Validation Study of Cardiovascular International Statistical Classification of Diseases and Related Health Problems, Tenth Edition, Australian Modification (ICD-10-AM) Codes in Administrative Healthcare Databases (ANZACS-QI 77)

BACKGROUND

Administrative healthcare databases can be utilised for research. The accuracy of the International Statistical Classification of Diseases and Related Health Problems, Tenth Edition, Australian Modification (ICD-10-AM) coding of cardiovascular conditions in New Zealand is not known and requires validation.

METHOD

International Statistical Classification of Diseases and Related Health Problems, Tenth Edition, Australian Modification coded discharges for acute coronary syndrome (ACS), heart failure (HF) and atrial fibrillation (AF), in both primary and secondary diagnostic positions, were identified from four district health boards between 1 January 2019 and 31 June 2019. A sample was randomly selected for retrospective clinician review for evidence of the coded diagnosis according to contemporary diagnostic criteria. Positive predictive values (PPVs) for ICD-10-AM coding vs clinician review were calculated. This study is also known as All of New Zealand, Acute Coronary Syndrome-Quality Improvement (ANZACS-QI) 77.

RESULTS

A total of 600 cases (200 for each diagnosis, 5.0% of total identified cases) were reviewed. The PPV of ACS was 93% (95% confidence interval [CI] 89%-96%), HF was 93% (95% CI 89%-96%) and AF was 96% (95% CI 92%-98%). There were no differences in PPV between district health boards. PPV for ACS were lower in Māori vs non-Māori (72% vs 96%; p=0.004), discharge from non-Cardiology vs Cardiology services (89% vs 96%; p=0.048) and ICD-10-AM coding for unstable angina vs myocardial infarction (81% vs 95%; p=0.011). PPV for HF were higher in the primary vs secondary diagnostic position (100% vs 89%; p=0.001).

CONCLUSIONS

The PPVs of ICD-10-AM coding for ACS, HF, and AF were high in this validation study. ICD-10-AM coding can be used to identify these diagnoses in administrative databases for the purposes of healthcare evaluation and research.

Longitudinal NT-proBNP: Associations With Echocardiographic Changes and Outcomes in Heart Failure

BACKGROUND

The relationship of serial NT-proBNP (N-terminal pro-B-type natriuretic peptide) measurements with changes in cardiac features and outcomes in heart failure (HF) remains incompletely understood. We determined whether common clinical covariates impact these relationships.

METHODS AND RESULTS

In 2 nationwide observational populations with HF, the relationship of serial NT-proBNP measurements with serial echocardiographic parameters and outcomes was analyzed, further stratified by HF with reduced versus preserved left ventricular ejection fraction, inpatient versus outpatient enrollment, age, obesity, chronic kidney disease, atrial fibrillation, and attainment of ≥50% guideline-recommended doses of renin-angiotensin system inhibitors and β-blockers. Among 1911 patients (mean±SD age, 65.1±13.4 years; 26.6% women; 62% inpatient and 38% outpatient), NT-proBNP declined overall, with more rapid declines among inpatients, those with obesity, those with atrial fibrillation, and those attaining ≥50% guideline-recommended doses. Each doubling of NT-proBNP was associated with increases in left ventricular volume (by 6.1 mL), E/e' (transmitral to mitral annular early diastolic velocity ratio) (by 1.4 points), left atrial volume (by 3.6 mL), and reduced left ventricular ejection fraction (by -2.1%). The effect sizes of these associations were lower among patients with HF with preserved ejection fraction, atrial fibrillation, or advanced age (Pinteraction<0.001). A landmark analysis identified that an SD increase in NT-proBNP over 6 months was associated with a 27% increase in the risk of the composite event of HF hospitalization or all-cause death between 6 months and 2 years (adjusted hazard ratio, 1.27 [95% CI, 1.15-1.40]; P<0.001).

CONCLUSIONS

The relationships between NT-proBNP and structural/functional remodeling differed by age, presence of atrial fibrillation, and HF phenotypes. The association of increased NT-proBNP with increased risk of adverse outcomes was consistent in all subgroups.

Sex differences in outcomes after acute coronary syndrome vary with age: a New Zealand national study

AIMS

This study investigated age-specific sex differences in short- and long-term clinical outcomes following hospitalization for a first-time acute coronary syndrome (ACS) in New Zealand (NZ).

METHODS AND RESULTS

Using linked national health datasets, people admitted to hospital for a first-time ACS between January 2010 and December 2016 were included. Analyses were stratified by sex and 10-year age groups. Logistic and Cox regression were used to assess in-hospital death and from discharge the primary outcome of time to first cardiovascular (CV) readmission or death and other secondary outcomes at 30 days and 2 years. Among 63 245 people (mean age 69 years, 40% women), women were older than men at the time of the ACS admission (mean age 73 vs. 66 years), with a higher comorbidity burden. Overall compared with men, women experienced higher rates of unadjusted in-hospital death (10% vs. 7%), 30-day (16% vs. 12%) and 2-year (44% vs. 34%) death, or CV readmission (all P < 0.001). Age group-specific analyses showed sex differences in outcomes varied with age, with younger women (<65 years) at higher risk than men and older women (≥85 years) at lower risk than men: unadjusted hazard ratio of 2-year death or CV readmission for women aged 18-44 years = 1.51 [95% confidence interval (CI) 1.21-1.84] and aged ≥85 years = 0.88 (95% CI 0.83-0.93). The increased risk for younger women was no longer significant after multivariable adjustment whereas the increased risk for older men remained.

