Exploring circulating biomarkers for risk prediction of incident atrial fibrillation – insights from the BiomarCaRE project

Background

Atrial fibrillation (AF) remains a major health issue in Europe and worldwide. Risk prediction is crucial to identify at-risk individuals and prevent subsequent complications of AF such as stroke and heart failure. Biomarker-enriched, personalized risk prediction offers great potential for population-wide prevention beyond traditional cardiovascular risk factors.

Purpose

We aimed to identify robust predictors for incident AF using classical regressions and machine learning (ML) techniques within a broad spectrum of candidate variables.

Methods

Three European community cohorts from the Biomarkers for Cardiovascular Risk Assessment in Europe (BiomarCaRE) consortium were included to explore the predictive utility of 14 biomarkers mirroring distinct pathophysiological pathways of AF including lipids, inflammation (C-reactive protein [CRP]), renal, and myocardium-specific markers (N-terminal pro B-type natriuretic peptide [NT-proBNP], high-sensitivity troponin I [hsTnI]) within a population-based sample of 42,280 individuals free of AF at baseline. Investigated biomarkers were examined in relation to incident AF using Cox regressions adjusted for multiple cardiovascular risk factors, and additionally by C-indices and net reclassification improvement (NRI) when compared to a reference model incorporating clinical variables. Their predictive utility for incident AF was further analyzed using different ML methods, including Least Absolute Shrinkage and Selection Operator (LASSO) and Random Survival Forest (RSF).

Results

Of 42,280 individuals (21,843 women [51.7%]; median [interquartile range, IQR] age, 52.2 [42.6, 62.0] years), 1496 (3.5%) developed AF during a median follow-up time of 5.7 years. In multivariable-adjusted Cox regression analysis, NT-proBNP was the strongest circulating predictor of incident AF (hazard ratio [HR] per standard deviation [SD] 1.93, 95% CI 1.82–2.04; P<0.001). Further, hsTnI (HR per SD 1.18, 95% CI 1.13–1.22; P<0.001), cystatin C (HR per SD 1.16, 95% CI 1.10–1.23; P<0.001) and CRP (HR per SD 1.08, 95% CI 1.02–1.14, P=0.012) correlated positively with new-onset AF. NT-proBNP enhanced model discrimination (ΔC-index 0.037, 95% CI 0.029–0.044) markedly and yielded the best reclassification improvement (NRI 0.237, 95% CI 0.187–0.287) when compared to the clinical model. Neither the addition of hsTnI to NT-proBNP, nor a model comprising all investigated biomarkers further increased discrimination or reclassification substantially. In different ML models, NT-proBNP and age were the strongest predictors of incident AF.

Conclusions

Using a dual approach with both classical regressions and modern ML methods, NT-proBNP consistently remained the strongest blood-based predictor of incident AF with relevant discriminative ability and reclassification yield beyond classical cardiovascular risk factors. The clinical benefit of these findings for AF risk prediction needs to be tested prospectively.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): BiomarCaRE (FP7, HEALTH-F2-2011-278913)European Union's Horizon 2020 research and innovation programme (grant agreement number 847770, AFFECT-EU)

Risk factors and prognosis for heart failure in atrial fibrillation subtypes in women and men

Background

Atrial fibrillation (AF) and heart failure (HF) are common diseases that often co-exist and substantially impact both morbidity, mortality, and quality of life. Although there has been an increasing amount of research on HF in AF patients, there is limited knowledge on the association of AF subtypes (paroxysmal/persistent, permanent) with HF in women and men.

Purpose

To explore the sex-specific association between incident AF subtypes and HF risk factors and mortality in AF participants in a general population.

Methods

A total of 14,798 women and 13,197 men aged 25 years and older were enrolled from 1994 to 2008 and followed up for incident AF and HF through 2016. Cox proportional hazards regression analysis was conducted to provide sex- and AF subtype-specific hazard ratios (HRs) for the risk of HF, risk factors for HF and joint influence on mortality when AF precedes HF. Participants without AF and HF were used as reference. In the analysis of risk factors for HF we included only those who developed AF, and the follow-up period started at the date of first detected AF. Models were adjusted for systolic blood pressure, body mass index (BMI), total cholesterol, current smoking, physical activity, and history of myocardial infarction, angina pectoris, stroke, and diabetes mellitus, as well as age, with age as the time scale in the regression models.

