C-reactive protein concentration and risk of coronary heart disease, stroke, and mortality: an individual participant meta-analysis

BACKGROUND

Associations of C-reactive protein (CRP) concentration with risk of major diseases can best be assessed by long-term prospective follow-up of large numbers of people. We assessed the associations of CRP concentration with risk of vascular and non-vascular outcomes under different circumstances.

METHODS

We meta-analysed individual records of 160 309 people without a history of vascular disease (ie, 1.31 million person-years at risk, 27 769 fatal or non-fatal disease outcomes) from 54 long-term prospective studies. Within-study regression analyses were adjusted for within-person variation in risk factor levels.

RESULTS

Log(e) CRP concentration was linearly associated with several conventional risk factors and inflammatory markers, and nearly log-linearly with the risk of ischaemic vascular disease and non-vascular mortality. Risk ratios (RRs) for coronary heart disease per 1-SD higher log(e) CRP concentration (three-fold higher) were 1.63 (95% CI 1.51-1.76) when initially adjusted for age and sex only, and 1.37 (1.27-1.48) when adjusted further for conventional risk factors; 1.44 (1.32-1.57) and 1.27 (1.15-1.40) for ischaemic stroke; 1.71 (1.53-1.91) and 1.55 (1.37-1.76) for vascular mortality; and 1.55 (1.41-1.69) and 1.54 (1.40-1.68) for non-vascular mortality. RRs were largely unchanged after exclusion of smokers or initial follow-up. After further adjustment for fibrinogen, the corresponding RRs were 1.23 (1.07-1.42) for coronary heart disease; 1.32 (1.18-1.49) for ischaemic stroke; 1.34 (1.18-1.52) for vascular mortality; and 1.34 (1.20-1.50) for non-vascular mortality.

INTERPRETATION

CRP concentration has continuous associations with the risk of coronary heart disease, ischaemic stroke, vascular mortality, and death from several cancers and lung disease that are each of broadly similar size. The relevance of CRP to such a range of disorders is unclear. Associations with ischaemic vascular disease depend considerably on conventional risk factors and other markers of inflammation.

FUNDING

British Heart Foundation, UK Medical Research Council, BUPA Foundation, and GlaxoSmithKline.

Chronic subclinical inflammation as part of the insulin resistance syndrome: the Insulin Resistance Atherosclerosis Study (IRAS)

BACKGROUND

Inflammation has been suggested as a risk factor for the development of atherosclerosis. Recently, some components of the insulin resistance syndrome (IRS) have been related to inflammatory markers. We hypothesized that insulin insensitivity, as directly measured, may be associated with inflammation in nondiabetic subjects.

METHODS AND RESULTS

We studied the relation of C-reactive protein (CRP), fibrinogen, and white cell count to components of IRS in the nondiabetic population of the Insulin Resistance Atherosclerosis Study (IRAS) (n=1008; age, 40 to 69 years; 33% with impaired glucose tolerance), a multicenter, population-based study. None of the subjects had clinical coronary artery disease. Insulin sensitivity (S(I)) was measured by a frequently sampled intravenous glucose tolerance test, and CRP was measured by a highly sensitive competitive immunoassay. All 3 inflammatory markers were correlated with several components of the IRS. Strong associations were found between CRP and measures of body fat (body mass index, waist circumference), S(I), and fasting insulin and proinsulin (all correlation coefficients >0.3, P<0.0001). The associations were consistent among the 3 ethnic groups of the IRAS. There was a linear increase in CRP levels with an increase in the number of metabolic disorders. Body mass index, systolic blood pressure, and S(I) were related to CRP levels in a multivariate linear regression model.

CONCLUSIONS

We suggest that chronic subclinical inflammation is part of IRS. CRP, a predictor of cardiovascular events in previous reports, was independently related to S(I). These findings suggest potential benefits of anti-inflammatory or insulin-sensitizing treatment strategies in healthy individuals with features of IRS.

Haemostatic function and ischaemic heart disease: principal results of the Northwick Park Heart Study

The Northwick Park Heart Study (NPHS) has investigated the thrombotic component of ischaemic heart disease (IHD) by the inclusion of measures of haemostatic function. Among 1511 white men aged between 40 and 64 at the time of recruitment, 109 subsequently experienced first major events of IHD. High levels of factor VII coagulant activity and of plasma fibrinogen were associated with increased risk, especially for events occurring within 5 years of recruitment. These associations seemed to be stronger than for cholesterol, elevations of one standard deviation in factor VII activity, fibrinogen, and cholesterol being associated with increases in the risk of an episode of IHD within 5 years of 62%, 84%, and 43% respectively. Multiple regression analyses indicated independent associations between each of the clotting factor measures and IHD but not between the blood cholesterol level and IHD incidence. The risk of IHD in those with high fibrinogen levels was greater in younger than in older men. Much of the association between smoking and IHD may be mediated through the plasma fibrinogen level. The biochemical disturbance leading to IHD may lie at least as much in the coagulation system as in the metabolism of cholesterol.

Prevalence of and risk factors for peripheral arterial disease in the United States: results from the National Health and Nutrition Examination Survey, 1999-2000

BACKGROUND

Peripheral arterial disease (PAD) is associated with significant morbidity and mortality and is an important marker of subclinical coronary heart disease. However, estimates of PAD prevalence in the general US population have varied widely.