CONCLUSION

Men and women admitted with first-time ACS have differing age and comorbidity profiles, resulting in contrasting age-specific sex differences in the risk of adverse outcomes between the youngest and oldest age groups.

The Prevalence and Management of Atrial Fibrillation in New Zealand Māori Detected through an Abdominal Aortic Aneurysm Screening Program

BACKGROUND

Atrial fibrillation (AF) screening was incorporated into an abdominal aortic aneurysm screening (AAA) program for New Zealand (NZ) Māori.

METHODS

AF screening was performed as an adjunct to AAA screening of Māori men aged 60-74 years and women aged 65-74 years registered with primary health care practices in Auckland, NZ. Pre-existing AF was determined through coded diagnoses or medications in the participant's primary care record. Subsequent audit of the record assessed accuracy of pre-screening coding, medication use and clinical follow-up.

RESULTS

Among 1,933 people successfully screened, the prevalence of AF was 144 (7.4%), of which 46 (2.4% of the cohort) were patients without AF coded in the medical record. More than half of these were revealed to be known AF but that was not coded. Thus, the true prevalence of newly detected AF was 1.1% (n=21). An additional 48 (2.5%) of the cohort had been coded as AF but were not in AF at the time of screening. Among the 19 at-risk screen-detected people with AF, 10 started appropriate anticoagulation therapy within 6 months. Of the nine patients who did not commence anticoagulation therapy, five had a subsequent adverse clinical outcome in the follow-up period, including one with ischaemic stroke; two had contraindications to anticoagulants. Among those with previously diagnosed AF, the proportion receiving anticoagulation therapy rose from 57% pre-screening to 83% at 6 months post-screening (p<0.0001); among newly diagnosed AF the proportion rose from 0% to 53% (p<0.01).

CONCLUSIONS

AF screening is a feasible low-cost adjunct to AAA screening with potential to reduce ethnic inequities in stroke incidence. However, effective measures are needed to ensure that high-risk newly diagnosed AF is managed according to best practice guidelines.

Development and validation of cardiovascular risk prediction equations in 76 000 people with known cardiovascular disease

AIMS

Multiple health administrative databases can be individually linked in Aotearoa New Zealand, using encrypted identifiers. These databases were used to develop cardiovascular risk prediction equations for patients with known cardiovascular disease (CVD).

METHODS AND RESULTS

Administrative health databases were linked to identify all people aged 18-84 years with known CVD, living in Auckland and Northland, Aotearoa New Zealand, on 1 January 2014. The cohort was followed until study outcome, death, or 5 years. The study outcome was death or hospitalization due to ischaemic heart disease, stroke, heart failure, or peripheral vascular disease. Sex-specific 5-year CVD risk prediction equations were developed using multivariable Fine and Gray models. A total of 43 862 men {median age: 67 years [interquartile range (IQR): 59-75]} and 32 724 women [median age: 70 years (IQR: 60-77)] had 14 252 and 9551 cardiovascular events, respectively. Equations were well calibrated with good discrimination. Increasing age and deprivation, recent cardiovascular hospitalization, Mori ethnicity, smoking history, heart failure, diabetes, chronic renal disease, atrial fibrillation, use of blood pressure lowering and anti-thrombotic drugs, haemoglobin A1c, total cholesterol/HDL cholesterol, and creatinine were statistically significant independent predictors of the study outcome. Fourteen per cent of men and 23% of women had predicted 5-year cardiovascular risk <15%, while 28 and 24% had ≥40% risk.

CONCLUSION

Robust cardiovascular risk prediction equations were developed from linked routine health databases, a currently underutilized resource worldwide. The marked heterogeneity demonstrated in predicted risk suggests that preventive therapy in people with known CVD would be better informed by risk stratification beyond a one-size-fits-all high-risk categorization.

A Risk Model to Predict Statin Non-Adherence Following an Acute Coronary Syndrome

BACKGROUND

Patients at risk of statin non-adherence are often not identified during hospital admission with an acute coronary syndrome (ACS).

METHODS

In 19,942 patients hospitalised for ACS, statin dispensing was determined from the national pharmaceutical dispensing database. A risk score for non-adherence was developed from a multivariable Poisson regression model of associations between risk factors and the statin Medication Possession Ratio (MPR) <0.8 6-18 months after hospital discharge.

RESULTS

Statin MPR was <0.8 in 4,736 (24%) patients. MPR <0.8 was more likely in patients with a history of cardiovascular disease (CVD) (RR 3.79, CI 95% 3.42-4.20) and those without known CVD (RR 2.25, 95% CI 2.04-2.48) who were not taking a statin on ACS admission, compared to patients with low density lipoprotein (LDL) cholesterol <2 mmol/L who were on a statin. For patients taking a statin on admission, higher LDL was associated with MPR <0.8 (≥3 versus <2 mmol/L, RR 1.96, 95%CI 1.72-2.24). Other independent risk factors for MPR <0.8 were age <45 years, female, disadvantaged ethnic groups, and no coronary revascularisation during the ACS admission. The risk score, which included nine variables, had a C-statistic of 0.67. MPR was <0.8 in 12% of 5,348 patients with a score ≤5 (lowest quartile) and 45% of 5,858 patients with a score ≥11 (highest quartile).

CONCLUSION

A risk score generated from routinely collected data predicts statin non-adherence in patients hospitalised with ACS. This may be used to target inpatient and outpatient interventions to improve medication adherence.

