High blood hemoglobin concentration as risk factor of major atherosclerotic cardiovascular events in 114,159 healthy men and women in the apolipoprotein mortality risk study (AMORIS)

Association between hemoglobin concentration and hypertension risk in native Tibetans at high altitude

Previous studies examining the association between hemoglobin concentration and hypertension have yielded inconsistent results. There is still a lack of evidence regarding the association between hemoglobin concentration and hypertension risk in native Tibetans at high altitude. We performed this cross-sectional study in Luhuo County of Ganzi Tibetan Autonomous Prefecture (average altitude of 3500 m). In this study, we enrolled 1547 native Tibetans. The association between hemoglobin concentration and hypertension risk was examined by multivariate binary logistic regression and smooth curve fitting. Native Tibetans with hypertension had significantly higher hemoglobin concentrations than those without hypertension (165.9 ± 21.5 g/L vs. 157.7 ± 19.2 g/L, P < 0.001). An increase in hemoglobin concentration of 1 g/L was associated with hypertension (odds ratio [OR] 1.02, 95% confidence interval [CI] 1.01-1.02) after confounder adjustment. The highest hemoglobin concentration group (exceeding 173 g/L) was associated with an increased hypertension risk compared with the bottom quartile of hemoglobin concentration (OR 2.39, 95% CI 1.48-3.85). Hemoglobin concentration (per 1 g/L change) exceeding 176 g/L was significantly associated with an increased hypertension risk (OR 1.04, 95% CI 1.03-1.06). Additionally, high-altitude polycythemia significantly increased the hypertension risk compared with a normal hemoglobin concentration (OR 2.92, 95% CI 1.25-6.86). A similar result was observed for mild polycythemia (OR 1.74, 95% CI 1.29-2.34). In conclusion, hemoglobin concentration was associated with hypertension risk in native Tibetans. When the hemoglobin concentration exceeded a certain value (approximately 176 g/L), the risk of hypertension was significantly increased.

Trends in haemoglobin levels from 1968 to 2017 and association with hormonal contraceptives: observations from the population study of women in Gothenburg, Sweden

AIM

To investigate trends in the haemoglobin (Hb) level in middle-aged Swedish women from 1968 to 2017 and to examine the potential association between Hb and the use of hormonal contraceptives (HCs).

DESIGN

A prospective observational population study of representative 38- and 50-year-old women of Gothenburg, Sweden.

SETTING

The population study of women in Gothenburg started in 1968-1969 and has continued since then with new examinations every 12 years, including both follow-ups and new recruited cohorts. The study consists of both physical examinations and questionnaires.

SUBJECTS

Two thousand four hundred eighty-eight women aged 38 and 50 participated in the study from 1968 to 2017.

STATISTICAL METHODS

Linear regression model analyses were used to analyse linear and non-linear trends in the level of Hb. Linear and logistic regression models were used to analyse possible associations between HC and Hb and possible associations between the use of HC and anaemia, respectively.

MAIN OUTCOME MEASURES AND COVARIATES

Hb was measured in g/L. HC included any ongoing use of HC therapy. Covariates were smoking, body mass index (BMI), alcohol consumption and education.

RESULTS

A non-linear U-shaped trend in mean Hb was seen in the two age groups, 38- and 50-years old. After adjusting for covariates, a significantly higher mean Hb was seen in the 2016-2017 examination compared to 1980-1981, 1992-1993 and 2004-2005. In 38-year-olds, using HC was associated with a reduced risk of anaemia (OR 0.35, 95% CI 0.13-0.75). In both age groups, the use of HC was significantly associated with having a higher Hb.

CONCLUSIONS

Mean levels of Hb in middle-aged women of the general population seem to be increasing again after lower levels in the 1980s and 1990s. The use of HC was associated with having a higher Hb and a lower risk of anaemia in 38-year-old women.

Predictive value of hemoglobin level on early neurological outcomes in acute ischemic stroke

BACKGROUND

Few studies have examined the association between hemoglobin (Hb) levels and early neurological changes following acute ischemic stroke (AIS). The present research investigated whether higher or lower Hb level on admission was associated with early neurological deterioration (END) in AIS patients. Furthermore, we evaluated the predictive effect of Hb concentration on stable or improving outcome.