METHODS AND RESULTS

We analyzed data from 2174 participants aged 40 years and older from the 1999-2000 National Health and Nutrition Examination Survey. PAD was defined as an ankle-brachial index <0.90 in either leg. The prevalence of PAD among adults aged 40 years and over in the United States was 4.3% (95% CI 3.1% to 5.5%), which corresponds to approximately 5 million individuals (95% CI 4 to 7 million). Among those aged 70 years or over, the prevalence was 14.5% (95% CI 10.8% to 18.2%). In age- and gender-adjusted logistic regression analyses, black race/ethnicity (OR 2.83, 95% CI 1.48 to 5.42) current smoking (OR 4.46, 95% CI 2.25 to 8.84), diabetes (OR 2.71, 95% CI 1.03 to 7.12), hypertension (OR 1.75, 95% CI 0.97 to 3.13), hypercholesterolemia (OR 1.68, 95% CI 1.09 to 2.57), and low kidney function (OR 2.00, 95% CI 1.08 to 3.70) were positively associated with prevalent PAD. More than 95% of persons with PAD had 1 or more cardiovascular disease risk factors. Elevated fibrinogen and C-reactive protein levels were also associated with PAD.

CONCLUSIONS

This study provides nationally representative prevalence estimates of PAD in the United States, revealing that PAD affects more than 5 million adults. PAD prevalence increases dramatically with age and disproportionately affects blacks. The vast majority of individuals with PAD have 1 or more cardiovascular disease risk factors that should be targeted for therapy.

Strong association between malnutrition, inflammation, and atherosclerosis in chronic renal failure

BACKGROUND

Atherosclerotic cardiovascular disease and malnutrition are widely recognized as leading causes of the increased morbidity and mortality observed in uremic patients. C-reactive protein (CRP), an acute-phase protein, is a predictor of cardiovascular mortality in nonrenal patient populations. In chronic renal failure (CRF), the prevalence of an acute-phase response has been associated with an increased mortality.

METHODS

One hundred and nine predialysis patients (age 52 +/- 1 years) with terminal CRF (glomerular filtration rate 7 +/- 1 ml/min) were studied. By using noninvasive B-mode ultrasonography, the cross-sectional carotid intima-media area was calculated, and the presence or absence of carotid plaques was determined. Nutritional status was assessed by subjective global assessment (SGA), dual-energy x-ray absorptiometry (DXA), serum albumin, serum creatinine, serum urea, and 24-hour urine urea excretion. The presence of an inflammatory reaction was assessed by CRP, fibrinogen (N = 46), and tumor necrosis factor-alpha (TNF-alpha; N = 87). Lipid parameters, including Lp(a) and apo(a)-isoforms, as well as markers of oxidative stress (autoantibodies against oxidized low-density lipoprotein and vitamin E), were also determined.

RESULTS

Compared with healthy controls, CRF patients had an increased mean carotid intima-media area (18.3 +/- 0.6 vs. 13.2 +/- 0.7 mm2, P < 0.0001) and a higher prevalence of carotid plaques (72 vs. 32%, P = 0.001). The prevalence of malnutrition (SGA 2 to 4) was 44%, and 32% of all patients had an acute-phase response (CRP > or = 10 mg/liter). Malnourished patients had higher CRP levels (23 +/- 3 vs. 13 +/- 2 mg/liter, P < 0.01), elevated calculated intima-media area (20.2 +/- 0.8 vs. 16.9 +/- 0.7 mm2, P < 0.01) and a higher prevalence of carotid plaques (90 vs. 60%, P < 0.0001) compared with well-nourished patients. During stepwise multivariate analysis adjusting for age and gender, vitamin E (P < 0.05) and CRP (P < 0.05) remained associated with an increased intima-media area. The presence of carotid plaques was significantly associated with age (P < 0.001), log oxidized low-density lipoprotein (oxLDL; P < 0.01), and small apo(a) isoform size (P < 0.05) in a multivariate logistic regression model.

CONCLUSION

These results indicate that the rapidly developing atherosclerosis in advanced CRF appears to be caused by a synergism of different mechanisms, such as malnutrition, inflammation, oxidative stress, and genetic components. Apart from classic risk factors, low vitamin E levels and elevated CRP levels are associated with an increased intima-media area, whereas small molecular weight apo(a) isoforms and increased levels of oxLDL are associated with the presence of carotid plaques.

Association between chronic obstructive pulmonary disease and systemic inflammation: a systematic review and a meta-analysis

BACKGROUND

Individuals with chronic obstructive pulmonary disease (COPD) are at increased risk of cardiovascular diseases, osteoporosis, and muscle wasting. Systemic inflammation may be involved in the pathogenesis of these disorders. A study was undertaken to determine whether systemic inflammation is present in stable COPD.

METHODS

A systematic review was conducted of studies which reported on the relationship between COPD, forced expiratory volume in 1 second (FEV(1)) or forced vital capacity (FVC), and levels of various systemic inflammatory markers: C-reactive protein (CRP), fibrinogen, leucocytes, tumour necrosis factor-alpha (TNF-alpha), and interleukins 6 and 8. Where possible the results were pooled together to produce a summary estimate using a random or fixed effects model.