Prognostic modelling of clinical outcomes after first-time acute coronary syndrome in New Zealand

OBJECTIVE

The Multi-Ethnic New Zealand Study of Acute Coronary Syndromes (MENZACS) was established to investigate the drivers of secondary events after first-time acute coronary syndrome (ACS), including addressing inequitable outcomes by ethnicity. Herein, the first clinical outcomes and prognostic modelling approach are reported.

METHODS

First, in 28 176 New Zealanders with first-time ACS from a national registry, a clinical summary score for predicting 1-year death/cardiovascular readmission was created using Cox regression of 20 clinical variables. This score was then calculated in the 2015 participant MENZACS study to represent clinical risk. In MENZACS, Cox regression was used to assess N-terminal pro-B-type natriuretic peptide (NT-proBNP) as a prognostic marker for death/cardiovascular readmission in four models, adjusting for (1) age and sex; (2) age, sex, ethnicity; (3) clinical summary score; (4) clinical summary score and ethnicity.

RESULTS

Of the 2015 MENZACS participants (mean age 61 years, 79% male, 73% European, 14% Māori, 5% Pacific people), 2003 were alive at discharge. Of the 2003, 416 (20.8%) experienced all-cause death/cardiovascular readmission over a median of 3.5 years. In a simple model, age, male sex, Māori ethnicity and NT-proBNP levels were significant predictors of outcome. After adjustment for the clinical summary score, which includes age and sex, NT-proBNP and ethnicity were no longer statistically significant: log₂(NT-proBNP) hazard ratio (HR) 1.03, 95% confidence interval (95% CI) 0.98 to 1.08, p=0.305; Māori ethnicity HR 1.26, 95% CI 0.97 to 1.62, p=0.084.

CONCLUSIONS

In 2015 patients with first-time ACS, recurrent events were common (20.8%). Increasing NT-proBNP levels and Māori ethnicity were predictors of death/cardiovascular readmission, but not after adjustment for the 20 clinical risk factors represented by the clinical summary score.

TRIAL REGISTRATION NUMBER

ACTRN12615000676516.

Guideline-Directed Medical Therapy Before and After Primary Prevention Implantable Cardioverter Defibrillator Implantation in New Zealand (ANZACS-QI 66)

INTRODUCTION

Guidelines recommend angiotensin converting enzyme inhibitors (ACEi)/angiotensin receptor blockers (ARB)/angiotensin receptor neprilysin inhibitors (ARNI); beta blockers; and mineralocorticoid receptor antagonists (MRA) in patients with symptomatic heart failure and reduced left ventricular ejection fraction before consideration of primary prevention implantable cardioverter defibrillator (ICD). This study aims to investigate dispensing rates of guideline-directed medical therapy (GDMT) before and after primary prevention ICD implantation in New Zealand.

METHODS

All patients receiving a primary prevention ICD between 2009 and 2018 were identified using nationally collected data on all public hospital admissions in New Zealand. This was anonymously linked to national pharmaceutical data to obtain medication dispensing. Medications were categorised as low dose (<50% of target dose), 50-99% of target dose or target dose based on international guidelines.

RESULTS

Of the 1,698 patients identified, ACEi/ARB/ARNI, beta blockers and MRA were dispensed in 80.2%, 83.6% and 45.4%, respectively, prior to ICD implant. However, ≥50% target doses of each medication class were dispensed in only 51.8%, 51.8% and 34.5%, respectively. Only 15.8% of patients were receiving ≥50% target doses of all three classes of medications. In the 1,666 patients who survived 1 year after ICD implant, the proportions of patients dispensed each class of medications remained largely unchanged.

CONCLUSION

Dispensing of GDMT was suboptimal in patients before and after primary prevention ICD implantation in New Zealand, and only a minority received ≥50% target doses of all classes of medication. Interventions are needed to optimise use of these standard evidence-based medications to improve clinical outcomes and avoid unnecessary device implantation.

Cardiovascular risk prediction in healthy older people

Identification of individuals with increased risk of major adverse cardiovascular events (MACE) is important. However, algorithms specific to the elderly are lacking. Data were analysed from a randomised trial involving 18,548 participants ≥ 70 years old (mean age 75.4 years), without prior cardiovascular disease events, dementia or physical disability. MACE included coronary heart disease death, fatal or nonfatal ischaemic stroke or myocardial infarction. Potential predictors tested were based on prior evidence and using a machine-learning approach. Cox regression analyses were used to calculate 5-year predicted risk, and discrimination evaluated from receiver operating characteristic curves. Calibration was also assessed, and the findings internally validated using bootstrapping. External validation was performed in 25,138 healthy, elderly individuals in the primary care environment. During median follow-up of 4.7 years, 594 MACE occurred. Predictors in the final model included age, sex, smoking, systolic blood pressure, high-density lipoprotein cholesterol (HDL-c), non-HDL-c, serum creatinine, diabetes and intake of antihypertensive agents. With variable selection based on machine-learning, age, sex and creatinine were the most important predictors. The final model resulted in an area under the curve (AUC) of 68.1 (95% confidence intervals 65.9; 70.4). The model had an AUC of 67.5 in internal and 64.2 in external validation. The model rank-ordered risk well but underestimated absolute risk in the external validation cohort. A model predicting incident MACE in healthy, elderly individuals includes well-recognised, potentially reversible risk factors and notably, renal function. Calibration would be necessary when used in other populations.

