Growth differentiation factor 15 and cardiovascular risk: individual patient meta-analysis.

AIMS: Levels of growth differentiation factor 15 (GDF-15), a cytokine secreted in response to cellular stress and inflammation, have been associated with multiple types of cardiovascular (CV) events. However, its comparative prognostic performance across different presentations of atherosclerotic cardiovascular disease (ASCVD) remains unknown. METHODS AND RESULTS: An individual patient meta-analysis was performed using data pooled from eight trials including 53 486 patients. Baseline GDF-15 concentration was analyzed as a continuous variable and using established cutpoints (<1200 ng/L, 1200-1800 ng/L, > 1800 ng/L) to evaluate its prognostic performance for CV death/hospitalization for heart failure (HHF), major adverse cardiovascular events (MACE), and their components using Cox models adjusted for clinical variables and established CV biomarkers. Analyses were further stratified on ASCVD status: acute coronary syndrome (ACS), stabilized after recent ACS, and stable ASCVD. Overall, higher GDF-15 concentration was significantly and independently associated with an increased rate of CV death/HHF and MACE (P < 0.001 for each). However, while GDF-15 showed a robust and consistent independent association with CV death and HHF across all presentations of ASCVD, its prognostic association with future myocardial infarction (MI) and stroke only remained significant in patients stabilized after recent ACS or with stable ASCVD [hazard ratio (HR): 1.24, 95% confidence interval (CI): 1.17-1.31 and HR: 1.16, 95% CI: 1.05-1.28 for MI and stroke, respectively] and not in ACS (HR: 0.98, 95% CI: 0.90-1.06 and HR: 0.87, 95% CI: 0.39-1.92, respectively). CONCLUSION: Growth differentiation factor 15 consistently adds prognostic information for CV death and HHF across the spectrum of ASCVD. GDF-15 also adds prognostic information for MI and stroke beyond clinical risk factors and cardiac biomarkers but not in the setting of ACS.

Effects of Randomized Treatment With Icosapent Ethyl and a Mineral Oil Comparator on Interleukin-1ß, Interleukin-6, C-Reactive Protein, Oxidized Low-Density Lipoprotein Cholesterol, Homocysteine, Lipoprotein(a), and Lipoprotein-Associated Phospholipase A2: A REDUCE-IT Biomarker Substudy.

BACKGROUND: REDUCE-IT (Reduction of Cardiovascular Events With Icosapent Ethyl-Intervention Trial) reported a 25% relative risk reduction in major adverse cardiovascular events with use of icosapent ethyl compared with pharmaceutical grade mineral oil. The mechanisms underlying this benefit remain uncertain. We explored whether treatment allocation in REDUCE-IT might affect a series of biomarkers in pathways known to associate with atherosclerosis risk. METHODS: Serum levels of interleukin-1ß, interleukin-6, high-sensitivity C-reactive protein, oxidized low-density lipoprotein cholesterol, homocysteine, lipoprotein(a), and lipoprotein-associated phospholipase A2 (Lp-PLA2) were measured at baseline, at 12 months, at 24 months, and at the end-of-study visit among REDUCE-IT participants with triglyceride levels ≥135 mg/dL and <500 mg/dL who were randomly allocated to treatment with either 4 grams daily of icosapent ethyl or mineral oil used as a comparator. RESULTS: At baseline, median levels of each biomarker were similar in the 2 treatment groups. The levels of biomarkers associated with atherosclerosis increased over time among those allocated to mineral oil treatment; in this group at 12 months, the median percent increases from baseline were 1.5% for homocysteine, 2.2% for lipoprotein(a), 10.9% for oxidized low-density lipoprotein cholesterol, 16.2% for interleukin-6, 18.5% for lipoprotein-associated phospholipase A2, 21.9% for high-sensitivity C-reactive protein, and 28.9% for interleukin-1ß (all P values <0.001), with similar changes at 24 months. In the icosapent ethyl group, there were minimal changes in these biomarkers at 12 and 24 months. As such, at study conclusion, between-group treatment differences largely reflected increases in the mineral oil group with median percent differences of 2.4% for lipoprotein(a), 3.0% for homocysteine, 4.2% for oxidized low-density lipoprotein cholesterol, 19.8% for interleukin-6, 26.2% for Lp-PLA2, 38.5% for high-sensitivity C-reactive protein, and 48.7% for interleukin-1ß (all P values ≤0.007). These data are consistent with previous REDUCE-IT results in which the median percent change for low-density lipoprotein cholesterol at 12 months was -1.2% among those allocated to icosapent ethyl and 10.9% among those allocated to the mineral oil comparator. CONCLUSIONS: Among participants in REDUCE-IT, allocation to icosapent ethyl had minimal effects on a series of biomarkers associated with atherosclerotic disease, whereas levels increased among those allocated to mineral oil. The effect of these findings on interpretation of the overall risk reductions in clinical events observed within REDUCE-IT is uncertain. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01492361.