RESULTS

Fourteen original studies were identified. Overall, the standardised mean difference in the CRP level between COPD and control subjects was 0.53 units (95% confidence interval (CI) 0.34 to 0.72). The standardised mean difference in the fibrinogen level was 0.47 units (95% CI 0.29 to 0.65). Circulating leucocytes were also higher in COPD than in control subjects (standardised mean difference 0.44 units (95% CI 0.20 to 0.67)), as were serum TNF-alpha levels (standardised mean difference 0.59 units (95% CI 0.29 to 0.89)).

CONCLUSIONS

Reduced lung function is associated with increased levels of systemic inflammatory markers which may have important pathophysiological and therapeutic implications for subjects with stable COPD.

Fibrinogen as a risk factor for stroke and myocardial infarction

To study the possible risk factors for cardiovascular disease, we collected data on plasma levels of coagulation factors, blood pressure, serum cholesterol, and smoking in a random sample of 792 men 54 years of age. During 13.5 years of follow-up, myocardial infarction occurred in 92 men, stroke in 37, and death from causes other than myocardial infarction or stroke in 60. The blood pressure, degree of smoking, serum cholesterol, and fibrinogen level measured at the base-line examination proved to be significant risk factors for infarction by univariate analyses during follow-up, and blood pressure and fibrinogen were risk factors for stroke. Fibrinogen and smoking were strongly related to each other. The relation between fibrinogen and infarction, and between fibrinogen and stroke, became weaker when blood pressure, serum cholesterol, and smoking habits were taken into account, but was still significant for stroke. Although causality cannot be inferred from these data, it is possible that the fibrinogen level plays an important part in the development of stroke and myocardial infarction.

Inflammation enhances cardiovascular risk and mortality in hemodialysis patients

BACKGROUND

Atherosclerosis, a major problem in patients on chronic hemodialysis, has been characterized as an inflammatory disease. C-reactive protein (CRP), the prototypical acute phase protein in humans, is a predictor of cardiovascular mortality in the general population. We hypothesize that several of the classic, as well as nontraditional, cardiovascular risk factors may respond to acute phase reactions. An activated acute phase response may influence or predict cardiovascular risk.

METHODS

In 280 stable hemodialysis patients, serum lipids, apolipoproteins (apo) A-I and B, lipoprotein(a) [Lp(a)], fibrinogen, and serum albumin (Salb) were determined in relation to CRP and serum amyloid A (SAA), two sensitive markers of an acute phase response. Mortality was monitored prospectively over a two year period.

RESULTS

Serum CRP and SAA were found to be elevated (more than 8 and more than 10 mg/liter, respectively) in 46% and 47% of the patients in the absence of clinically apparent infection. Patients with elevated CRP or SAA had significantly higher serum levels of Lp(a), higher plasma fibrinogen, and lower serum levels of high-density lipoprotein cholesterol, apo A-I, and Salb than patients with normal CRP or SAA. The rise in Lp(a) concentration was restricted to patients exhibiting high molecular weight apo(a) isoforms. During follow-up, 72 patients (25.7%) had died, mostly due to cardiovascular events (58%). Overall mortality and cardiovascular mortality were significantly higher in patients with elevated CRP (31% vs. 16%, P < 0.0001, and 23% vs. 5%, P < 0.0001, respectively) or SAA (29% vs. 19%, P = 0.004, and 20 vs. 10%, P = 0.008, respectively) and were also higher in patients with Salb of lower than 40 g/liter (44% vs. 14%, P < 0.0001, and 34% vs. 6%, P < 0.0001, respectively). Univariate Cox regression analysis demonstrated that age, diabetes, pre-existing cardiovascular disease, body mass index, CRP, SAA, Salb, fibrinogen, apo A-I, and Lp(a) were significantly associated with the risk of all-cause and cardiovascular mortality. During multivariate regression analysis, SAA, fibrinogen, apo A-I, and Lp(a) lost their predictive values, but age and CRP remained powerful independent predictors of both overall death and cardiovascular death.

CONCLUSION

These results suggest that a considerable number of hemodialysis patients exhibit an activated acute phase response, which is closely related to high levels of atherogenic vascular risk factors and cardiovascular death. The mechanisms of activated acute phase reaction in patients on chronic hemodialysis remain to be identified. A successful treatment of the inflammatory condition may improve long-term survival in these patients.

Plasminogen activator inhibitor in plasma: risk factor for recurrent myocardial infarction

Measurements of haemostatic function and metabolic and angiographic indices of risk were included in a prospective cohort study of variables predictive of recurrences within 3 years in 109 unselected men with a first myocardial infarction (MI) before the age of 45. In the course of follow-up, 16 patients had at least one reinfarction (fatal recurrences in 9 and nonfatal in 7) and 1 died suddenly. High plasma concentrations of the fast-acting plasminogen activator inhibitor were independently related to reinfarction along with dyslipoproteinaemia involving VLDL and HDL, poor left ventricular performance, and multiple-vessel coronary artery disease. Besides being independently associated with reinfarction in the present population, high triglyceride levels were possibly connected with a predisposition to thrombosis through a coexisting high level of plasminogen activator inhibitor. The data indicate that reduced fibrinolytic capacity due to increased plasma levels of the plasminogen activator inhibitor predisposes to reinfarction in a complex interplay with atherogenic factors, multiple coronary lesions, and compromised left ventricular function.