Ethnic variation in the trends of new implantable cardioverter defibrillator implants in New Zealand 2005-2019 (ANZACS-QI 63)

AIMS

Ethnic variation in implantable cardioverter defibrillator (ICD) implant rates have been reported internationally but have not previously been examined in New Zealand. This study examined trends in new ICD implants by ethnicity over an extended period.

METHODS

All patients who received a new ICD implant between 2005 and 2019 were identified using the National Minimum Dataset, which collects information on all public hospital admissions in New Zealand. Ethnicity was classified using the following standard prioritisation: Māori, Pacific, Asian and European/Other. New ICD implant rates were analysed by ethnicity and age groups.

RESULTS

A total of 5,514 new ICDs were implanted. New ICD implant rates increased from 41.4/million in 2005 to 98.2/million in 2019, an average increase of 5.4%/year (p<0.01). The highest age-standardised implant rates were among Māori, followed by Pacific, European/Other and Asian ethnicities. The largest increase was seen in Pacific people at 8.9%/year (p<0.01), followed by Māori and Asian people at 4.7%/year and 4.3%/year respectively (both p<0.01). In European/Other patients, ICD implant rates increased by 10.3%/year (p<0.01) between 2005 to 2012, then plateaued at -0.4%/year (p=0.71) between 2012 to 2019. By 2019, the age-standardised implant rates in Māori and Pacific people were two-fold higher than European/Others.

CONCLUSION

There is marked ethnic variation in ICD implant rates in New Zealand. The higher implant rates in Māori and Pacific parallel known ethnic differences in rates of underlying cardiac disease. The more rapid increase in implant rates in these ethnic groups may represent more equitable treatment over time.

The importance of considering both primary and secondary diagnostic codes when using administrative health data to study acute coronary syndrome epidemiology (ANZACS-QI 47)

AIMS

Routinely collected health administrative data have become an important data source for investigators assessing disease epidemiology. Our aim was to investigate the implications of identifying acute coronary syndrome (ACS) events in New Zealand (NZ) national hospitalization data using either the first (primary) or subsequent (secondary) codes.

METHODS AND RESULTS

Using national health datasets, we identified all NZ hospitalizations (2014-16) for patients ≥20 years with a primary or secondary International Classification of Diseases 10th Revision, Australian Modification (ICD10-AM) ACS code. Outcomes included 1-year all-cause and cause-specific mortality, hospitalized non-fatal myocardial infarction, heart failure, stroke, or major bleeding, and a composite comprising these outcomes. Of 35 646 ACS hospitalizations, 78.5% were primary and 21.5% secondary diagnoses. Compared to primary coding, patients with a secondary diagnosis were older (mean 77 vs. 69 years), more likely to be females (48% vs. 36%), had more comorbidity, and were less likely to receive coronary angiography or revascularization. Higher adverse event rates were observed for the secondary diagnosis group including a three-fold higher 1-year mortality (40% vs. 13%) and two-fold higher composite adverse outcome (54% vs. 26%). The use of primary codes alone, rather than combined primary and secondary codes, resulted in overestimation of coronary angiography and revascularization rates, and underestimation of the 1-year case fatality (13.1% vs. 19.0%) and composite adverse event rate (26% vs. 32%).

CONCLUSION

Patient characteristics and outcomes of ACS events recorded as primary vs. secondary codes are very different. These findings have important implications for designing studies utilizing ICD10-AM codes.

Acute coronary syndrome registry enrolment status: differences in patient characteristics and outcomes and implications for registry data use (ANZACS-QI 36)

AIMS

Clinical registry-derived data are widely used to represent patient populations. In New Zealand (NZ), a national registry-the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry-aims to include all patients undergoing coronary angiography; other acute coronary syndrome (ACS) patients are also registered but without complete capture. This study compares national hospitalization data of all first-time ACS admissions in NZ with patients in the ANZACS-QI registry, to investigate the use of clinical registry-derived data in research and in assessing clinical care.

METHODS AND RESULTS

Patients admitted with first-time ACS in the NZ National Hospitalisation Dataset between 1 January 2015 and 31 December 2016 were included. Clinical characteristics and time to 12-month clinical outcomes were compared between patients captured and not-captured in the registry. A total of 16 569 patients were admitted with first-time ACS, median age 69 years, 61% male; 60% (n = 9918) were enrolled in ANZACS-QI. Registry-captured patients were younger, more often male, and with a lower comorbidity burden than non-captured patients. Overall, 16% patients died within 12 months, 15% experienced a non-fatal cardiovascular (CV) readmission, and 28% either died or were readmitted. Patients not captured in the registry were more than twice as likely to have experienced death or a non-fatal CV readmission within 12 months as captured patients.

CONCLUSIONS

First-time ACS patients captured in the ANZACS-QI registry had very different clinical characteristics and outcomes than those not captured. Cardiovascular registry-derived data are dependent on registry design and may not be representative of the wider patient population; this must be considered when using registry-derived data.

Regional variation in cardiac implantable electronic device implants trends in New Zealand over the past decade (ANZACS-QI 54)

BACKGROUND

Permanent pacemaker (PPM) and implantable cardioverter defibrillator (ICD) implant rates have increased in New Zealand over the past decade. This study aims to provide a contemporary analysis of regional variation in implant rates.

METHOD

New PPM and ICD implants in patients ≥15 years were identified for ten years (2009 to 2018) using procedure coding in the National Minimum Datasets, which collects all New Zealand public hospital admissions. Age-standardised new implant rates per million adult population were calculated for each of the four regions (Northern, Midland, Central and Southern) and the 20 district health boards (DHBs) across those regions. Trend analysis was performed using joinpoint regression.