METHODS

In this prospective cohort study, a total of 1330 patients admitted within 24 hours after AIS onset were finally involved in the analysis. We classified participants into four groups according to baseline Hb levels: ≤120, 121-140, 141-160, and >160 g/L. The risk of END was accessed by means of logistic regression analysis, and tendency of improvement and stability by multinomial logit analysis. We further evaluated the pattern and magnitude of association of Hb as a continuous variable and END by multivariate logistic regression analysis of restricted cubic spline.

RESULTS

Compared with the reference group, hemoglobin >160 g/L was associated with END (OR, 95%CI; 2.149, 1.314-3.512) and severe END (OR, 95% CI as 2.317, 1.351-3.976 and 2.810,1.589-4.968, respectively). Comparatively, higher Hb level also independently predicted improving (OR, 95% CI; 0.322, 0.170-0.609) and stable (OR, 95% CI; 0.371, 0.205-0.673) outcome. Similar results were found when restricted to anterior circulation ischemic stroke after adjustment of variables including large vessel disease.

CONCLUSIONS

We concluded that patients with higher baseline Hb level are at significantly higher risk for END, and less likely to reach stable or improving status at the early stage of stroke.

High haemoglobin levels and mortality in males with intracerebral haemorrhage: a retrospective cohort study

OBJECTIVES

To examine the association between high haemoglobin levels and outcomes in intracerebral haemorrhage (ICH) in a multicentre cohort study.

DESIGN

Prospective multicentre cohort study.

SETTINGS

21 tertiary hospitals across mainland China.

PARTICIPANTS

A total of 5318 consecutive in-hospital spontaneous ICH patients were recruited between January 2012 and June 2016.

PRIMARY AND SECONDARY OUTCOME MEASURES

Haemoglobin levels were measured on admission. Binary or ordinary logistic regression was used to evaluate the independent relationship of haemoglobin level with clinical outcomes at 3 months, measured as death or disability. Restricted cubic spline regression was fitted to examine the potential non-linear shape of the dose-response curve between the whole haemoglobin levels and 3-month poor outcomes.

RESULTS

A total of 5031 patients with ICH were analysed (64.3% male; mean age (SD), 57.8 (15.2) years). We found that the highest haemoglobin quintile was associated with poor outcomes 3 months in males (adjusted OR (aOR) 1.65, 95% CI 1.21 to 2.25) but not in females, which was also observed in the pooled analysis of three subcohorts in male patients (average aOR 1.70, 95% CI 1.23 to 2.33). The spline regression suggested a non-linear association between haemoglobin levels and outcomes and a linear relationship was observed between an elevated haemoglobin level and 3-month disability/death in males (haemoglobin level per 10 g/L: aOR 1.24, 95% CI 1.10 to 1.40, p<0.001), which was mediated by larger haematoma volume (effect size: 0.115, 95% CI 0.012 to 0.231).

CONCLUSIONS

This study found a sex-specific association between an elevated haemoglobin level and poor 3-month outcomes, which might be mediated by larger haematoma volume.

The levels of hemoglobin are positively associated with arterial stiffness in community-dwelling Chinese adults

BACKGROUND AND AIMS

Hemoglobin (Hb) concentrations are known to be related to cardiovascular diseases. This study investigated the association between Hb levels and arterial stiffness, as assessed by measurement of the brachial-ankle pulse wave velocity (baPWV).

METHODS AND RESULTS

3576 adults (2139 males and 1437 females) from the general Chinese population who had their physical check-ups in the health examination centers of Jiangmen Central Hospital were enrolled into the study. The anthropometrics and laboratory data as well as the baPWV and Hb levels were subsequently obtained. Age-adjusted partial correlation and multivariable stepwise linear regression analyses were used to evaluate the relationships between Hb and baPWV for men and women separately. In both sexes, Hb levels were positively associated with body mass index, total cholesterol, low-density lipoprotein cholesterol, triglycerides, glutamic-pyruvic transaminase, γ-glutamyltranspeptidase, uric acid and baPWV, but negatively correlated with the estimated glomerular filtration rate. Multivariable linear regression analysis showed that Hb was significantly and independently associated with arterial stiffness in men (β = 0.043, 95% CI 0.010-0.077, p < 0.05) and women (β = 0.035, 95% CI 0.001-0.069, P < 0.05), after adjustment for confounding factors.