Hemostatic factors and the risk of myocardial infarction or sudden death in patients with angina pectoris. European Concerted Action on Thrombosis and Disabilities Angina Pectoris Study Group

BACKGROUND

Increased levels of certain hemostatic factors may play a part in the development of acute coronary syndromes and may be associated with an increased risk of coronary events in patients with angina pectoris.

METHODS

We conducted a prospective multicenter study of 3043 patients with angina pectoris who underwent coronary angiography and were followed for two years. Base-line measurements included the concentrations of selected hemostatic factors indicative of a thrombophilic state or endothelial injury. The results were analyzed in relation to the subsequent incidence of myocardial infarction or sudden coronary death.

RESULTS

After adjustment for the extent of coronary artery disease and other risk factors, an increased incidence of myocardial infarction or sudden death was associated with higher base-line concentrations of fibrinogen (mean +/- SD, 3.28 +/- 0.74 g per liter in patients who subsequently had coronary events, as compared with 3.00 +/- 0.71 g per liter in those who did not; P = 0.01), von Willebrand factor antigen (138 +/- 49 percent vs. 125 +/- 49 percent, P = 0.05), and tissue plasminogen activator (t-PA) antigen (11.9 +/- 4.7 ng per milliliter vs. 10.0 +/- 4.2 ng per milliliter, P = 0.02). The concentration of C-reactive protein was also directly correlated with the incidence of coronary events (P = 0.05), except when we adjusted for the fibrinogen concentration. In patients with high serum cholesterol levels, the risk of coronary events rose with increasing levels of fibrinogen and C-reactive protein, but the risk remained low even given high serum cholesterol levels in the presence of low fibrinogen concentrations.

CONCLUSIONS

In patients with angina pectoris, the levels of fibrinogen, von Willebrand factor antigen, and t-PA antigen are independent predictors of subsequent acute coronary syndromes. In addition, low fibrinogen concentrations characterize patients at low risk for coronary events despite increased serum cholesterol levels. Our data are consistent with a pathogenetic role of impaired fibrinolysis, endothelial-cell injury, and inflammatory activity in the progression of coronary artery disease.

Thrombolysis in Myocardial Infarction (TIMI) Trial--phase I: hemorrhagic manifestations and changes in plasma fibrinogen and the fibrinolytic system in patients treated with recombinant tissue plasminogen activator and streptokinase

Two hundred ninety patients with acute myocardial infarction were treated according to random assignment with an intravenous infusion of either 80 mg of recombinant tissue plasminogen activator (rt-PA) over 3 h or 1.5 million units of streptokinase over 1 h. Patients received an intravenous bolus of heparin (5,000 U [USP]) before pretreatment coronary angiography and a continuous infusion (1,000 U/h) starting 3 h later. The frequency of major and minor hemorrhagic events (33% rt-PA, 31% streptokinase) and associated transfusions (22% rt-PA, 20% streptokinase) were comparable in both groups. More than 70% of bleeding episodes in each group occurred at catheterization or vascular puncture sites. Precipitable fibrinogen levels, measured in plasma samples collected in the presence of a protease inhibitor (aprotinin), declined in rt-PA and streptokinase groups by averages of 26 and 57% at 3 h and by 33 and 58% at 5 h, respectively (rt-PA versus streptokinase, p less than 0.001). At 5 h the plasma plasminogen declined by 57% (rt-PA) and 82% (streptokinase) (p less than 0.001); plasma fibrin(ogen) degradation products were higher in streptokinase-treated patients (244 +/- 12 micrograms/ml, mean +/- SE) than in rt-PA-treated patients (97 +/- 9 micrograms/ml, p less than 0.001). At 27 h, plasma fibrinogen and plasminogen levels were lower and fibrin(ogen) degradation products higher than pretreatment levels in both groups. The frequency of hemorrhagic events was higher in patients with greater changes in plasma factors at 5 h; within treatment groups the levels of fibrin(ogen) degradation products correlated with bleeding complications (p less than 0.005). Thus, in the doses administered, rt-PA induces systemic fibrinogenolysis that is substantially less intense than that induced by streptokinase. The high frequency of bleeding encountered is related to the protocol used, including vigorous anticoagulation, arterial punctures and thrombolytic therapy. These findings emphasize the need for avoidance of invasive procedures and for meticulous care in the selection and management of patients subjected to thrombolytic therapy.

Markers of myocardial damage and inflammation in relation to long-term mortality in unstable coronary artery disease. FRISC Study Group. Fragmin during Instability in Coronary Artery Disease

BACKGROUND

In patients with unstable coronary artery disease, there is a relation between the short-term risk of death and blood levels of troponin T (a marker of myocardial damage) and C-reactive protein and fibrinogen (markers of inflammation). Using information obtained during an extension of the follow-up period in the Fragmin during Instability in Coronary Artery Disease trial, we evaluated the usefulness of troponin T, C-reactive protein, and fibrinogen levels and other indicators of risk as predictors of the long-term risk of death from cardiac causes.