Comparison of interleukin-6, C-reactive protein, and low-density lipoprotein cholesterol as biomarkers of residual risk in contemporary practice: secondary analyses from the Cardiovascular Inflammation Reduction Trial.

AIMS: In epidemiologic cohorts initiated >30 years ago, inflammatory biomarkers, such as interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hsCRP) were shown to independently predict future cardiovascular events with a magnitude of effect comparable to that of low-density lipoprotein cholesterol (LDLC). Whether aggressive contemporary therapy for atherosclerosis has altered these relationships is unknown yet has major implications for future drug development. METHODS AND RESULTS: Interleukin-6, hsCRP, and LDLC were measured at baseline in up to 4168 North American patients enrolled in the contemporary Cardiovascular Inflammation Reduction Trial with prior myocardial infarction or multivessel coronary disease who additionally had diabetes or metabolic syndrome and were followed for a period of up to 5 years for incident major recurrent cardiovascular events and all-cause mortality. Three-quarters of the cohort were previously revascularized and the great majority was taking statins, angiotensin blocking agents, beta-blockers, and antithrombotic agents. Participants were randomly allocated to low-dose methotrexate 15 mg weekly or to placebo. Randomized use of methotrexate had no effect on event rates nor plasma levels of IL-6, hsCRP, or LDL over time. Yet, baseline levels of IL-6, hsCRP, and LDLC were all predictors of major recurrent cardiovascular events; adjusted hazard ratios [HR; 95% confidence interval (CI)] for the lowest to highest baseline quartiles of IL-6 were 1.0 (referent), 1.66 (1.18-2.35), 1.92 (1.36-2.70), and 2.11 (1.49-2.99; P < 0.0001), while adjusted HRs for increasing quartiles of hsCRP were 1.0 (referent), 1.28 (0.92-1.79), 1.73 (1.25-2.38), and 1.79 (1.28-2.50; P < 0.0001) and adjusted HRs for increasing quartiles of LDLC were 1.0 (referent), 1.12 (0.78-1.62), 1.25 (0.87-1.79), and 2.38 (1.72-3.30; P < 0.0001). Effect estimates were not statistically different in these analyses for comparisons between IL-6, hsCRP, or LDLC, although IL-6 was the strongest predictor of all-cause mortality. The highest absolute risks were observed among those with elevated levels of both cholesterol and inflammation [HR 6.4 (95% CI 2.9-14.1) for those in the top quartiles of baseline IL-6 and LDLC, HR 4.9 (95% CI 2.6-9.4) for those in the top quartiles of baseline hsCRP and LDLC, both P < 0.0001]. CONCLUSION: Despite aggressive contemporary secondary prevention efforts, the relationships between inflammation, cholesterol, and cardiovascular risk are largely unchanged from those described two decades ago. These data are consistent with the hypothesis that future treatments for atherosclerosis may require a combination of inflammation inhibition and additional cholesterol reduction. CLINICAL TRIAL: ClinicalTrials.gov NCT01594333.

Quantifying atherogenic lipoproteins for lipid-lowering strategies: consensus-based recommendations from EAS and EFLM.

