondary outcomes included any stroke, ischemic stroke, coronary revascularization, cardiovascular mortality, and all-cause mortality.

RESULTS

The studies included 69 681 individuals of whom 3190 (4.6%) were either heterozygous or homozygous (n=47) carriers of factor V Leiden. Median follow-up per study ranged from 1.0 to 10.6 years. A total of 20 studies with 61 147 participants and 6849 events contributed to analyses of the primary outcome. Factor V Leiden was not associated with the combined outcome of myocardial infarction and CHD death (hazard ratio, 1.03 [95% CI, 0.92-1.16]; I2=28%; P-heterogeneity=0.12). Subgroup analysis according to baseline characteristics or strata of traditional cardiovascular risk factors did not show relevant differences. Similarly, risk estimates for the secondary outcomes including stroke, coronary revascularization, cardiovascular mortality, and all-cause mortality were also close to identity.

CONCLUSIONS

Factor V Leiden was not associated with increased risk of subsequent atherothrombotic events and mortality in high-risk participants with established and treated CHD. Routine assessment of factor V Leiden status is unlikely to improve atherothrombotic events risk stratification in this population.

Comparison of Three Atherosclerotic Cardiovascular Disease Risk Scores With and Without Coronary Calcium for Predicting Revascularization and Major Adverse Coronary Events in Symptomatic Patients Undergoing Positron Emission Tomography-Stress Testing

Atherosclerotic cardiovascular disease (ASCVD) is the most important cause of morbidity and mortality nationally and internationally. Improving ASCVD risk prediction is a high clinical priority. We sought to determine which of 3 ASCVD risk scores best predicts the need for revascularization and incident major adverse coronary events (MACE) in symptomatic patients at low-to-intermediate primary ASCVD risk referred for regadenoson-stress positron emission tomography (PET). Risk scores included the standard ASCVD pooled cohort equation (PCE), the multiethnic study of atherosclerosis (MESA) risk equation, and the coronary artery calcium score (CACS), obtained by PET. All qualifying patients in our institution at primary ASCVD risk referred for PET-stress tests in whom PCE, MESA, and CAC scores could be calculated were studied. CACS categories were: 0, 1 to 10, 11 to 299, 300 to 999, and 1000+. MESA and PCE scores were divided into quartiles. Logistic regression modeling was used to predict clinical/PET-driven early revascularization (within 90 days) and 1-year MACE (death, myocardial infarction, or any-time revascularization). A total of 981 patients (54% men, age 67 ± 10 years) qualified and were studied. Scores including CAC (MESA, CACS) performed better than PCE for predicting overall 1-year MACE (MESA p <0.001, CACS p = 0.012 vs PCE), which was driven by early revascularization. In conclusion, in a large population of patients at primary ASCVD risk referred for PET-stress testing, risk scores including CAC (CACS, MESA), which better predicted early revascularization and 1-year MACE, may be particularly useful in primary coronary risk assessment when considering whom to refer for PET-stress testing.

Absence of Coronary Artery Calcium During Positron Emission Tomography Stress Testing in Patients Without Known Coronary Artery Disease Identifies Individuals With Very Low Risk of Cardiac Events

Background:

Myocardial perfusion imaging, including positron emission tomography/computed tomography (PET/CT), is often used to assess for high-grade coronary artery disease (CAD) requiring revascularization. The use of coronary artery calcium (CAC) to predict risk of major adverse cardiovascular events in asymptomatic patients is accepted. However, little is known regarding the use of CAC in PET/CT patients without known CAD in identifying patients unlikely to need revascularization. Here, we determined whether the absence of CAC, using low-dose attenuation correction CT obtained during the PET/CT, identifies patients unlikely to undergo coronary revascularization within 90 days of a PET/CT.