Results

Over a median follow-up of 21.6 years, incident AF occurred in 856 women (471 with paroxysmal/persistent AF and 385 with permanent AF) and 1,036 men (587 with paroxysmal/persistent AF and 449 with permanent AF). Incident HF occurred in 761 women and 930 men. In both sexes, there was an increased risk of HF when AF was present. For permanent AF, women had a significantly higher risk of HF than men (HR 10.50, 95% CI 8.72–12.66 vs. HR 8.11, 95% CI 6.81–9.67). Permanent AF, current smoking, and prevalent myocardial infarction were significant risk factors for HF in AF participants in both sexes, while hypertension was only associated with increased risk of HF in women and BMI and prevalent stroke in men. Higher physical activity level was associated with reduced risk of AF in both sexes. The risk of death increased when HF succeeded AF. For women the risk of mortality was higher for permanent AF (HR 3.83, 95% CI 3.19–4.61 vs. HR 2.98, 95% CI 2.34–3.80), while in men it was highest for paroxysmal/persistent AF (HR 3.67, 95% CI 2.94–4.58 vs. HR 2.91, 95% CI 2.37–3.57), but there was no significant difference between sexes.

Conclusions

All AF subtypes were associated with an increased risk of HF in both sexes. For permanent AF, women had a significantly higher risk than men. Several risk factors for HF in AF participants were similar between sexes. However, hypertension was only a risk factor in women, whereas BMI and prevalent stroke were only risk factors in men. In AF participants, subsequent development of HF was associated with increased mortality in both sexes.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): UiT The Arctic University of Norway

Time trends in cardiovascular risk factors across levels of education in a general population

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Northern Norway Health Authority

Background

Favourable changes over time in population cardiovascular disease (CVD) risk has not benefitted all socioeconomic groups equally. Social inequality in health also exists in high-income countries with an egalitarian welfare system.

Purpose

We aimed to study CVD risk factors across educational groups over time in a Norwegian general population.

Methods

We used multivariable linear regression and generalised estimating equation models with age-adjusted means and proportions to examine CVD risk (smoking, physical activity level, obesity [body mass index ≥30 kg/m2], blood pressure, total- and low-density lipoprotein [LDL] cholesterol, and total risk of CVD [estimated 10-year risk with NORRISK 2]) across four levels of education: Primary/partly secondary up to 10 years of schooling, upper secondary, tertiary <4 years, tertiary ≥4 years in women and men aged 40-79 years attending a population-based study with two consecutive surveys in 2007-2008 (N=11,941) and 2015-2016 (N=20,322).

Results

In women, the difference between the lowest and the highest education level in risk factors in 2007-2008 versus 2015-2016 was for smoking 22.0 vs 19.2 percentage points (pp), obesity 8.7 vs 8.8 pp, sedentary physical activity level 10.5 vs 11.5 pp (p=0.012), systolic blood pressure 5.5 vs 3.4 mmHg (p=0.001), total cholesterol 0.2 mmol/L vs no difference (p<0.001), LDL cholesterol 0.3 vs 0.1 mmol/L (p<0.001), and total CVD risk 0.9 vs 1.8 (p<0.001), respectively. In men, the corresponding numbers were for smoking 20.1 vs 16.8 pp, obesity 9.9 vs 12.9 pp, sedentary physical activity level 10 vs 11.5 pp (p=0.027), systolic blood pressure 1.7 vs 1.7 mmHg, total cholesterol 0.2 mmol/L vs no difference (p<0.001), LDL cholesterol 0.1 mmol/L vs no difference (p<0.001), and total CVD risk 1.2 vs 0.9, respectively. No difference across educational levels and time regarding blood pressure or total- or LDL cholesterol in users of antihypertensives and lipid-lowering drugs was found, except for an educational difference in the first but not the second time period in female antihypertensive users.

Conclusion

We found a clinically relevant educational gap in CVD risk factors, with more favourable levels with higher education. Over time, the educational gap increased in physical activity in both sexes, and in total CVD risk in women. Further, the educational gap declined in blood lipids in both sexes, and in systolic blood pressure in women. While medication use seems to contribute to weaken the educational gradient in blood pressure and lipid levels, a stronger emphasis on lifestyle interventions is needed to reduce the educational inequalities in behavioural CVD risk factors.

Risk factors, subsequent disease onset and prognostic impact of myocardial infarction and atrial fibrillation

Background

Myocardial infarction (MI) is a known risk factor for incident atrial fibrillation (AF), while AF frequently complicates acute MI. Although both diseases share common cardiovascular risk factors, the direction and strength of the association of the risk factors with disease onset, subsequent disease incidence and mortality are not completely understood.

Purpose

Our goal was to define the temporal relationship of MI and AF and the association of cardiovascular risk factors with disease incidence in order to determine whether common clinical risk factors show different associations with incident MI or AF. We further aimed to investigate predictors of subsequent disease onset and the impact of subsequent disease diagnosis on mortality.

Methods

In pooled multivariable Cox regression analyses we examined temporal relations of disease onset and identified predictors of MI, AF and subsequent all-cause mortality in 108,363 individuals (median age 46.0 years, 48.2% men) free of MI and AF at baseline from six European population-based cohorts.