The joint consensus panel of the European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) recently addressed present and future challenges in the laboratory diagnostics of atherogenic lipoproteins. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDLC), LDL cholesterol (LDLC), and calculated non-HDLC (=total - HDLC) constitute the primary lipid panel for estimating risk of atherosclerotic cardiovascular disease (ASCVD) and can be measured in the nonfasting state. LDLC is the primary target of lipid-lowering therapies. For on-treatment follow-up, LDLC shall be measured or calculated by the same method to attenuate errors in treatment decisions due to marked between-method variations. Lipoprotein(a) [Lp(a)]-cholesterol is part of measured or calculated LDLC and should be estimated at least once in all patients at risk of ASCVD, especially in those whose LDLC declines poorly upon statin treatment. Residual risk of ASCVD even under optimal LDL-lowering treatment should be also assessed by non-HDLC or apolipoprotein B (apoB), especially in patients with mild-to-moderate hypertriglyceridemia (2-10 mmol/L). Non-HDLC includes the assessment of remnant lipoprotein cholesterol and shall be reported in all standard lipid panels. Additional apoB measurement can detect elevated LDL particle (LDLP) numbers often unidentified on the basis of LDLC alone. Reference intervals of lipids, lipoproteins, and apolipoproteins are reported for European men and women aged 20-100 years. However, laboratories shall flag abnormal lipid values with reference to therapeutic decision thresholds.

Quantifying Atherogenic Lipoproteins: Current and Future Challenges in the Era of Personalized Medicine and Very Low Concentrations of LDL Cholesterol. A Consensus Statement from EAS and EFLM.

BACKGROUND: The European Atherosclerosis Society-European Federation of Clinical Chemistry and Laboratory Medicine Consensus Panel aims to provide recommendations to optimize atherogenic lipoprotein quantification for cardiovascular risk management. CONTENT: We critically examined LDL cholesterol, non-HDL cholesterol, apolipoprotein B (apoB), and LDL particle number assays based on key criteria for medical application of biomarkers. (a) Analytical performance: Discordant LDL cholesterol quantification occurs when LDL cholesterol is measured or calculated with different assays, especially in patients with hypertriglyceridemia >175 mg/dL (2 mmol/L) and low LDL cholesterol concentrations <70 mg/dL (1.8 mmol/L). Increased lipoprotein(a) should be excluded in patients not achieving LDL cholesterol goals with treatment. Non-HDL cholesterol includes the atherogenic risk component of remnant cholesterol and can be calculated in a standard nonfasting lipid panel without additional expense. ApoB more accurately reflects LDL particle number. (b) Clinical performance: LDL cholesterol, non-HDL cholesterol, and apoB are comparable predictors of cardiovascular events in prospective population studies and clinical trials; however, discordance analysis of the markers improves risk prediction by adding remnant cholesterol (included in non-HDL cholesterol) and LDL particle number (with apoB) risk components to LDL cholesterol testing. (c) Clinical and cost-effectiveness: There is no consistent evidence yet that non-HDL cholesterol-, apoB-, or LDL particle-targeted treatment reduces the number of cardiovascular events and healthcare-related costs than treatment targeted to LDL cholesterol. SUMMARY: Follow-up of pre- and on-treatment (measured or calculated) LDL cholesterol concentration in a patient should ideally be performed with the same documented test method. Non-HDL cholesterol (or apoB) should be the secondary treatment target in patients with mild to moderate hypertriglyceridemia, in whom LDL cholesterol measurement or calculation is less accurate and often less predictive of cardiovascular risk. Laboratories should report non-HDL cholesterol in all standard lipid panels.

Insight into infection-mediated prostate damage: Contrasting patterns of C-reactive protein and prostate-specific antigen levels during infection.

BACKGROUND: To investigate mechanisms underlying our previous observation of a large rise in serum prostate-specific antigen, a marker of prostate pathology, during both sexually transmitted and systemic infections, we measured serum high-sensitivity C-reactive protein (hsCRP), a marker of systemic inflammation, in our previous case-control study of young, male US military members and compared our findings to those for PSA. METHODS: We measured hsCRP before and during infection for 299 chlamydia, 112 gonorrhea, and 59 non-chlamydial, non-gonococcal urethritis (NCNGU) cases; before and after infection for 55 infectious mononucleosis (IM) and 90 other systemic/non-genitourinary cases; and for 220-256 controls. RESULTS: Only gonorrhea cases were significantly more likely to have a large hsCRP rise (≥1.40 mg/L or ≥239%) during infection than controls (P < 0.01). However, gonorrhea, IM, and other systemic/non-genitourinary cases were more likely to have a rise of any magnitude up to one year post-diagnosis than controls (p = 0.038-0.077). CONCLUSIONS: These findings, which differ from those for PSA, suggest distinct mechanisms of elevation for hsCRP and PSA, and support both direct (eg, prostate infection) and indirect (eg, systemic inflammation-mediated prostate cell damage) mechanisms for PSA elevation. Future studies should explore our PSA findings further for their relevance to both prostate cancer screening and risk.