Methods:

Patients, without a history of CAD and no elevation in troponin, referred for PET/CT at Intermountain Medical Center were studied (n=5528). The presence of CAC was visually assessed using low-dose attenuation correction CT. The association between CAC and 90-day high-grade CAD and revascularization were assessed. Longer-term (up to 4 years) major adverse cardiovascular events, including all-cause death, myocardial infarction, and late revascularization (>90 days), were examined.

Results:

There were 2510 (45.4%) patients in CAC-present group and 3018 (54.6%) patients in CAC-absent group. The CAC-absent group, compared with the CAC-present group, was less likely to undergo coronary angiography (3.4% versus 10.2%, P <0.0001), have high-grade CAD (0.5% versus 6.5%, P <0.0001), and receive revascularization (0.4% versus 5.8%, [adjusted odds ratio =0.09; 95% CI, 0.05–0.16]; P <0.0001). In patients with an ischemic burden >10%, the CAC-absent group was associated with reduced revascularization ( P <0.0001). Longer-term major adverse cardiovascular events were lower in the CAC-absent (2.4%) compared with the CAC-present (6.9%) group (adjusted hazard ratio, 0.45 [95% CI, 0.34–0.60]; P <0.0001).

Conclusions:

The absence of CAC on low-dose attenuation correction CT identifies PET/CT patients unlikely to have high-grade CAD or require revascularization within 90 days and unlikely to experience longer-term major adverse cardiovascular events. The prognostic value of CAC, beyond ischemic burden, suggests its potential as a first-step screening tool in intermediate-risk patients to identify those who do not need coronary revascularization.

Subsequent Event Risk in Individuals With Established Coronary Heart Disease

Supplemental Digital Content is available in the text.

Background:

The Genetics of Subsequent Coronary Heart Disease (GENIUS-CHD) consortium was established to facilitate discovery and validation of genetic variants and biomarkers for risk of subsequent CHD events, in individuals with established CHD.

Methods:

The consortium currently includes 57 studies from 18 countries, recruiting 185 614 participants with either acute coronary syndrome, stable CHD, or a mixture of both at baseline. All studies collected biological samples and followed-up study participants prospectively for subsequent events.

Results:

Enrollment into the individual studies took place between 1985 to present day with a duration of follow-up ranging from 9 months to 15 years. Within each study, participants with CHD are predominantly of self-reported European descent (38%–100%), mostly male (44%–91%) with mean ages at recruitment ranging from 40 to 75 years. Initial feasibility analyses, using a federated analysis approach, yielded expected associations between age (hazard ratio, 1.15; 95% CI, 1.14–1.16) per 5-year increase, male sex (hazard ratio, 1.17; 95% CI, 1.13–1.21) and smoking (hazard ratio, 1.43; 95% CI, 1.35–1.51) with risk of subsequent CHD death or myocardial infarction and differing associations with other individual and composite cardiovascular endpoints.

Conclusions:

GENIUS-CHD is a global collaboration seeking to elucidate genetic and nongenetic determinants of subsequent event risk in individuals with established CHD, to improve residual risk prediction and identify novel drug targets for secondary prevention. Initial analyses demonstrate the feasibility and reliability of a federated analysis approach. The consortium now plans to initiate and test novel hypotheses as well as supporting replication and validation analyses for other investigators.

Association of Chromosome 9p21 With Subsequent Coronary Heart Disease Events

Supplemental Digital Content is available in the text.

Background:

Genetic variation at chromosome 9p21 is a recognized risk factor for coronary heart disease (CHD). However, its effect on disease progression and subsequent events is unclear, raising questions about its value for stratification of residual risk.

Methods:

A variant at chromosome 9p21 (rs1333049) was tested for association with subsequent events during follow-up in 103 357 Europeans with established CHD at baseline from the GENIUS-CHD (Genetics of Subsequent Coronary Heart Disease) Consortium (73.1% male, mean age 62.9 years). The primary outcome, subsequent CHD death or myocardial infarction (CHD death/myocardial infarction), occurred in 13 040 of the 93 115 participants with available outcome data. Effect estimates were compared with case/control risk obtained from the CARDIoGRAMplusC4D consortium (Coronary Artery Disease Genome-wide Replication and Meta-analysis [CARDIoGRAM] plus The Coronary Artery Disease [C4D] Genetics) including 47 222 CHD cases and 122 264 controls free of CHD.