METHODS

Levels of C-reactive protein and fibrinogen at enrollment and the maximal level of troponin T during the first 24 hours after enrollment were analyzed in 917 patients included in a clinical trial of low-molecular-weight heparin in unstable coronary artery disease. The patients were followed for a mean of 37.0 months (range, 1.6 to 50.6).

RESULTS

During follow-up, 1.2 percent of the 173 patients with maximal blood troponin T levels of less than 0.06 microg per liter died of cardiac causes, as compared with 8.7 percent of the 367 patients with levels of 0.06 to 0.59 microg per liter and 15.4 percent of the 377 patients with levels of at least 0.60 microg per liter (P=0.007 and P=0.001, respectively). The rates of death from cardiac causes were 5.7 percent among the 314 patients with blood C-reactive protein levels of less than 2 mg per liter, 7.8 percent among the 294 with levels of 2 to 10 mg per liter, and 16.5 percent among the 309 with levels of more than 10 mg per liter (P=0.29 and P=0.001, respectively). The rates of death from cardiac causes were 5.4 percent among the 314 patients with blood fibrinogen levels of less than 3.4 g per liter, 12.0 percent among the 300 with levels of 3.4 to 3.9 g per liter, and 12.9 percent among the 303 with levels of at least 4.0 g per liter (P=0.004 and P=0.69, respectively). In a multivariate analysis, levels of troponin T and C-reactive protein were independent predictors of the risk of death from cardiac causes.

CONCLUSIONS

In unstable coronary artery disease, elevated levels of troponin T and C-reactive protein are strongly related to the long-term risk of death from cardiac causes. These markers are independent risk factors, and their effects are additive with respect to each other and other clinical indicators of risk.

A definition of advanced types of atherosclerotic lesions and a histological classification of atherosclerosis. A report from the Committee on Vascular Lesions of the Council on Arteriosclerosis, American Heart Association

This report is the continuation of two earlier reports that defined human arterial intima and precursors of advanced atherosclerotic lesions in humans. This report describes the characteristic components and pathogenic mechanisms of the various advanced atherosclerotic lesions. These, with the earlier definitions of precursor lesions, led to the histological classification of human atherosclerotic lesions found in the second part of this report. The Committee on Vascular Lesions also attempted to correlate the appearance of lesions noted in clinical imaging studies with histological lesion types and corresponding clinical syndromes. In the histological classification, lesions are designated by Roman numerals, which indicate the usual sequence of lesion progression. The initial (type 1) lesion contains enough atherogenic lipoprotein to elicit an increase in macrophages and formation of scattered macrophage foam cells. As in subsequent lesion types, the changes are more marked in locations of arteries with adaptive intimal thickening. (Adaptive thickenings, which are present at constant locations in everyone from birth, do not obstruct the lumen and represent adaptations to local mechanical forces). Type II lesions consist primarily of layers of macrophage foam cells and lipid-laden smooth muscle cells and include lesions grossly designated as fatty streaks. Type III is the intermediate stage between type II and type IV (atheroma, a lesion that is potentially symptom-producing). In addition to the lipid-laden cells of type II, type III lesions contain scattered collections of extracellular lipid droplets and particles that disrupt the coherence of some intimal smooth muscle cells. This extracellular lipid is the immediate precursor of the larger, confluent, and more disruptive core of extracellular lipid that characterizes type IV lesions. Beginning around the fourth decade of life, lesions that usually have a lipid core may also contain thick layers of fibrous connective tissue (type V lesion) and/or fissure, hematoma, and thrombus (type VI lesion). Some type V lesions are largely calcified (type Vb), and some consist mainly of fibrous connective tissue and little or no accumulated lipid or calcium (type Vc).

Arterial stiffening and vascular calcifications in end-stage renal disease

BACKGROUND

Epidemiological studies have identified aortic stiffness as an independent predictor of cardiovascular mortality in end-stage renal disease (ESRD) patients. In these patients, aortic pulse wave velocity (PWV) was associated with mediacalcosis, but the influence of arterial calcifications on the viscoelastic properties of large arteries was not well characterized. The purpose of the present study was to analyse the influence of arterial calcifications on arterial stiffness in stable haemodialysed patients.

METHODS

We studied 120 stable ESRD patients on haemodialysis. All patients underwent B-mode ultrasonography of common carotid artery (CCA), aorta, and femoral arteries to determine CCA distensibility, the elastic incremental modulus (Einc), and the presence of vascular calcifications. All patients underwent measurement of aortic PWV and echocardiogram. The presence of calcifications was analysed semiquantitatively as a score (0 to 4) according to the number of arterial sites with calcifications.

RESULTS

Our observations indicate that arterial and aortic stiffness is significantly influenced by the presence and extent of arterial calcifications. The extent of arterial calcifications is in part responsible for increased left ventricular afterload, and is inversely correlated with stroke volume. The influence of calcifications is independent of the role of ageing and blood pressure. Arterial calcifications density increases with age, duration of haemodialysis, the fibrinogen level, and the prescribed dose of calcium-based phosphate binders.