CONCLUSION

The data indicate that high Hb concentration significantly correlate with increased baPWV in general Chinese population.

Association of serum hemoglobin level with the risk of carotid plaque beyond metabolic abnormalities among asymptomatic adults without major adverse clinical events: a cross-sectional cohort study

BACKGROUND

The serum hemoglobin (Hb) level is closely related to adverse clinical outcomes. However, data on the association of Hb levels with subclinical atherosclerosis beyond metabolic abnormalities are limited.

METHODS

This study evaluated the association among serum Hb level, metabolic syndrome (MetS), and the risk of carotid plaque formation in asymptomatic adults without a history of major adverse clinical events.

RESULTS

A total of 2560 participants (mean age: 60 ± 8 years, 32.9% men) were stratified into four groups based on Hb quartiles, as follows: ≤ 12.8 g/dL (group I), 12.9-13.6 g/dL (group II), 13.7-14.5 g/dL (group III), and ≥ 14.6 g/dL (group IV). The overall prevalence of MetS and carotid plaque was 37.2% and 33.4%, respectively. The prevalence of MetS increased with increasing Hb level (group I: 27.4% vs. group II: 35.9% vs. group III: 42.6% vs. group IV: 44.1%, p < 0.001). The prevalence of carotid plaque was 34.3%, 28.1%, 32.8%, and 39.5% in groups I, II, III, and IV, respectively. Univariate logistic regression analysis showed that MetS was associated with an increased risk of carotid plaque (odds ratio [OR] 1.568, 95% confidence interval [CI] 1.326-1.856, p < 0.001). Only group II showed a lower risk of carotid plaque than group I (OR 0.750, 95% CI 0.596-0.943, p = 0.014). Multiple logistic regression models showed consistent results after adjusting for clinical factors, including MetS and its individual components.

CONCLUSION

Serum Hb level is associated with the risk of carotid plaque beyond MetS and its components in a relatively healthy adult population.

Association of Alk1 and Endoglin Polymorphisms with Cardiovascular Damage

Cardiovascular diseases are associated to risk factors as obesity, hypertension and diabetes. The transforming growth factor-β1 receptors ALK1 and endoglin regulate blood pressure and vascular homeostasis. However, no studies relate the association of ALK1 and endoglin polymorphisms with cardiovascular risk factors. We analysed the predictive value of the ALK1 and endoglin polymorphisms on cardiovascular target organ damage in hypertensive and diabetic patients in 379 subjects with or without hypertension and diabetes in a Primary Care setting. The ALK1 rs2071219 polymorphism (AA genotype) is associated with a lower presence of diabetic retinopathy and with the absence of altered basal glycaemia. Being carrier of the ALK1 rs3847859 polymorphism (G allele) is associated with lower basal heart rate and with higher LDL-cholesterol levels. The endoglin rs3739817 polymorphism (AA genotype) is associated with higher levels of LDL-cholesterol, and being carrier of the endoglin rs10987759 polymorphism (C allele) is associated with higher haemoglobin levels and with an increased heart rate. Summarizing, several ALK1 and endoglin gene polymorphisms increase the risk of cardiovascular events. The analysis of these polymorphisms in populations at risk, in combination with the determination of other parameters and biomarkers, could implement the diagnosis and prognosis of susceptibility to cardiovascular damage.

Hemoglobin level and three-month clinical outcomes among ischemic stroke patients with elevated systolic blood pressure

BACKGROUND

Previous studies have reported that extreme low and high hemoglobin levels are positively associated with the risk of ischemic stroke. However, there are few reports on the relationship between hemoglobin at acute phase and clinical outcomes after ischemic stroke and the results of their association to date are inconsistent. We aimed to investigate the association between them in a large prospective cohort of ischemic stroke patients.

METHODS

Baseline hemoglobin levels were measured in 3881 patients with acute ischemic stroke. The primary outcome was defined as composite outcome of major disability and death (modified Rankin Scale score ≥ 3) at 3 months after stroke onset. Secondary outcomes were separately those of major disability and death.