Results:

Meta-analyses revealed no significant association between chromosome 9p21 and the primary outcome of CHD death/myocardial infarction among those with established CHD at baseline (GENIUS-CHD odds ratio, 1.02; 95% CI, 0.99–1.05). This contrasted with a strong association in CARDIoGRAMPlusC4D odds ratio 1.20; 95% CI, 1.18–1.22; P for interaction <0.001 compared with the GENIUS-CHD estimate. Similarly, no clear associations were identified for additional subsequent outcomes, including all-cause death, although we found a modest positive association between chromosome 9p21 and subsequent revascularization (odds ratio, 1.07; 95% CI, 1.04–1.09).

Conclusions:

In contrast to studies comparing individuals with CHD to disease-free controls, we found no clear association between genetic variation at chromosome 9p21 and risk of subsequent acute CHD events when all individuals had CHD at baseline. However, the association with subsequent revascularization may support the postulated mechanism of chromosome 9p21 for promoting atheroma development.

Practical laboratory-based clinical decision tools and associations with short-term bleeding and mortality outcomes

BACKGROUND

The red cell distribution width (RDW) predicts mortality in numerous populations. The Intermountain Risk Scores (IMRS) predict patient outcomes using laboratory measurements including RDW. Whether the RDW or IMRS predicts in-hospital outcomes is unknown.

METHODS

The predictive abilities of RDW and two IMRS formulations (the complete blood count [CBC] risk score [CBC-RS] or full IMRS using CBC plus the basic metabolic profile) were studied among percutaneous coronary intervention patients at Intermountain (males: N = 6007, females: N = 2165). Primary endpoints were a composite bleeding outcome and in-hospital mortality.

RESULTS

IMRS predicted the composite bleeding endpoint (females: χ² = 47.1, odds ratio [OR] = 1.13 per +1 score, p < 0.001; males: χ² = 108.7, OR = 1.13 per +1 score, p < 0.001) more strongly than RDW (females: χ² = 1.6, OR = 1.04 per +1%, p = 0.20; males: χ² = 11.2, OR = 1.09 per +1%, p < 0.001). For in-hospital mortality, RDW was predictive in females (χ² = 4.3, OR = 1.13 per +1%, p = 0.037) and males (χ² = 4.4, OR = 1.11 per +1%, p = 0.037), but IMRS was profoundly more predictive (females: χ² = 35.5, OR = 1.36 per +1 score, p < 0.001; males: χ² = 72.9, OR = 1.40 per+1 score, p < 0.001). CBC-RS was more predictive than RDW but not as powerful as IMRS.

CONCLUSIONS

The IMRS, the CBC-RS, and RDW predict in-hospital outcomes. Risk score-directed personalization of in-hospital clinical care should be studied.

Impact of Selection Bias on Estimation of Subsequent Event Risk

BACKGROUND

Studies of recurrent or subsequent disease events may be susceptible to bias caused by selection of subjects who both experience and survive the primary indexing event. Currently, the magnitude of any selection bias, particularly for subsequent time-to-event analysis in genetic association studies, is unknown.

METHODS AND RESULTS

We used empirically inspired simulation studies to explore the impact of selection bias on the marginal hazard ratio for risk of subsequent events among those with established coronary heart disease. The extent of selection bias was determined by the magnitudes of genetic and nongenetic effects on the indexing (first) coronary heart disease event. Unless the genetic hazard ratio was unrealistically large (>1.6 per allele) and assuming the sum of all nongenetic hazard ratios was <10, bias was usually <10% (downward toward the null). Despite the low bias, the probability that a confidence interval included the true effect decreased (undercoverage) with increasing sample size because of increasing precision. Importantly, false-positive rates were not affected by selection bias.