Plasma proprotein convertase subtilisin/kexin type 9 levels and the risk of first cardiovascular events.

AIMS: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that enhances degradation of the LDL receptor. While agents that inhibit PCSK9 markedly reduce atherogenic lipoproteins and show great promise for event reduction, it is unknown whether plasma PCSK9 levels predict incident cardiovascular events. METHODS AND RESULTS: In a nested case-control evaluation conducted in a prospective cohort of >28 000 initially healthy American women, we measured plasma concentrations of PCSK9 at baseline among 358 participants who subsequently developed major cardiovascular events (cases) and among 358 age, smoking, and hormone replacement therapy matched participants who remained free of disease during 17 years of follow-up (controls). Proprotein convertase subtilisin/kexin type 9 level was not significantly related to smoking status, hypertension, obesity, or a family history of premature cardiovascular disease but was positively associated with apolipoprotein B-100 (r = 0.20, P< 0.001), and triglycerides (r = 0.13, P = 0.004). No associations were observed between PCSK9 and apo A1, HDLC, lipoprotein(a), or high-sensitivity C-reactive protein. Despite modest positive association with atherogenic lipids, baseline levels of PCSK9 did not predict the first cardiovascular events; the odds ratios (ORs) for future vascular events for the lowest (referent) to highest baseline quartiles of PCSK9 were 1.0, 0.94, 0.98, and 1.15 (P-trend = 0.53). In contrast, the corresponding ORs for baseline apo B levels were 1.0, 1.14, 1.34, and 1.94 (P-trend = 0.002). CONCLUSIONS: In a large-scale primary prevention cohort, plasma levels of PCSK9 measured at baseline did not predict future cardiovascular events.

Fasting is not routinely required for determination of a lipid profile: clinical and laboratory implications including flagging at desirable concentration cut-points-a joint consensus statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine.

AIMS: To critically evaluate the clinical implications of the use of non-fasting rather than fasting lipid profiles and to provide guidance for the laboratory reporting of abnormal non-fasting or fasting lipid profiles. METHODS AND RESULTS: Extensive observational data, in which random non-fasting lipid profiles have been compared with those determined under fasting conditions, indicate that the maximal mean changes at 1-6 h after habitual meals are not clinically significant [+0.3 mmol/L (26 mg/dL) for triglycerides; -0.2 mmol/L (8 mg/dL) for total cholesterol; -0.2 mmol/L (8 mg/dL) for LDL cholesterol; +0.2 mmol/L (8 mg/dL) for calculated remnant cholesterol; -0.2 mmol/L (8 mg/dL) for calculated non-HDL cholesterol]; concentrations of HDL cholesterol, apolipoprotein A1, apolipoprotein B, and lipoprotein(a) are not affected by fasting/non-fasting status. In addition, non-fasting and fasting concentrations vary similarly over time and are comparable in the prediction of cardiovascular disease. To improve patient compliance with lipid testing, we therefore recommend the routine use of non-fasting lipid profiles, while fasting sampling may be considered when non-fasting triglycerides >5 mmol/L (440 mg/dL). For non-fasting samples, laboratory reports should flag abnormal concentrations as triglycerides ≥2 mmol/L (175 mg/dL), total cholesterol ≥5 mmol/L (190 mg/dL), LDL cholesterol ≥3 mmol/L (115 mg/dL), calculated remnant cholesterol ≥0.9 mmol/L (35 mg/dL), calculated non-HDL cholesterol ≥3.9 mmol/L (150 mg/dL), HDL cholesterol ≤1 mmol/L (40 mg/dL), apolipoprotein A1 ≤1.25 g/L (125 mg/dL), apolipoprotein B ≥1.0 g/L (100 mg/dL), and lipoprotein(a) ≥50 mg/dL (80th percentile); for fasting samples, abnormal concentrations correspond to triglycerides ≥1.7 mmol/L (150 mg/dL). Life-threatening concentrations require separate referral when triglycerides >10 mmol/L (880 mg/dL) for the risk of pancreatitis, LDL cholesterol >13 mmol/L (500 mg/dL) for homozygous familial hypercholesterolaemia, LDL cholesterol >5 mmol/L (190 mg/dL) for heterozygous familial hypercholesterolaemia, and lipoprotein(a) >150 mg/dL (99th percentile) for very high cardiovascular risk. CONCLUSION: We recommend that non-fasting blood samples be routinely used for the assessment of plasma lipid profiles. Laboratory reports should flag abnormal values on the basis of desirable concentration cut-points. Non-fasting and fasting measurements should be complementary but not mutually exclusive.