Results

Over a maximum follow-up of 10.0 years 3558 (3.3%) individuals were diagnosed exclusively with MI, 1922 (1.8%) with AF but no MI, and 491 (0.5%) individuals developed both MI and AF. Association of male sex, systolic blood pressure, antihypertensive treatment and diabetes mellitus appeared to be stronger with incident MI than with AF, whereas increasing age and body mass index showed a higher risk for incident AF. Total cholesterol and daily smoking were significantly related to incident MI but not AF. The combined population attributable fraction of the cardiovascular risk factors was over 70% for incident MI, whereas it was only about one quarter for incident AF. Subsequent MI after incident AF (hazard ratio1.68, 95% CI 1.03–2.74) and subsequent AF after MI (hazard ratio 1.75, 95% CI 1.31–2.34) both significantly increased overall mortality risk.

Conclusions

Subsequent diagnosis of MI and AF was associated with a significant increase in mortality, irrespective of the first event. We found different associations of common cardiovascular risk factors with incident MI and AF indicating distinct pathophysiological pathways in disease development.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union's Horizon 2020 research and innovation programme (grant agreement No 847770, AFFECT-EU) European Union's Horizon 2020 research and innovation programme (grant agreement No 648131)

Treatment target achievement after myocardial infarction: cardiovascular risk factors, medication use and lifestyle in Norwegian women and men

Funding Acknowledgements

Type of funding sources: None.

Background

Although the use of guidelines in clinical practice is emphasised, large multi-center studies of patients with cardiovascular disease have shown secondary prevention to be suboptimal, which increase the risk of recurrent events.

Purpose

To examine ESC guideline treatment target achievement after myocardial infarction for cardiovascular risk factors, medication use and a broad range of lifestyle factors in women and men from a Norwegian general population.

Methods

In a population-based study conducted 2015-2016 (65% attendance), 637 participants 40-95 years (23% women, 70% ≥65 years) had validated myocardial infarction. Cross-sectionally, we investigated target achievement for blood pressure (<140/90 mmHg, <130/80 mmHg if diabetes), LDL cholesterol (<1.8 mmol/L), HbA1c (<7.0% if diabetes), weight (body mass index (BMI) <25 kg/m2, waist circumference (women <80 cm, men <94 cm)), smoking (non-smoking), physical activity (self-reported >sedentary, accelerometer-measured moderate-to-vigorous ≥150 min/week), diet (intake of fruits ≥200 g/day, vegetables ≥200 g/day, fish ≥200 g/week, saturated fat <10E%, fiber ≥30g/day,  and alcohol (women ≤10 g/day, men ≤20 g/day)), and medication use (antihypertensives, lipid-lowering drugs, antithrombotics, antidiabetics) using regression models.

Results

Proportion of target achievement was for blood pressure 55.8%, LDL cholesterol 9.3%, HbA1c 42.7%, BMI 19.5%, waist circumference 15.6%, non-smoking 86.2%, self-reported physical activity 79.5%, objectively measured physical activity 9.1%, intake of fruits 66.7%, vegetables 38.4%, fish 96.8%, saturated fat 25.4%, fiber 29.5%, and alcohol 78.5%, use of antidiabetics 84.3%, lipid-lowering drugs 86.8%, antihypertensives 78.5% and antithrombotics 77.9%. In total, 0.8% achieved all cardiovascular risk factor targets (blood pressure, LDL cholesterol, BMI and waist circumference combined). Compared to men, a lower proportion of women achieved the target for waist circumference (6.9% vs 18.1%, p = 0.002). Compared to participants 65 years or older, a higher proportion of those 40-64 years achieved the target for blood pressure (71.2% vs 49.0%, p < 0.001), and a lower proportion achieved the target for BMI (15.3 vs 21.4, p = 0.007).

Conclusion

Secondary prevention after myocardial infarction was suboptimal in both women and men. A negligible proportion achieved the treatment target for all risk factors. Improvement in follow-up care after myocardial infarction is needed.

Update on cardiovascular prevention in clinical practice: A position paper of the European Association of Preventive Cardiology of the European Society of Cardiology

European guidelines on cardiovascular prevention in clinical practice were first published in 1994 and have been regularly updated, most recently in 2016, by the Sixth European Joint Task Force. Given the amount of new information that has become available since then, components from the task force and experts from the European Association of Preventive Cardiology of the European Society of Cardiology were invited to provide a summary and critical review of the most important new studies and evidence since the latest guidelines were published. The structure of the document follows that of the previous document and has six parts: Introduction (epidemiology and cost effectiveness); Cardiovascular risk; How to intervene at the population level; How to intervene at the individual level; Disease-specific interventions; and Settings: where to intervene? In fact, in keeping with the guidelines, greater emphasis has been put on a population-based approach and on disease-specific interventions, avoiding re-interpretation of information already and previously considered. Finally, the presence of several gaps in the knowledge is highlighted.

The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases

Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.