CONCLUSIONS

In most empirical settings, selection bias is expected to have a limited impact on genetic effect estimates of subsequent event risk. Nevertheless, because of undercoverage increasing with sample size, most confidence intervals will be over precise (not wide enough). When there is no effect modification by history of coronary heart disease, the false-positive rates of association tests will be close to nominal.

Relations between lipoprotein(a) concentrations, LPA genetic variants, and the risk of mortality in patients with established coronary heart disease: a molecular and genetic association study

BACKGROUND

Lipoprotein(a) concentrations in plasma are associated with cardiovascular risk in the general population. Whether lipoprotein(a) concentrations or LPA genetic variants predict long-term mortality in patients with established coronary heart disease remains less clear.

METHODS

We obtained data from 3313 patients with established coronary heart disease in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. We tested associations of tertiles of lipoprotein(a) concentration in plasma and two LPA single-nucleotide polymorphisms ([SNPs] rs10455872 and rs3798220) with all-cause mortality and cardiovascular mortality by Cox regression analysis and with severity of disease by generalised linear modelling, with and without adjustment for age, sex, diabetes diagnosis, systolic blood pressure, BMI, smoking status, estimated glomerular filtration rate, LDL-cholesterol concentration, and use of lipid-lowering therapy. Results for plasma lipoprotein(a) concentrations were validated in five independent studies involving 10 195 patients with established coronary heart disease. Results for genetic associations were replicated through large-scale collaborative analysis in the GENIUS-CHD consortium, comprising 106 353 patients with established coronary heart disease and 19 332 deaths in 22 studies or cohorts.

FINDINGS

The median follow-up was 9·9 years. Increased severity of coronary heart disease was associated with lipoprotein(a) concentrations in plasma in the highest tertile (adjusted hazard radio [HR] 1·44, 95% CI 1·14-1·83) and the presence of either LPA SNP (1·88, 1·40-2·53). No associations were found in LURIC with all-cause mortality (highest tertile of lipoprotein(a) concentration in plasma 0·95, 0·81-1·11 and either LPA SNP 1·10, 0·92-1·31) or cardiovascular mortality (0·99, 0·81-1·2 and 1·13, 0·90-1·40, respectively) or in the validation studies.

INTERPRETATION

In patients with prevalent coronary heart disease, lipoprotein(a) concentrations and genetic variants showed no associations with mortality. We conclude that these variables are not useful risk factors to measure to predict progression to death after coronary heart disease is established.

FUNDING

Seventh Framework Programme for Research and Technical Development (AtheroRemo and RiskyCAD), INTERREG IV Oberrhein Programme, Deutsche Nierenstiftung, Else-Kroener Fresenius Foundation, Deutsche Stiftung für Herzforschung, Deutsche Forschungsgemeinschaft, Saarland University, German Federal Ministry of Education and Research, Willy Robert Pitzer Foundation, and Waldburg-Zeil Clinics Isny.

Early inpatient calculation of laboratory-based 30-day readmission risk scores empowers clinical risk modification during index hospitalization

Improving 30-day readmission continues to be problematic for most hospitals. This study reports the creation and validation of sex-specific inpatient (i) heart failure (HF) risk scores using electronic data from the beginning of inpatient care for effective and efficient prediction of 30-day readmission risk.

METHODS

HF patients hospitalized at Intermountain Healthcare from 2005 to 2012 (derivation: n=6079; validation: n=2663) and Baylor Scott & White Health (North Region) from 2005 to 2013 (validation: n=5162) were studied. Sex-specific iHF scores were derived to predict post-hospitalization 30-day readmission using common HF laboratory measures and age. Risk scores adding social, morbidity, and treatment factors were also evaluated.