RESULTS

New PPM implant rates increased nationally by 3.4%/year (p < 0.001). The Northern region had the highest new PPM implant rate, increasing by 4.5%/year (p < 0.001). Excluding DHBs with <50 000 people, the new PPM implant rate for 2017/2018 was highest in Counties Manukau DHB (854.3/million, 95% CI: 774.9-933.6/million) and lowest in Canterbury DHB (488.6/million, 95% CI: 438.1-539.0/million). New ICD implant rates increased nationally by 3.0%/year (p = 0.002). The Midland region had the highest new ICD implant rate, increasing by 3.8%/year (p = 0.013). Excluding DHBs with <50 000 people, the new ICD implant rate for 2017/2018 was highest in Bay of Plenty DHB (228.5/million, 95% CI: 180.4-276.6/million) and lowest in Canterbury DHB (90.2/million, 95% CI: 69.9-110.4/million).

CONCLUSION

There was significant variation in PPM and ICD implant rates across regions and DHBs, suggesting potential inequity in patient access across New Zealand. This article is protected by copyright. All rights reserved.

Outcomes for working age patients after first-time acute coronary syndrome - ANZACS-QI 35

BACKGROUND

Acute coronary syndrome (ACS) events and the ongoing burden of disease can have a significant impact on the subsequent life-course of working age people.

METHODS

We report 12-month clinical outcomes for 10,822 patients hospitalized with first-time ACS between 2015-2016 and enrolled in the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry, with a focus on people of working age (defined as <65 years).

RESULTS

Nearly half (48%) of first-time ACS occurred in people of working age. Compared to those >65 years, these patients had a high burden of cardiovascular risk factors, and were more likely to be male (75% vs 60%), to be of non-European ethnicity (36% vs 15%), and to be living in areas of high deprivation. Subsequent clinical events were common in the younger patients, with 15% dying or being readmitted for cardiovascular causes within 12 months despite high rates of angiography (96%), revascularization (74%) and evidence-based medical therapy at the time of the index ACS event.

CONCLUSIONS

The high risk factor burden and subsequent high rate of clinical events in working age patients reinforces the need for a longer-term focus on strategies to improve clinical outcomes following first-time ACS.

Ten-year trends in cardiac implantable electronic devices in New Zealand: a national data linkage study (ANZACS-QI 51)

BACKGROUND

Implant rates for cardiac implantable electronic devices (CIED), including permanent pacemakers (PPM) and implantable cardioverter defibrillators (ICD), have increased globally in recent decades.

AIMS

This is the first national study providing a contemporary analysis of national CIED implant trends by sex-specific age groups over an extended period.

METHODS

Patient characteristics and device type were identified for 10 years (2009-2018) using procedure coding in the National Minimum Datasets, which collects all New Zealand (NZ) public hospital admissions. CIED implant rates represent implants/million population.

RESULTS

New PPM implant rates increased by 4.6%/year (P < 0.001), increasing in all age groups except patients <40 years. Males received 60.1% of new PPM implants, with higher implant rates across all age groups compared with females. The annual increase in age-standardised implant rates was similar for males and females (3.4% vs 3.0%; P = 0.4). By 2018 the overall PPM implant rate was 538/million. New ICD implant rates increased by 4.2%/year (P < 0.001), increasing in all age groups except patients <40 and ≥ 80 years. Males received 78.1% of new ICD implants, with higher implant rates across all age groups compared to females. The annual increase in age-standardised implant rates was higher in males compared with females (3.5% vs 0.7%; P < 0.001). By 2018 the overall ICD implant rate was 144/million.

CONCLUSION

CIED implant rates have increased steadily in NZ over the past decade but remain low compared with international benchmarks. Males had substantially higher CIED implant rates compared with females, with a growing gender disparity in ICD implant rates.

Predicting cardiovascular disease risk across the atherosclerotic disease continuum

AIMS

Cardiovascular disease (CVD) guidelines dichotomize populations into primary and secondary prevention. We sought to develop a risk equation for secondary prevention of CVD that complements existing equations for primary prevention of CVD, and to describe the distributions of CVD risk across the population.

METHODS AND RESULTS

Adults aged 30-79 years who had routine CVD risk assessment in 2007-16 were identified from a large primary care cohort (PREDICT) with linkage to national and regional datasets. The 5-year risk of developing CVD among people without atherosclerotic CVD (ASCVD) was calculated using published equations (PREDICT-1°). A new risk equation (PREDICT-2°) was developed from Cox regression models to estimate the 5-year risk of CVD event recurrence among patients with known ASCVD. The outcome for both equations was hospitalization for a CVD event or cardiovascular death. Of the 475 161 patients, 12% (57 061) had ASCVD. For those without ASCVD, median (interquartile range) 5-year risks with the PREDICT-1° score were women 2.2% (1.2-4.2%), men 3.5% (2.0-6.6%), and whole group 2.9% (1.6-5.5%). For those with ASCVD, the 5-year risks with the new PREDICT-2° equation were women 21% (15-33%), men 23% (16-35%), and whole group 22% (16-34%).

CONCLUSION

We developed CVD risk scores for people with ASCVD (PREDICT-2°) to complement the PREDICT-1° scores. Median CVD risk is eight-fold higher among those with ASCVD than those without; however, there was overlap and the widest distribution of CVD risk was among people with ASCVD. This study describes a CVD risk continuum and the limitations of a 'one size fits all' approach to assessing risk in people with ASCVD.