CONCLUSIONS

The results of this study showed that the presence of vascular calcifications in ESRD patients was associated with increased stiffness of large capacity, elastic-type arteries, like the aorta and CCA. The extent of arterial calcifications increased with the use of calcium-based phosphate-binders.

Indices of airway inflammation in induced sputum: reproducibility and validity of cell and fluid-phase measurements

Methods to examine sputum for indices of airway inflammation are evolving. We have examined the repeatability and the validity of an improved method to measure sputum cells and fluid-phase eosinophil cationic protein (ECP), major basic protein (MBP), eosinophil-derived neurotoxin (EDN), albumin, fibrinogen, tryptase, and interleukin-5 (IL-5). Sputum was induced with hypertonic saline twice within 6 d in 10 healthy subjects, 19 stable asthmatics, and 10 smokers with nonobstructive bronchitis. The method included the processing of freshly expectorated sputum separated from saliva, treatment with a fixed proportion of dithiothreitol 0.1% followed by Dulbecco's phosphate-buffered saline, making cytospins, and collecting the supernatant. The reproducibility of measurements, calculated by the intraclass correlation coefficient, was high for all indices measured with the exception of total cell counts and proportion of lymphocytes. Asthmatics, in comparison with healthy subjects and smokers with bronchitis, had a higher proportion of sputum eosinophils (median percent 5.2 versus 0.5 and 0.3), metachromatic cells (0.3 versus 0.07 and 0.08), ECP (1,040 micrograms/L versus 288 and 352), MBP (1,176 micrograms/L versus 304 and 160), and EDN (1,512 micrograms/L versus 448 and 272). Asthmatics differed from healthy subjects, but not from smokers with bronchitis, in the proportion of neutrophils (46.9% versus 24.1%), albumin (704 versus 288 micrograms/mL), and fibrinogen (2,080 versus 440 ng/mL). Smokers with bronchitis showed a trend for a higher neutrophil count and levels of albumin and fibrinogen than healthy subjects. The proportion of sputum eosinophils correlated positively with ECP, MBP, EDN, albumin and fibrinogen levels, and metachromatic cell counts correlated with tryptase. In asthmatics, IL-5 correlated with eosinophil counts. There was a significant negative correlation between sputum indices and expiratory flows and methacholine PC20. Thus, the methods of measuring cell and fluid phase markers in induced sputum used in this study are reproducible and valid. They can therefore be used to reliably measure these indices of airway inflammation.

Lipoprotein-associated phospholipase A2 as an independent predictor of coronary heart disease. West of Scotland Coronary Prevention Study Group

BACKGROUND

Chronic inflammation is believed to increase the risk of coronary events by making atherosclerotic plaques in coronary vessels prone to rupture. We examined blood constituents potentially affected by inflammation as predictors of risk in men with hypercholesterolemia who were enrolled in the West of Scotland Coronary Prevention Study, a trial that evaluated the value of pravastatin in the prevention of coronary events.

METHODS

A total of 580 men who had had a coronary event (nonfatal myocardial infarction, death from coronary heart disease, or a revascularization procedure) were each matched for age and smoking status with 2 control subjects (total, 1160) from the same cohort who had not had a coronary event. Lipoprotein-associated phospholipase A2, C-reactive protein, and fibrinogen levels, and the white-cell count were measured at base line, along with other traditional risk factors. The association of these variables with the risk of coronary events was tested in regression models and by dividing the range of values according to quintiles.

RESULTS

Levels of C-reactive protein, the white-cell count, and fibrinogen levels were strong predictors of the risk of coronary events; the risk in the highest quintile of the study cohort for each variable was approximately twice that in the lowest quintile. However, the association of these variables with risk was markedly attenuated when age, systolic blood pressure, and lipoprotein levels were included in multivariate models. Levels of lipoprotein-associated phospholipase A2 (platelet-activating factor acetylhydrolase), the expression of which is regulated by mediators of inflammation, had a strong, positive association with risk that was not confounded by other factors. It was associated with almost a doubling of the risk in the highest quintile as compared with the lowest quintile.

CONCLUSIONS

Inflammatory markers are predictors of the risk of coronary events, but their predictive ability is attenuated by associations with other coronary risk factors. Elevated levels of lipoprotein-associated phospholipase A2 appear to be a strong risk factor for coronary heart disease, a finding that has implications for atherogenesis and the assessment of risk.

Randomised trial of intravenous recombinant tissue-type plasminogen activator versus intravenous streptokinase in acute myocardial infarction. Report from the European Cooperative Study Group for Recombinant Tissue-type Plasminogen Activator

In a single-blind randomised trial in patients with acute myocardial infarction of less than 6 h duration, the frequency of coronary patency was found to be higher after intravenous administration of recombinant human tissue-type plasminogen activator (rt-PA) than after intravenous streptokinase. 64 patients were allocated to 0.75 mg rt-PA/kg over 90 min, and the infarct-related coronary artery was patent in 70% of 61 assessable coronary angiograms taken 75-90 min after the start of infusion; 65 patients were allocated to 1 500 000 IU streptokinase over 60 min, and the infarct-related vessel was patent in 55% of 62 assessable angiograms. The 95% confidence interval of the differences ranges from +/- 30 to -2% (p = 0.054). Bleeding episodes and other complications were less common in the rt-PA patients than in the streptokinase group. Hospital mortality was identical in the 2 treatment groups. At the end of the rt-PA infusion the circulating fibrinogen level was 61 +/- 35% of the starting value, as measured by a coagulation-rate assay, and 69 +/- 25% as measured by sodium sulphite precipitation. After streptokinase infusion, corresponding fibrinogen levels were 12 +/- 18% and 20 +/- 11%. In the rt-PA group only 4.5% of the fibrinogen was measured as incoagulable fibrinogen degradation products, compared with 30% in the streptokinase group. Activation of the systemic fibrinolytic system was far less pronounced with rt-PA than with streptokinase.