Fasting Is Not Routinely Required for Determination of a Lipid Profile: Clinical and Laboratory Implications Including Flagging at Desirable Concentration Cutpoints-A Joint Consensus Statement from the European Atherosclerosis Society and European Federation of Clinical Chemistry and Laboratory Medicine.

AIMS: To critically evaluate the clinical implications of the use of non-fasting rather than fasting lipid profiles and to provide guidance for the laboratory reporting of abnormal non-fasting or fasting lipid profiles. METHODS AND RESULTS: Extensive observational data, in which random non-fasting lipid profiles have been compared with those determined under fasting conditions, indicate that the maximal mean changes at 1-6 h after habitual meals are not clinically significant [+0.3 mmol/L (26 mg/dL) for triglycerides; -0.2 mmol/L (8 mg/dL) for total cholesterol; -0.2 mmol/L (8 mg/dL) for LDL cholesterol; +0.2 mmol/L (8 mg/dL) for calculated remnant cholesterol; -0.2 mmol/L (8 mg/dL) for calculated non-HDL cholesterol]; concentrations of HDL cholesterol, apolipoprotein A1, apolipoprotein B, and lipoprotein(a) are not affected by fasting/non-fasting status. In addition, non-fasting and fasting concentrations vary similarly over time and are comparable in the prediction of cardiovascular disease. To improve patient compliance with lipid testing, we therefore recommend the routine use of non-fasting lipid profiles, whereas fasting sampling may be considered when non-fasting triglycerides are >5 mmol/L (440 mg/dL). For non-fasting samples, laboratory reports should flag abnormal concentrations as triglycerides ≥2 mmol/L (175 mg/dL), total cholesterol ≥5 mmol/L (190 mg/dL), LDL cholesterol ≥3 mmol/L (115 mg/dL), calculated remnant cholesterol ≥0.9 mmol/L (35 mg/dL), calculated non-HDL cholesterol ≥3.9 mmol/L (150 mg/dL), HDL cholesterol ≤1 mmol/L (40 mg/dL), apolipoprotein A1 ≤1.25 g/L (125 mg/dL), apolipoprotein B ≥1.0 g/L (100 mg/dL), and lipoprotein(a) ≥50 mg/dL (80th percentile); for fasting samples, abnormal concentrations correspond to triglycerides ≥1.7 mmol/L (150 mg/dL). Life-threatening concentrations require separate referral for the risk of pancreatitis when triglycerides are >10 mmol/L (880 mg/dL), for homozygous familial hypercholesterolemia when LDL cholesterol is >13 mmol/L (500 mg/dL), for heterozygous familial hypercholesterolemia when LDL cholesterol is >5 mmol/L (190 mg/dL), and for very high cardiovascular risk when lipoprotein(a) >150 mg/dL (99th percentile). CONCLUSIONS: We recommend that non-fasting blood samples be routinely used for the assessment of plasma lipid profiles. Laboratory reports should flag abnormal values on the basis of desirable concentration cutpoints. Non-fasting and fasting measurements should be complementary but not mutually exclusive.

Association between serum 25-hydroxyvitamin D and serum sex steroid hormones among men in NHANES.