Development and validation of a cardiovascular risk score for patients in the community after acute coronary syndrome

OBJECTIVE

Following acute coronary syndrome (ACS), patients are managed long-term in the community, yet few tools are available to guide patient-clinician communication about risk management in that setting. We developed a score for predicting cardiovascular disease (CVD) risk among patients managed in the community after ACS.

METHODS

Adults aged 30-79 years with prior ACS were identified from a New Zealand primary care CVD risk management database (PREDICT) with linkage to national mortality, hospitalisation, pharmaceutical dispensing and regional laboratory data. A Cox model incorporating clinically relevant factors was developed to estimate the time to a subsequent fatal or non-fatal CVD event and transformed into a 5-year risk score. External validation was performed in patients (Coronary Disease Cohort Study) assessed 4 months post-ACS.

RESULTS

The PREDICT-ACS cohort included 13 703 patients with prior hospitalisation for ACS (median 1.9 years prior), 69% men, 58% European, median age 63 years, who experienced 3142 CVD events in the subsequent 5 years. Median estimated 5 year CVD risk was 24% (IQR 17%-35%). The validation cohort consisted of 2014 patients, 72% men, 92% European, median age 67 years, with 712 CVD events in the subsequent 5 years. Median estimated 5-year risk was 33% (IQR 24%-51%). The risk score was well calibrated in the derivation and validation cohorts, and Harrell's c-statistic was 0.69 and 0.68, respectively.

CONCLUSIONS

The PREDICT-ACS risk score uses data routinely available in community care to predict the risk of recurrent clinical events. It was derived and validated in real-world contemporary populations and can inform management decisions with patients living in the community after experiencing an ACS.

Validation of clinical prediction models: what does the "calibration slope" really measure?

BACKGROUND AND OBJECTIVES

Definitions of calibration, an aspect of model validation, have evolved over time. We examine use and interpretation of the statistic currently referred to as the calibration slope.

METHODS

The history of the term "calibration slope", and usage in papers published in 2016 and 2017, were reviewed. The behaviour of the slope in illustrative hypothetical examples and in two examples in the clinical literature was demonstrated.

RESULTS

The paper in which the statistic was proposed described it as a measure of "spread" and did not use the term "calibration". In illustrative examples, slope of 1 can be associated with good or bad calibration, and this holds true across different definitions of calibration. In data extracted from a previous study, the slope was correlated with discrimination, not overall calibration. Many authors of recent papers interpret the slope as a measure of calibration; a minority interpret it as a measure of discrimination or do not explicitly categorise it as either. Seventeen of thirty-three papers used the slope as the sole measure of calibration.

CONCLUSION

Misunderstanding about this statistic has led to many papers in which it is the sole measure of calibration, which should be discouraged.

Outcome after myocardial infarction without obstructive coronary artery disease

OBJECTIVE

The medium-term outcome and cause of death in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA) is not well characterised. The aim of this study was to compare mortality and rates of recurrent events in post myocardial infarction (MI) patients with obstructive coronary artery disease (CAD) and in patients with MINOCA compared with an age and sex-matched cohort without cardiovascular disease (CVD).

METHODS

We performed a national cohort study of consecutive patients undergoing coronary angiography for MI during 2 years between 2013 and 2015 from the All New Zealand Acute Coronary Syndrome-Quality Improvement (ANZACS QI) registry. MI patient registry data were linked anonymously to national hospitalisation and mortality records. Age and sex matched patients without known CVD formed the comparison group.

RESULTS

Of the 8305 patients with MI, 897 (10.8%) were classified as MINOCA. Compared with those without known CVD, the adjusted HRs for the primary outcome (all-cause death or recurrent non-fatal MI) were 7.81 (95% CI 6.64 to 9.19, p<0.0001) in those with obstructive CAD and 4.64 (95% CI 3.54 to 6.10, p<0.0001) in those with MINOCA. Kaplan-Meier all-cause mortality at 2 years was 7.9% for those with obstructive CAD, with nearly half being CVD deaths (3.6% CVD deaths and 4.5% non-CVD deaths, respectively). In contrast, MINOCA all-cause mortality was 4.9% with non-CVD death (4.5%) predominating.

CONCLUSIONS

MINOCA is common and has an adverse outcome rate approximately half than that of those with obstructive CAD. The predominant contributor to mortality is non-CVD death. The rate of events in MINOCA is significantly greater than the population without CVD.

Developing and validating a cardiovascular risk score for patients in the community with prior cardiovascular disease

OBJECTIVE

Patients with atherosclerotic cardiovascular disease (CVD) vary significantly in their risk of future CVD events; yet few clinical scores are available to aid assessment of risk. We sought to develop a score for use in primary care that estimates short-term CVD risk in these patients.

METHODS

Adults aged <80 years with prior CVD were identified from a New Zealand primary care cohort study (PREDICT), and linked to national mortality, hospitalisation and dispensing databases. A Cox model with an outcome of myocardial infarction, stroke or CVD death within 2 years was developed. External validation was performed in a cohort from the UK.