RESULTS

The iHF model for females utilized potassium, bicarbonate, blood urea nitrogen, red blood cell count, white blood cell count, and mean corpuscular hemoglobin concentration; for males, components were B-type natriuretic peptide, sodium, creatinine, hematocrit, red cell distribution width, and mean platelet volume. Among females, odds ratios (OR) were OR=1.99 for iHF tertile 3 vs. 1 (95% confidence interval [CI]=1.28, 3.08) for Intermountain validation (P-trend across tertiles=0.002) and OR=1.29 (CI=1.01, 1.66) for Baylor patients (P-trend=0.049). Among males, iHF had OR=1.95 (CI=1.33, 2.85) for tertile 3 vs. 1 in Intermountain (P-trend <0.001) and OR=2.03 (CI=1.52, 2.71) in Baylor (P-trend < 0.001). Expanded models using 182-183 variables had predictive abilities similar to iHF.

CONCLUSIONS

Sex-specific laboratory-based electronic health record-delivered iHF risk scores effectively predicted 30-day readmission among HF patients. Efficient to calculate and deliver to clinicians, recent clinical implementation of iHF scores suggest they are useful and useable for more precise clinical HF treatment.

Adverse cardiovascular events in acute coronary syndrome with indications for anticoagulation

OBJECTIVES

Randomized acute coronary syndrome (ACS) trials testing various antithrombotic (AT) regimens have largely excluded patients with coexisting conditions and indications for anticoagulation (AC). The purpose of this study is to examine the 2-year clinical outcomes of patients with ACS with indication for AC due to venous thromboembolism (VTE) during hospitalization for the ACS event or a prior or new diagnosis of atrial fibrillation (AF) with a CHADS2 (Congestive heart failure; Hypertension; Age; Diabetes; previous ischemic Stroke) score ⩾2.

METHODS

ACS patients with AC indication from 2004 to 2009 were identified (n = 619). A Cox proportional hazards model was used to examine the primary efficacy outcome of major adverse cardiovascular events (MACE) including all-cause death, myocardial infarction (MI) or stroke. The primary explanatory variable was at-discharge antithrombotic strategy [single antiplatelet ± AC, dual antiplatelet (DAP) ± AC or AC only; referent DAP + AC].

RESULTS

A total of 261 (42.2%) patients had a MACE event. AT strategy was not a significant factor for MACE (all p > 0.09). The factors associated with MACE were high mortality risk score [hazard ratio (HR)=1.87, 95% confidence interval (CI): 1.39- 2.52; p < 0.001), prior MI (HR = 1.44, 95% CI: 1.03-2.01; p= 0.033) and presentation of ST elevation MI (HR = 2.70, 95% CI: 1.61-4.51; p < 0.001) or non-ST elevation MI (HR = 1.70, 95% CI: 1.15-2.49; p < 0.001) compared with angina.

CONCLUSIONS

In this real world observational study, the at-discharge AT strategy was not significantly associated with the 2-year risk of MACE. These findings do not negate the need for randomized trials to generate evidence-based approaches to management of this important population.

Novel Stratification of Mortality Risk by Kidney Disease Stage

BACKGROUND

Chronic kidney disease (CKD) is a common disorder with a variable clinical course and it is associated with increased mortality. The Intermountain Risk Score (IMRS) is an electronic risk calculator that utilizes complete blood count (CBC) and basic metabolic panel (BMP) values to predict mortality in various healthcare populations. We hypothesized that IMRS would predict mortality in patients with CKD even with adjustment for serum phosphate and urinary albumin.

METHODS

Three thousand eight hundred seventy-two patients with CKD classes IIIA-V had IMRS calculated retrospectively and survival analysis was performed investigating 1- and 5-year mortality. Kaplan-Meier survival curves were generated for predefined IMRS groups of low, medium and high risk for CKD patients overall and by sex and CKD stage. Serum phosphate and urinary albumin/creatinine ratios were modeled in multivariate Cox-proportional hazard models. Receiver operator characteristic curves were used to determine c-statistics for mortality.