BACKGROUND: Recent literature suggests that high circulating vitamin D may increase prostate cancer risk. Although the mechanism through which vitamin D may increase risk is unknown, vitamin D concentration could influence circulating sex steroid hormones that may be associated with prostate cancer; an alternate explanation is that it could be associated with prostate-specific antigen (PSA) concentration causing detection bias. OBJECTIVE: We examined whether serum vitamin D concentration was associated with sex steroid hormone and PSA concentrations in a cross-sectional analysis of men in the National Health and Nutrition Examination Surveys (NHANES). DESIGN: Testosterone, oestradiol, sex hormone-binding globulin (SHBG), androstanediol glucuronide, and 25-hydroxyvitamin D (25(OH)D) were measured in serum from men aged 20 and older participating in NHANES III (n = 1315) and NHANES 2001-2004 (n = 318). Hormone concentrations were compared across 25(OH)D quintiles, adjusting for age, race/ethnicity, body fat percentage, and smoking. PSA concentration was estimated by 25(OH)D quintile in 4013 men from NHANES 2001-2006. RESULTS: In NHANES III, higher testosterone (quintile (Q) 1 = 17·2, 95% confidence interval (CI) = 16·1-18·6; Q5 = 19·6, 95% CI = 18·7-20·6 nmol/l, P-trend = 0·0002) and SHBG (Q1 = 33·8, 95% CI = 30·8-37·0; Q5 = 38·4, 95% CI = 35·8-41·2 nmol/l, P-trend = 0·0005) were observed with increasing 25(OH)D. Similar results were observed in NHANES 2001-2004. PSA concentration was not associated with serum 25(OH)D (P-trend = 0·34). CONCLUSION: Results from these nationally representative studies support a positive association between serum 25(OH)D and testosterone and SHBG. The findings support an indirect mechanism through which vitamin D may increase prostate cancer risk, and suggest the link to prostate cancer is not due to PSA-detection bias.

An Increase in Dietary Quality Is Associated with Favorable Plasma Biomarkers of the Brain-Adipose Axis in Apparently Healthy US Women.

BACKGROUND: The associations between long-term dietary quality and biomarkers of the brain-adipose axis have not been examined. OBJECTIVE: We evaluated both cross-sectional and longitudinal associations between dietary quality and several biomarkers involved in the brain-adipose axis. METHODS: In the Nurses' Health Study II, 831 women [baseline mean age: 45 y; body mass index (BMI; in kg/m(2)): 24.6] were randomly selected from women who provided 2 fasting blood samples in 1996-1999 and 2010-2011 to measure plasma concentrations of leptin, soluble leptin receptor (sOB-R), adiponectin, insulin, retinol binding protein-4 (RBP-4), interleukin-6 (IL-6), and C-reactive protein (CRP). Dietary quality was assessed by the Alternative Healthy Eating Index (AHEI-2010) with the use of semiquantitative food-frequency questionnaires administered in 1995 and 2011. We used linear mixed models to evaluate the cross-sectional associations between dietary quality and biomarker concentrations. We also examined change in dietary quality in relation to change in biomarker concentrations. RESULTS: In cross-sectional analyses that compared the highest with the lowest quintile of AHEI-2010, we observed significantly lower leptin (P-trend < 0.0001), insulin (P-trend < 0.0001), and CRP (P-trend = 0.02) and significantly higher sOB-R (P-trend < 0.0001) and adiponectin (P-trend = 0.0003). These associations, except for CRP, remained significant after adjustment for BMI. In longitudinal analyses, women in the highest quintile of AHEI-2010 score change (most improvement) had a 13% increase in leptin, compared with a 42% increase (P-trend < 0.0001) in the lowest quintile (least improvement). The corresponding multivariable-adjusted percentage changes for other biomarkers were 4% compared with -1% for sOB-R (P-trend = 0.04), 14% compared with 6% for adiponectin (P-trend = 0.02), and -11% compared with 16% for CRP (P-trend = 0.02). Adjustment for interim weight change attenuated these associations. No associations were observed for RBP-4 or IL-6. CONCLUSION: Improvement in dietary quality was associated with favorable profiles of several biomarkers of the brain-adipose axis in women.