RESULTS

24 927 patients, 63% men, 63% European, median age 65 years (IQR 58-72 years), experienced 1480 CVD events within 2 years after a CVD risk assessment. A risk score including ethnicity, comorbidities, body mass index, creatine creatinine and treatment, in addition to established risk factors used in primary prevention, predicted a median 2-year CVD risk of 5.0% (IQR 3.5%-8.3%). A plot of actual against predicted event rates showed very good calibration throughout the risk range. The score performed well in the UK cohort but overestimated risk for those at highest risk, who were predominantly patients defined as having heart failure.

CONCLUSIONS

The PREDICT-CVD secondary prevention score uses routine measurements from clinical practice that enable it to be implemented in a primary care setting. The score will facilitate risk communication between primary care practitioners and patients with prior CVD, particularly as a resource to show the benefit of risk factor modification.

A new approach to assessment of the left ventricle

Cardiac motion is a continuous process; however most measurements to assess cardiac function are taken at brief moments in the cardiac cycle. Using functional data analysis, repeated measurements of left ventricular volume recorded at each frame of a continuous image measured with cardiac ultrasound (echocardiography) were turned into a function of volume over time. The first derivative of the displacement of volume with respect to time is velocity; the second derivative is acceleration. Plotting volume, velocity, and acceleration against each other in a 3-dimensional plot results in a closed loop. The area within the loop is defined by the kinematics of volume change and so may represent ventricular function.

•

We have developed an approach to analyzing images of the left ventricle that incorporates information from throughout the cardiac cycle.

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Comparing systolic and diastolic areas within a loop defined by volume, velocity, and acceleration of left ventricular volume highlights imbalances in the kinematics of the two phases, potentially indicating early sub-clinical disease.

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Substantially more information about left ventricular function may be derived from a non-invasive clinically available tool such as echocardiography.

Is heart rate a risk marker in patients with chronic heart failure and concomitant atrial fibrillation? Results from the MAGGIC meta-analysis

AIM

To investigate the relationship between heart rate and survival in patients with heart failure (HF) and coexisting atrial fibrillation (AF).

METHODS AND RESULTS

Patients with AF included in the Meta-analysis Global Group in Chronic Heart Failure (MAGGIC) meta-analysis were the main focus of this analysis (3259 patients from 17 studies). The outcome was all-cause mortality at 3 years. Heart rate was analysed as a categorical (tertiles; T1 ≤77 b.p.m., T2 78-98 b.p.m., T3 ≥98 b.p.m.) and continuous variable. Cox proportional hazard models were used to compare the risk of all-cause death between tertiles of baseline heart rate. Patients in the highest tertile were more often female, less likely to have an ischaemic aetiology or diabetes, had a lower ejection fraction but higher blood pressure and New York Heart Association (NYHA) class. Higher heart rate was associated with higher mortality in patients with sinus rhythm (SR) but not in those in AF. In patients with heart failure and reduced ejection fraction (HF-REF) and AF, death rates per 100 patient years were lowest in the highest heart rate tertile (T1 18.9 vs. T3 15.9) but this difference was not statistically significant (P = 0.10). In patients with heart failure and preserved ejection fraction (HF-PEF), death rates per 100 patient years were highest in the highest heart rate tertile (T1 14.6 vs. T3 16.0, P = 0.014). However, after adjustment for other important prognostic variables, higher heart rate was no longer associated with higher mortality in HF-PEF (or HF-REF).

CONCLUSIONS

In this meta-analysis of patients with HF, heart rate does not have the same prognostic significance in patients in AF as it does in those in SR, irrespective of ejection fraction or treatment with beta-blocker.

Genetic markers of repolarization and arrhythmic events after acute coronary syndromes

BACKGROUND

There is a genetic contribution to the risk of ventricular arrhythmias in survivors of acute coronary syndromes (ACS). We wished to explore the role of 33 candidate single nucleotide polymorphisms (SNPs) in prolonged repolarization and sudden death in patients surviving ACS.

METHODS

A total of 2,139 patients (1680 white ethnicity) surviving an admission for ACS were enrolled in the prospective Coronary Disease Cohort Study. Extensive clinical, echocardiographic, and neurohormonal data were collected for 12 months, and clinical events were recorded for a median of 5 years. Each SNP was assessed for association with sudden cardiac death (SCD)/cardiac arrest (CA) and prolonged repolarization at 3 time-points: index admission, 1 month, and 12 months postdischarge.

RESULTS

One hundred six SCD/CA events occurred during follow-up (6.3%). Three SNPs from 3 genes (rs17779747 [KCNJ2], rs876188 [C14orf64], rs3864180 [GPC5]) were significantly associated with SCD/CA in multivariable models (after correction for multiple testing); the minor allele of rs17779747 with a decreased risk (hazard ratio [HR] 0.68 per copy of the minor allele, 95% CI 0.50-0.92, P = .012), and rs876188 and rs386418 with an increased risk (HR 1.52 [95% CI 1.10-2.09, P = .011] and HR 1.34 [95% CI 1.04-1.82, P = .023], respectively). At 12 months postdischarge, rs10494366 and rs12143842 (NOS1AP) were significant predictors of prolonged repolarization (HR 1.32 [95% CI 1.04-1.67, P = .022] and HR 1.30 [95% CI 1.01-1.66, P = .038], respectively), but not at earlier time-points.

CONCLUSION

Three SNPs were associated with SCD/CA. Repolarization time was associated with variation in the NOS1AP gene. This study demonstrates a possible role for SNPs in risk stratification for arrhythmic events after ACS.