Elevations of inflammatory and procoagulant biomarkers in elderly persons with renal insufficiency

BACKGROUND

Renal insufficiency has been associated with cardiovascular disease events and mortality in several prospective studies, but the mechanisms for the elevated risk are not clear. Little is known about the association of renal insufficiency with inflammatory and procoagulant markers, which are potential mediators for the cardiovascular risk of kidney disease.

METHODS AND RESULTS

The cross-sectional association of renal insufficiency with 8 inflammatory and procoagulant factors was evaluated using baseline data from the Cardiovascular Health Study, a population-based cohort study of 5888 subjects aged > or =65 years. C-reactive protein, fibrinogen, factor VIIc, and factor VIIIc levels were measured in nearly all participants; interleukin-6, intercellular adhesion molecule-1, plasmin-antiplasmin complex, and D-dimer levels were measured in nearly half of participants. Renal insufficiency was defined as a serum creatinine level > or =1.3 mg/dL in women and > or =1.5 mg/dL in men. Multivariate linear regression was used to compare adjusted mean levels of each biomarker in persons with and without renal insufficiency after adjustment for other baseline characteristics. Renal insufficiency was present in 647 (11%) of Cardiovascular Health Study participants. After adjustment for baseline differences, levels of C-reactive protein, fibrinogen, interleukin-6, factor VIIc, factor VIIIc, plasmin-antiplasmin complex, and D-dimer were significantly greater among persons with renal insufficiency (P<0.001). In participants with clinical, subclinical, and no cardiovascular disease at baseline, the positive associations of renal insufficiency with these inflammatory and procoagulant markers were similar.

CONCLUSION

Renal insufficiency was independently associated with elevations in inflammatory and procoagulant biomarkers. These pathways may be important mediators leading to the increased cardiovascular risk of persons with kidney disease.

Outcome results of the Fosinopril Versus Amlodipine Cardiovascular Events Randomized Trial (FACET) in patients with hypertension and NIDDM

OBJECTIVE

ACE inhibitors and calcium antagonists may favorably affect serum lipids and glucose metabolism. The primary aim of the Fosinopril Versus Amlodipine Cardiovascular Events Randomized Trial (FACET) was to compare the effects of fosinopril and amlodipine on serum lipids and diabetes control in NIDDM patients with hypertension. Prospectively defined cardiovascular events were assessed as secondary outcomes.

RESEARCH DESIGN AND METHODS

Inclusion criteria included a diagnosis of NIDDM and hypertension (systolic blood pressure of > 140 mmHg or diastolic blood pressure of > 90 mmHg). Exclusion criteria included a history of coronary heart disease or stroke, serum creatinine > 1.5 mg/dl, albuminuria > 40 micrograms/min, and use of lipid-lowering drugs, aspirin, or antihypertensive agents other than beta-blockers or diuretics. A total of 380 hypertensive diabetics were randomly assigned to open-label fosinopril (20 mg/day) or amlodipine (10 mg/day) and followed for up to 3.5 years. If blood pressure was not controlled, the other study drug was added.

RESULTS

Both treatments were effective in lowering blood pressure. At the end of follow-up, between the two groups there was no significant difference in total serum cholesterol, HDL cholesterol, HbA1c, fasting serum glucose, or plasma insulin. The patients receiving fosinopril had a significantly lower risk of the combined outcome of acute myocardial infarction, stroke, or hospitalized angina than those receiving amlodipine (14/189 vs. 27/191; hazards ratio = 0.49, 95% CI = 0.26-0.95).

CONCLUSIONS

Fosinopril and amlodipine had similar effects on biochemical measures, but the patients randomized to fosinopril had a significantly lower risk of major vascular events, compared with the patients randomized to amlodipine.

The relation of body fat mass and distribution to markers of chronic inflammation

OBJECTIVE

To study the relation of fibrinogen and C-reactive protein (CRP) to various measures of body fat and body fat distribution and to investigate whether these relations were explained by differences in insulin sensitivity.

DESIGN AND SUBJECTS

Cross-sectional analysis of the IRAS (Insulin Resistance Atherosclerosis Study), a large (n=1559) tri-ethnic population (non-Hispanic whites, African-Americans and Mexican-Americans) across different states of glucose tolerance.

MEASUREMENTS

Glucose tolerance (oral glucose tolerance test), insulin sensitivity (frequently sampled intravenous glucose tolerance test and minimal model analysis), assessment of body fat mass and distribution (weight, girths, bioelectrical impedance), subclinical atherosclerosis (B-mode ultrasonography of carotid artery intima-media thickness, IMT), CRP (highly sensitive immunoassay), fibrinogen (standard assay).