RESULTS

Compared with the lowest quartile of hemoglobin, the multivariate adjusted odds ratios (95% confidence intervals) associated with the highest quartile were 1.38 (1.03-1.86), 1.49 (1.11-1.99), 0.79 (0.41-1.52) for primary outcome, major disability and death, respectively. Multiple-adjusted spline regression model showed linear associations of hemoglobin levels with primary outcome (P for linearity =0.037) and major disability (P for linearity =0.004). Subgroup analyses further confirmed the positive association between high hemoglobin and poor prognosis of ischemic stroke.

CONCLUSIONS

Elevated hemoglobin levels in the acute phase were associated with poor prognosis at 3 months after ischemic stroke. Further prospective studies from other samples of ischemic stroke patients are needed to validate our findings.

Association Between Changes in Hemoglobin Concentration and Cardiovascular Risks and All-Cause Mortality Among Young Women

Background Anemia is considered to increase the risk of mortality in high-risk populations, but its effect has not been examined among young populations. This study aimed to determine the effect of hemoglobin (Hb) concentration and its changes on the risk of acute myocardial infarction ( AMI ), stroke, cerebrovascular disease and all-cause mortality among young women. Methods and Results We analyzed data from the Korean National Health Information Database on 808 143 women aged 20 to 39 years without any cardiocerebrovascular disease. A 1-time Hb concentration and changes in Hb over a 2-year period were calculated as exposures. Participants were followed for a median of 10 years to determine the risk of AMI , stroke, cerebrovascular disease, and all-cause mortality. There were U- or J-shaped associations between Hb concentration or change in Hb and AMI , stroke, cerebrovascular disease, and all-cause mortality. Increasing the Hb concentration from normal to high increased the risk for AMI (hazard ratio [95% confidence interval]: 1.49 [1.08-2.04]). With regard to the risk for stroke, increasing the Hb concentration from a normal to a high range increased the risk (hazard ratio [95% confidence interval]: 1.10 [1.02-1.35]), and decreasing the Hb concentration from a high to a normal range decreased this risk (hazard ratio [95% confidence interval]: 0.80 [0.60-0.97]). Improving anemia to the normal Hb range decreased all-cause mortality (hazard ratio [95% confidence interval]: 0.81 [0.69-0.94]); however, overcorrection of Hb concentration (Hb≥14.0 g/dL) was not significant. Conclusions These findings suggest that regular Hb analysis may assist in identifying young women who are at risk of AMI , stroke, cerebrovascular disease, and all-cause mortality.

The Methylenetetrahydrofolate Reductase C677T (rs1801133) and Apolipoprotein A5-1131T>C (rs662799) Polymorphisms, and Anemia Are Independent Risk Factors for Ischemic Stroke

BACKGROUND

Although there is adequate knowledge as to the role of traditional cardiovascular risk factors on stroke incidence, knowledge of other risk factors, particularly genetic ones, is still incomplete.

METHODS

To assess the participation of some polymorphisms, along with other modifiable risk factors, a case-control study was conducted. A total of 253 cases were identified in the emergency room of a general regional hospital, with a clinical trait of stroke confirmed by a skull computerized axial tomography scan. In the surgery ward, 253 controls were identified, gender and age (±5 years) matched. Biochemical parameters were measured, and 4 polymorphisms were genotyped by polymerase chain reaction, rs1801133 (methylenetetrahydrofolate reductase [MTHFR]), rs1498373 (dimethylarginine dimethylaminohydrolase type 1 [DDAH1]), rs662799 (apolipoprotein A5 [APOA5]), and rs1799983 (endothelial nitric oxide). Odds ratios were estimated to assess the strength of association, with 95% confidence intervals, both in a matched case-control analysis and in a conditional regression analysis.

RESULTS

Cases had higher mean blood pressure and triglycerides and lower hemoglobin levels. Heterozygous and homozygous subjects to the rs1801133 variant of the MTHFR gene had a 3-fold higher risk of stroke. In the dominant model, those with the polymorphism rs662799 of the promoter region for APOA5 had twice the risk of stroke. Anemia increased the risk of stroke 4-fold.

CONCLUSIONS

Polymorphisms of the genes MTHFR (rs1801133) and APOA5 (rs662799), as well as anemia, are independent risk factors for stroke in Mexicans, together with traditional cardiovascular risk factors such as high triglycerides and high blood pressure.