RESULTS

For all patients with CKD, mortality was significantly greater for those with medium- or high-risk compared to low-risk IMRS categories, among each CKD stage. Overall, IMRS was predictive of mortality at both 1 and 5 years, even when adjusted for CKD stage and predicted mortality more accurately than CKD stage alone. Albuminuria was not independently associated with mortality and serum phosphate weakly predicted mortality.

CONCLUSION

IMRS is a strong predictor of mortality in patients with CKD and is robustly complementary to CKD stage in refining risk prediction. Given the universal availability and low cost of the CBC and BMP, IMRS may be of a substantial value in CKD risk assessment and management.

MARCKS regulates growth and radiation sensitivity and is a novel prognostic factor for glioma

PURPOSE

This study assessed whether myristoylated alanine-rich C-kinase substrate (MARCKS) can regulate glioblastoma multiforme (GBM) growth, radiation sensitivity, and clinical outcome.

EXPERIMENTAL DESIGN

MARCKS protein levels were analyzed in five GBM explant cell lines and eight patient-derived xenograft tumors by immunoblot, and these levels were correlated to proliferation rates and intracranial growth rates, respectively. Manipulation of MARCKS protein levels was assessed by lentiviral-mediated short hairpin RNA knockdown in the U251 cell line and MARCKS overexpression in the U87 cell line. The effect of manipulation of MARCKS on proliferation, radiation sensitivity, and senescence was assessed. MARCKS gene expression was correlated with survival outcomes in the Repository of Molecular Brain Neoplasia Data (REMBRANDT) Database and The Cancer Genome Atlas (TCGA).

RESULTS

MARCKS protein expression was inversely correlated with GBM proliferation and intracranial xenograft growth rates. Genetic silencing of MARCKS promoted GBM proliferation and radiation resistance, whereas MARCKS overexpression greatly reduced GBM growth potential and induced senescence. We found MARCKS gene expression to be directly correlated with survival in both the REMBRANDT and TCGA databases. Specifically, patients with high MARCKS expressing tumors of the proneural molecular subtype had significantly increased survival rates. This effect was most pronounced in tumors with unmethylated O(6)-methylguanine DNA methyltransferase (MGMT) promoters, a traditionally poor prognostic factor.

CONCLUSIONS

MARCKS levels impact GBM growth and radiation sensitivity. High MARCKS expressing GBM tumors are associated with improved survival, particularly with unmethylated MGMT promoters. These findings suggest the use of MARCKS as a novel target and biomarker for prognosis in the proneural subtype of GBM.

Randomized controlled trial of chewing gum for weight loss

The possible effects on body weight of chewing gum on a regular schedule have not been tested in a randomized controlled trial (RCT). We conducted an 8-week RCT in 201 overweight and obese adults to test the hypothesis that receiving printed material on good nutrition and chewing gum for a minimum of 90 min/day (n = 102) would lead to greater weight loss than receiving printed nutrition information only (n = 99). Changes in BMI, waist circumference, and blood pressure were secondary outcomes. Adherence to the gum-chewing protocol in the intervention group was >95%. In the intention-to-treat analysis, there were virtually no changes in weight or BMI in either group between baseline and the end of the intervention at 8 weeks. Waist circumference decreased significantly in the intervention group between baseline and 8 weeks (mean ± SD change = -1.4 ± 5.3 cm; P = 0.0128); however, there was no significant difference in change in waist circumference comparing the groups. Similarly, systolic and diastolic blood pressure decreased significantly in the intervention group between baseline and 8 weeks (-3.0 ± 9.9 mm Hg; P = 0.0032 and -3.2 ± 7.3 mm Hg; P = 0.0001, respectively); however, there were no significant differences in the changes in systolic or diastolic blood pressure between the groups. Analyses including completers only produced essentially the same results. We conclude that chewing gum on a regular schedule for 8 weeks did not facilitate weight loss in these overweight and obese adults.