Targeted peptide measurements in biology and medicine: best practices for mass spectrometry-based assay development using a fit-for-purpose approach.

Adoption of targeted mass spectrometry (MS) approaches such as multiple reaction monitoring (MRM) to study biological and biomedical questions is well underway in the proteomics community. Successful application depends on the ability to generate reliable assays that uniquely and confidently identify target peptides in a sample. Unfortunately, there is a wide range of criteria being applied to say that an assay has been successfully developed. There is no consensus on what criteria are acceptable and little understanding of the impact of variable criteria on the quality of the results generated. Publications describing targeted MS assays for peptides frequently do not contain sufficient information for readers to establish confidence that the tests work as intended or to be able to apply the tests described in their own labs. Guidance must be developed so that targeted MS assays with established performance can be made widely distributed and applied by many labs worldwide. To begin to address the problems and their solutions, a workshop was held at the National Institutes of Health with representatives from the multiple communities developing and employing targeted MS assays. Participants discussed the analytical goals of their experiments and the experimental evidence needed to establish that the assays they develop work as intended and are achieving the required levels of performance. Using this "fit-for-purpose" approach, the group defined three tiers of assays distinguished by their performance and extent of analytical characterization. Computational and statistical tools useful for the analysis of targeted MS results were described. Participants also detailed the information that authors need to provide in their manuscripts to enable reviewers and readers to clearly understand what procedures were performed and to evaluate the reliability of the peptide or protein quantification measurements reported. This paper presents a summary of the meeting and recommendations.

STARD 2015: An Updated List of Essential Items for Reporting Diagnostic Accuracy Studies.

Incomplete reporting has been identified as a major source of avoidable waste in biomedical research. Essential information is often not provided in study reports, impeding the identification, critical appraisal, and replication of studies. To improve the quality of reporting of diagnostic accuracy studies, the Standards for Reporting of Diagnostic Accuracy Studies (STARD) statement was developed. Here we present STARD 2015, an updated list of 30 essential items that should be included in every report of a diagnostic accuracy study. This update incorporates recent evidence about sources of bias and variability in diagnostic accuracy and is intended to facilitate the use of STARD. As such, STARD 2015 may help to improve completeness and transparency in reporting of diagnostic accuracy studies.

Interleukin-6 and risk of colorectal cancer: results from the CLUE II cohort and a meta-analysis of prospective studies.

PURPOSE: The association between prediagnostic interleukin-6 (IL-6) concentrations and risk of colorectal cancer was evaluated in a nested case-control study and a meta-analysis of prospective studies. METHODS: Colorectal cancer cases (n = 173) and matched controls (n = 345) were identified between 1989 and 2000 among participants in the CLUE II cohort of Washington Country, Maryland. Matched odds ratios and the corresponding 95 % confidence intervals (CIs) were estimated using conditional logistic regression models. RESULTS: Participants in the highest third of plasma IL-6 concentration had a 2.48 times higher risk of colon cancer compared to participants in the bottom third (95 % CI 1.26-4.87; p-trend 0.02) after multivariate adjustment. This association did not differ according to the stage of disease, age, sex, or other potential modifying variables and remained statistically significant after adjustment for C-reactive protein concentrations. No statistically significant association was observed for rectal cancer risk. The meta-analysis of six prospective studies yielded an increased but borderline statistically significant risk of colon cancer per 1 U increase in naturally logarithm-transformed IL-6 (summary RR 1.22; 95 % CI 1.00-1.49; I (2) 46 %). An inverse association was noted for rectal cancer (RR 0.69; 95 % CI 0.54-0.88; I (2) 0 %), but there was evidence for small-study effects (p 0.02). CONCLUSION: Our findings provide support for a modest positive association between IL-6 concentrations and colon cancer risk. More work is needed to determine whether IL-6 is a valid marker of colorectal inflammation and whether such inflammation contributes to colon and rectal cancer risk.

STARD 2015: An Updated List of Essential Items for Reporting Diagnostic Accuracy Studies.