Carotid Atheroma From Men Has Significantly Higher Levels of Inflammation and Iron Metabolism Enabled by Macrophages

BACKGROUND AND PURPOSE

Men differ from women in the manifestation of atherosclerosis and iron metabolism. Intraplaque hemorrhage and hemoglobin (Hb) catabolism by macrophages are associated with atherosclerotic lesion instability. The study aims were to investigate sex differences in (1) lesion severity in relation to blood Hb, (2) iron homeostasis in human carotid plaques, and (3) macrophage polarization within atheroma.

METHODS

The carotid artery samples from 39 men and 23 women were immunostained with cell markers for macrophages, smooth muscle cells, ferritin, and TfR1 (transferrin receptor 1), which were further analyzed according to sex in relation to iron, Hb, and lipids in circulation. Additionally, samples of predefined regions from human carotid atherosclerotic lesions, including internal controls, were used for proteomic analysis by mass spectrometry.

RESULTS

Male patients, compared with women, had larger necrotic cores and more plaque rupture, which were associated with higher levels of Hb. Atheroma of male patients had significantly higher levels of Hb in circulation and CD68 macrophages, ferritin, and TfR1 in lesions. CD68 macrophages were significantly correlated with ferritin and TfR1. Plaques from male patients comparatively possessed higher levels of inflammatory macrophage subsets, CD86 (M1) and CD163 (M2), but lower levels of STF (serotransferrin) and HPX (hemopexin).

CONCLUSIONS

Male patients with carotid atheroma had more advanced and ruptured lesions associated with significantly higher levels of inflammatory macrophage infiltration and high iron stores in the blood and in their plaques. These findings help to understand sex differences and iron metabolism in atherosclerosis and factors related to atheroma progression.

Acute ischemic stroke and abnormal blood hemoglobin concentration

OBJECTIVES

This study examines whether low or high blood hemoglobin concentration (HGB) is associated with stroke severity, worse clinical outcomes, and poorer prognosis after acute ischemic stroke (AIS).

METHODS

This retrospective cohort study included data from the Ontario Stroke Registry on consecutive patients with AIS who were admitted between July 2003 and March 2008. We excluded patients taking anticonvulsants or iron supplement; patients with cancer, renal failure, history of gastro-intestinal or genitourinary bleeding, and pregnancy. Patients were divided into groups as follows: low HGB, normal HGB, and high HGB. Outcome measures included the frequency of greater degree of disability at discharge (modified Rankin score: 3-6), 7-day, 30-day and 90-day mortality, and length of stay in the acute stroke care hospital.

RESULTS

Hemoglobin levels higher than the upper limit of normal are associated with a greater disability at discharge (OR = 1.49, 95% CI: 1.03-2.15, P = 0.0331), and higher 30-day mortality (HR = 1.98, 95% CI: 1.44-2.74, P < 0.0001) after adjustment for major potential confounders. The Kaplan-Meier curves indicate that abnormal HGB levels are associated with higher mortality after AIS (P < 0.0001). HGB levels below the lower limit of normal are associated with longer lengths of stay in the acute care hospital (OR = 1.11, 95% CI: 1.02-1.22, P = 0.017). Elevated HGB was associated with greater neurological deficit on admission (OR = 1.45, 95% CI: 1.06-1.95, P = 0.0195).

CONCLUSIONS

Our results suggest that an elevated HGB on the initial admission is associated with more severe strokes, greater disability at discharge, and higher 30-day mortality after AIS. A low HGB on admission is associated with longer stay in the acute care hospital.

Oxidative stress, HDL functionality and effects of intravenous iron administration in women with iron deficiency anemia

BACKGROUND AND AIMS

Iron deficiency anemia (IDA) affects around 20-30% of adults worldwide. An association between IDA and cardiovascular disease (CVD) has been reported. Oxidative stress, inflammation and low concentration of high-density lipoproteins (HDL) were implicated on endothelial dysfunction and CVD in IDA. We studied the effects of iron deficiency and of an intravenous iron administration on oxidative stress and HDL characteristics in IDA women.

METHODS

Two studies in IDA women are presented: a case-control study, including 18 patients and 18 age-matched healthy women, and a follow-up study 72hr after the administration of intravenous iron (n = 16). Lipids, malondialdehyde, cholesteryl ester transfer protein (CETP), paraoxonase-1 (PON-1) and HDL chemical composition and functionality (cholesterol efflux and antioxidative activity) were measured. Cell cholesterol efflux from iron-deficient macrophages to a reference HDL was also evaluated.