RESULTS

Both CRP and fibrinogen were related to all measures of body fat. Strong correlations (correlation coefficient r > or = 0.35) were found between CRP and body mass index (BMI), waist circumference and adipose body mass, respectively. The associations were consistent in non-diabetic and type-2 diabetic subjects, were generally stronger in women, and were only moderately attenuated by the prevailing insulin sensitivity (S(I)). In a multivariate linear regression model waist circumference explained 14.5% of the variability of circulating CRP levels (P=0.0001), BMI 0.4% (P=0.0067), and S(I) 1.7% (P=0.0001). Common carotid artery IMT was related to CRP and fibrinogen in men, but not in women, and was attenuated after adjusting for BMI or waist.

CONCLUSION

Our findings show that measures of body fat are strongly associated with circulating levels of CRP and fibrinogen. These associations were not explained by lower S(I) in obese subjects. Chronic, subclinical inflammation may be one pathophysiological mechanism explaining the increased risk of atherosclerotic disease associated with adiposity.

Tumor necrosis factor and interleukin-1 in the serum of children with severe infectious purpura

Because of the possible involvement of cytokines in gram-negative septicemia, we investigated serum levels of tumor necrosis factor alpha, interleukin-1 beta, alpha interferon, and gamma interferon in children with gram-negative sepsis and purpura fulminans. We studied 55 patients (ages, 1 month to 19 years) with a clinical diagnosis of sepsis and purpuric lesions who were in shock or had three or more other biologic risk factors. The mortality rate was correlated with the number of risk factors present on admission to the hospital (P = 0.03). Tumor necrosis factor alpha was elevated in 91 percent of the 35 patients tested, interleukin-1 in 21 percent of the 33 patients tested, and gamma interferon in 19 percent of the 32 tested. Alpha interferon levels were within normal limits in the 32 patients tested. Serum levels of tumor necrosis factor alpha were positively correlated with the number of risk factors (P less than 0.05) and negatively correlated with blood fibrinogen levels (P = 0.01). Tumor necrosis factor alpha, interleukin-1, and gamma interferon were significantly higher in patients who died than in the survivors. Alpha interferon levels were similar in the two groups. Serum concentrations of both interleukin-1 and gamma interferon were correlated with concentrations of tumor necrosis factor alpha. These data provide evidence that serum levels of tumor necrosis factor alpha, interleukin-1, and gamma interferon correlate with the severity of meningococcemia in children. The findings may have implications for new therapeutic approaches.

The effect of urban air pollution on inflammation, oxidative stress, coagulation, and autonomic dysfunction in young adults

RATIONALE

The biological mechanisms linking air pollution to cardiovascular events still remain largely unclear.

OBJECTIVES

To investigate whether biological mechanisms linking air pollution to cardiovascular events occurred concurrently in human subjects exposed to urban air pollutants.

METHODS

We recruited a panel of 76 young, healthy students from a university in Taipei. Between April and June of 2004 or 2005, three measurements were made in each participant of high-sensitivity C-reactive protein (hs-CRP), 8-hydroxy-2'-deoxyguanosine (8-OHdG), plasminogen activator fibrinogen inhibitor-1 (PAI-1), tissue-type plasminogen activator (tPA) in plasma, and heart rate variability (HRV). Gaseous air pollutants were measured at one air-monitoring station inside their campus, and particulate air pollutants were measured at one particulate matter supersite monitoring station 1 km from their campus. We used linear mixed-effects models to associate biological endpoints with individual air pollutants averaged over 1- to 3-day periods before measurements were performed.

MEASUREMENTS AND MAIN RESULTS

We found that increases in hs-CRP, 8-OHdG, fibrinogen, and PAI-1, and decreases in HRV indices were associated with increases in levels of particles with aerodynamic diameters less than 10 microm and 2.5 microm, sulfate, nitrate, and ozone (O(3)) in single-pollutant models. The increase in 8-OHdG, fibrinogen, and PAI-1, and the reduction in HRV remained significantly associated with 3-day averaged sulfate and O(3) levels in two-pollutant models. There were moderate correlations (r = -0.3) between blood markers of hs-CRP, fibrinogen, PAI-1, and HRV indices.

CONCLUSIONS

Urban air pollution is associated with inflammation, oxidative stress, blood coagulation and autonomic dysfunction simultaneously in healthy young humans, with sulfate and O(3) as two major traffic-related pollutants contributing to such effects.

Extending DerSimonian and Laird's methodology to perform multivariate random effects meta-analyses

Multivariate meta-analysis is increasingly used in medical statistics. In the univariate setting, the non-iterative method proposed by DerSimonian and Laird is a simple and now standard way of performing random effects meta-analyses. We propose a natural and easily implemented multivariate extension of this procedure which is accessible to applied researchers and provides a much less computationally intensive alternative to existing methods. In a simulation study, the proposed procedure performs similarly in almost all ways to the more established iterative restricted maximum likelihood approach. The method is applied to some real data sets and an extension to multivariate meta-regression is described.