Incomplete reporting has been identified as a major source of avoidable waste in biomedical research. Essential information is often not provided in study reports, impeding the identification, critical appraisal, and replication of studies. To improve the quality of reporting of diagnostic accuracy studies, the Standards for Reporting of Diagnostic Accuracy Studies (STARD) statement was developed. Here we present STARD 2015, an updated list of 30 essential items that should be included in every report of a diagnostic accuracy study. This update incorporates recent evidence about sources of bias and variability in diagnostic accuracy and is intended to facilitate the use of STARD. As such, STARD 2015 may help to improve completeness and transparency in reporting of diagnostic accuracy studies.

Association of C-reactive protein, tumor necrosis factor-alpha, and interleukin-6 with chronic kidney disease.

BACKGROUND: We studied the association of inflammatory biomarkers including C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) with chronic kidney disease (CKD). METHODS: We conducted a case-control study among 201 CKD patients and 201 community-based controls in the greater New Orleans area. CKD was defined as estimated-glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) or albuminuria ≥30 mg/24-h. Serum CRP, TNF-α, and IL-6 were measured using standard methods. Multivariable regression models were used to examine associations between the inflammatory biomarkers and CKD adjusting for important CKD risk factors, history of cardiovascular disease, and use of antihypertensive, antidiabetic, and lipid-lowering agents and aspirin. RESULTS: The multivariable-adjusted medians (interquartile-range) were 2.91 (1.47, 5.24) mg/L in patients with CKD vs. 1.91 (0.99, 3.79) mg/L in controls without CKD (p = 0.39 for group difference) for CRP; 1.86 (1.51, 2.63) pg/mL vs. 1.26 (1.01, 1.98) pg/mL (p < 0.0001) for TNF-α; and 2.53 (1.49, 4.42) pg/mL vs. 1.39 (0.95, 2.15) pg/mL (p = 0.04) for IL-6, respectively. Compared to the lowest tertile, the highest tertile of TNF-α (OR 7.1, 95% CI 3.2 to 15.5) and IL-6 (OR 2.5, 95% CI 1.1 to 5.5) were significantly associated with higher odds of CKD in multivariable-adjusted models. Additionally, higher TNF-α and IL-6 were independently and significantly associated with lower eGFR and higher albuminuria. CONCLUSIONS: Our data suggest that TNF-α and IL-6, but not CRP, are associated with the prevalence and severity of CKD, independent from established CKD risk factors, history of cardiovascular disease, and use of antihypertensive, antidiabetic, and lipid-lowering agents and aspirin.

Association between endogenous sex steroid hormones and insulin-like growth factor proteins in US men.

PURPOSE: Sex steroid hormone concentrations and insulin-like growth factor (IGF) proteins have been independently associated with risk of cancer, chronic diseases, and mortality. However, studies that evaluated the inter-relation between the sex hormones and IGF pathways have provided mixed results. We examined the association between endogenous sex hormones and sex hormone-binding globulin (SHBG) with IGF-1 and IGF-binding protein 3 (IGFBP-3) in a population-based sample of US men. METHODS: Data from 1,135 men aged 20 years or older participating in the third National Health and Nutrition Examination Survey (NHANES III) were analyzed. Weighted linear regression was used to estimate geometric means and 95 % confidence intervals for IGF-1 and IGFBP-3 concentrations by sex steroid hormones and SHBG after adjusting for age, race/ethnicity, body mass index, waist circumference, alcohol consumption, cigarette smoking, physical activity, diabetes, and mutually adjusting for other sex hormones and SHBG. RESULTS: No significant association was observed between sex steroid hormones, SHBG, and IGF-1 concentrations. Total estradiol (% difference in Q5 - Q1 geometric means -9.7 %; P-trend 0.05) and SHBG (% difference -7.3 %; P-trend 0.02) were modestly inversely associated with IGFBP-3. Total testosterone was modestly inversely associated with IGFBP-3 (% difference -6.2 %; P-trend 0.01), but this association disappeared after adjustment for total estradiol and SHBG (% difference 2.6 %; P-trend 0.23). Androstanediol glucuronide was not associated with IGFBP-3. CONCLUSIONS: These findings suggest that there may be inter-relationships between circulating total estradiol, SHBG, and IGFBP-3 concentrations. Future research may consider these inter-relationships when evaluating potential joint effects of the sex hormones and IGF pathways.