RESULTS

IDA patients showed higher triglycerides and CETP activity and lower HDL-C than controls (all p < 0.001). HDL particles from IDA patients showed higher triglyceride content (+30%,p < 0.05) and lower antioxidative capacity (-23%,p < 0.05). Although HDL-mediated cholesterol efflux was similar between the patients and controls, iron deficiency provoked a significant reduction in macrophage cholesterol efflux (-25%,p < 0.05). Arylesterase activity of PON-1 was significantly lower in IDA patients than controls (-16%,p < 0.05). The intravenous administration of iron was associated with a decrease in malondialdehyde levels and an increase in arylesterase activity of PON-1 (-22% and +18%, respectively, p < 0.05).

CONCLUSION

IDA is associated with oxidative stress and functionally deficient HDL particles. It remains to be determined if such alterations suffice to impair endothelial function in IDA.

Four-year stability of anthropometric and cardio-metabolic parameters in a prospective cohort of older adults

AIM

To examine the medium-term stability of anthropometric and cardio-metabolic parameters in the general population.

MATERIALS & METHODS

Participants were 5160 men and women from the English Longitudinal Study of Ageing (age ≥50 years) assessed in 2004 and 2008. Anthropometric data included height, weight, BMI and waist circumference. Cardio-metabolic parameters included blood pressure, serum lipids (total cholesterol, HDL, LDL, triglycerides), hemoglobin, fasting glucose, fibrinogen and C-reactive protein.

RESULTS

Stability of anthropometric variables was high (all intraclass correlations >0.92), although mean values changed slightly (-0.01 kg weight, +1.33 cm waist). Cardio-metabolic parameters showed more variation: correlations ranged from 0.43 (glucose) to 0.81 (HDL). The majority of participants (71-97%) remained in the same grouping relative to established clinical cut-offs.

CONCLUSION

Over a 4-year period, anthropometric and cardio-metabolic parameters showed good stability. These findings suggest that when no means to obtain more recent data exist, a one-time sample will give a reasonable approximation to average levels over the medium-term, although reliability is reduced.

Hemoglobin concentration and risk of cardiovascular disease in Korean men and women - the Korean heart study

This study investigated the relationship between hemoglobin concentration and the incidence of cardiovascular diseases (CVD). A total of 407,858 subjects (256,851 men, aged 30-94 yr), who underwent physical examination at 17 Korean nationwide health examination centers, was included in this study. Data regarding CVD incidence were obtained from the Korean National Health Insurance database. In Cox proportional hazard models, men with lower or higher hemoglobin level showed higher hazard ratios (HR) with total CVD (HR, 1.14; 95% Confidence interval [CI], 1.08-1.21 for the 1st quintile; HR, 1.14; 95% CI, 1.09-1.21 for the 5th quintile), ischemic heart disease (HR, 1.16; 95% CI, 1.07-1.26 for the 1st quintile; HR, 1.16; 95% CI, 1.07-1.25 for the 5th quintile), and stroke (HR, 1.13; 95% CI, 1.02-1.25 for the 1st quintile; HR, 1.18; 95% CI, 1.07-1.30 for the 5th quintile) compared to those with mid-level of hemoglobin (3rd quintile). Women with higher hemoglobin level showed higher HR with total CVD (HR, 1.15; 95% CI, 1.01-1.31 for pre-menopausal women; HR, 1.08; 95% CI, 1.01-1.16 for post-menopausal women). We found an independent U-shaped association between hemoglobin level and CVD incidence in Korean population.

Usefulness of hemoglobin level to predict long-term mortality in patients with asymptomatic carotid narrowing by ultrasonography

Anemia is associated with the cardiovascular outcome in healthy subjects but its impact on outcome in patients with cardiovascular disease has not yet been fully understood. Therefore, we assessed the long-term influence of hemoglobin on all-cause and cardiovascular mortality in patients with atherosclerotic disease. We prospectively studied 1,065 of 1,286 consecutive patients with asymptomatic carotid narrowing. During a median follow-up of 6.2 years, corresponding to 5,551 overall person-years, 275 patients (25.8%) died. Continuous measures of hemoglobin displayed a significant inverse effect on all-cause mortality and cardiovascular mortality (adjusted hazard ratio [HR] for increase of 1 SD of hemoglobin 0.73, 95% confidence interval [CI] 0.64 to 0.83; p <0.001) and adjusted HR 0.76, 95% CI 0.64 to 0.89; p = 0.001, respectively). The cumulative 6-year survival rate was 61%, 79%, 80%, and 81% in the first, second, third, and fourth quartile of hemoglobin (log-rank p <0.001). Patients within the first quartile (<12.9 g/dl) had a significantly increased risk of all-cause mortality (adjusted HR 1.93, 95% CI 1.46 to 2.54, p <0.001) and cardiovascular mortality (adjusted HR 1.68, 95% CI 1.19 to 2.36, p = 0.003) compared to patients with greater levels. In conclusion, our study has demonstrated a significant association with hemoglobin levels and all-cause and cardiovascular mortality in patients with carotid narrowing. Nevertheless, additional research, in terms of randomized controlled trials, is needed to warrant these findings and to evaluate potential therapeutic interventions.

Model comparisons of competing risk and recurrent events for graft failure in renal transplant recipients

BACKGROUND AND OBJECTIVES

Risk factor analysis of long-term graft survival in kidney transplant recipients is usually based on Cox regression models of time to first occurrence of doubling of serum creatinine or graft loss (DSCGL). However, death is a competing cause of failure, and censoring patients who die could bias estimates. We therefore compared estimates of time to first event versus estimates that included death as a competing risk and recurrent events.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A Cox regression analysis of 1997-2002 data from the Assessment of Lescol in Renal Transplant (ALERT) trial population identified an eight-factor risk model, by analyzing time to first occurrence of DSCGL. The same factors were re-analyzed, allowing for death as competing. The probability of survival free of DSCGL was estimated; and two recurrent models (marginal and conditional) were used for time to events.

RESULTS

Creatinine, systolic BP, and HLA-DR mismatches lost 33%-46% of their strength of association with DSCGL when death was included as a competing risk. Small changes were observed if recurrent events were analyzed in the marginal model.

CONCLUSION

The relationship between serum creatinine and DSCGL was attenuated when death was considered as a competing risk; inclusion of recurrent events had little effect. These findings have important implications for analysis and trial design in populations at high mortality risk.

NFAT regulates the expression of AIF-1 and IRT-1: yin and yang splice variants of neointima formation and atherosclerosis

AIMS

Alternative transcription and splicing of the allograft inflammatory factor-1 (AIF-1) gene results in the expression of two different proteins: AIF-1 and interferon responsive transcript-1 (IRT-1).  Here, we explore the impact of AIF-1 and IRT-1 on vascular smooth muscle cell (VSMC) activation and neointima formation, the mechanisms underlying their alternative splicing, and associations of AIF-1 and IRT-1 mRNA with parameters defining human atherosclerotic plaque phenotype.

METHODS AND RESULTS

Translation of AIF-1 and IRT-1 results in different products with contrasting cellular distribution and functions. Overexpression of AIF-1 stimulates migration and proliferation of human VSMCs, whereas IRT-1 exerts opposite effects. Adenoviral infection of angioplasty-injured rat carotid arteries with AdAIF-1 exacerbates intima hyperplasia, whereas infection with AdIRT-1 reduces neointima. Expression of these variants is modulated by changes in nuclear factor of activated T-cells (NFAT) activity.  Pharmacological inhibition of NFAT or targeting of NFATc3 with small interfering RNA (siRNA) lowers the AIF-1/IRT-1 ratio and favours an anti-proliferative outcome.  NFAT acts as a repressor on the IRT-1 transcriptional start site, which is also sensitive to interferon-γ stimulation. Expression of AIF-1 mRNA in human carotid plaques associates with less extracellular matrix and a more pro-inflammatory plaque and plasma profile, features that may predispose to plaque rupture. In contrast, expression of IRT-1 mRNA associates with a less aggressive phenotype and less VSMCs at the most stenotic region of the plaque.

CONCLUSION

Inhibition of NFAT signalling, by shifting the AIF-1/IRT-1 ratio, may be an attractive target to regulate the VSMC response to injury and manipulate plaque stability in atherosclerosis.