Measurement and Data Transmission Validity of a Multi-Biosensor System for Real-Time Remote Exercise Monitoring Among Cardiac Patients

BACKGROUND

Remote telemonitoring holds great potential to augment management of patients with coronary heart disease (CHD) and atrial fibrillation (AF) by enabling regular physiological monitoring during physical activity. Remote physiological monitoring may improve home and community exercise-based cardiac rehabilitation (exCR) programs and could improve assessment of the impact and management of pharmacological interventions for heart rate control in individuals with AF.

OBJECTIVE

Our aim was to evaluate the measurement validity and data transmission reliability of a remote telemonitoring system comprising a wireless multi-parameter physiological sensor, custom mobile app, and middleware platform, among individuals in sinus rhythm and AF.

METHODS

Participants in sinus rhythm and with AF undertook simulated daily activities, low, moderate, and/or high intensity exercise. Remote monitoring system heart rate and respiratory rate were compared to reference measures (12-lead ECG and indirect calorimeter). Wireless data transmission loss was calculated between the sensor, mobile app, and remote Internet server.

RESULTS

Median heart rate (-0.30 to 1.10 b∙min-1) and respiratory rate (-1.25 to 0.39 br∙min-1) measurement biases were small, yet statistically significant (all P≤.003) due to the large number of observations. Measurement reliability was generally excellent (rho=.87-.97, all P<.001; intraclass correlation coefficient [ICC]=.94-.98, all P<.001; coefficient of variation [CV]=2.24-7.94%), although respiratory rate measurement reliability was poor among AF participants (rho=.43, P<.001; ICC=.55, P<.001; CV=16.61%). Data loss was minimal (<5%) when all system components were active; however, instability of the network hosting the remote data capture server resulted in data loss at the remote Internet server during some trials.

CONCLUSIONS

System validity was sufficient for remote monitoring of heart and respiratory rates across a range of exercise intensities. Remote exercise monitoring has potential to augment current exCR and heart rate control management approaches by enabling the provision of individually tailored care to individuals outside traditional clinical environments.

The development and feasibility of a composite score of echocardiographic indices that may stratify outcome in patients with diabetes mellitus

BACKGROUND

Early detection of changes in cardiac structure and function associated with type 2 diabetes (T2DM) is important. However when multiple abnormalities are present, combining individual measurements can be subjective. This study sought to create a simple echo score that summarises measurements that may detect early and prognostically important changes in cardiac function.

METHODS

Standard echocardiography was performed on 849 people with T2DM (median age 65years, 40% female, median duration of diabetes 5.5years). Principal components analysis was performed on measurements of LV mass, LA volume, E:e', and s', to create an objective summary score. The score was included in two Cox proportional hazard models adjusted for CV risk factors: one estimated the development of heart failure (HF) and the second estimated any CV event.

RESULTS

The first two principal components represented 75% of the variation between the four echo measurements. A continuous score that represents the residual difference between these two components was derived that only requires measurement of medial E:e' and s'. The score was significantly associated with the development of HF within four years (hazard ratio 1.34; 95% CI 1.15, 1.56).

CONCLUSIONS

We have developed a simple, objective score that enhances the use of echocardiography in the detection of sub-clinical cardiac disease in people with T2DM. Initial findings suggest that it may help identify those at increased risk of developing HF within four years.

Differing prognostic value of pulse pressure in patients with heart failure with reduced or preserved ejection fraction: results from the MAGGIC individual patient meta-analysis

AIMS

Low pulse pressure is a marker of adverse outcome in patients with heart failure (HF) and reduced ejection fraction (HF-REF) but the prognostic value of pulse pressure in patients with HF and preserved ejection fraction (HF-PEF) is unknown. We examined the prognostic value of pulse pressure in patients with HF-PEF [ejection fraction (EF) ≥ 50%] and HF-REF.

METHODS AND RESULTS

Data from 22 HF studies were examined. Preserved left ventricular ejection fraction (LVEF) was defined as LVEF ≥ 50%. All-cause mortality at 3 years was evaluated in 27 046 patients: 22 038 with HF-REF (4980 deaths) and 5008 with HF-PEF (828 deaths). Pulse pressure was analysed in quintiles in a multivariable model adjusted for the previously reported Meta-Analysis Global Group in Chronic Heart Failure prognostic variables. Heart failure and reduced ejection fraction patients in the lowest pulse pressure quintile had the highest crude and adjusted mortality risk (adjusted hazard ratio 1.68, 95% confidence interval 1.53-1.84) compared with all other pulse pressure groups. For patients with HF-PEF, higher pulse pressure was associated with the highest crude mortality, a gradient that was eliminated after adjustment for other prognostic variables.

CONCLUSION

Lower pulse pressure (especially <53 mmHg) was an independent predictor of mortality in patients with HF-REF, particularly in those with an LVEF < 30% and systolic blood pressure <140 mmHg. Overall, this relationship between pulse pressure and outcome was not consistently observed among patients with HF-PEF.

The prognostic impact of diastolic dysfunction in patients with chronic heart failure and post-acute myocardial infarction: Can age-stratified E/A ratio alone predict survival?

OBJECTIVE

To determine the prognostic implications of diastolic filling grades and identify whether age-stratified E/A ratio alone can identify patients at high risk of death post-AMI and HF. We hypothesized that in response to ageing and pathology, a normal E/A (>1) could be considered abnormal in patients post-AMI older than 65years, and that in patients with symptomatic HF, a normal E/A always represents advanced diastolic dysfunction.

METHODS AND RESULTS

This is a sub-analysis of the Meta-analysis Research Group in Echocardiography (MeRGE) which combined individual patient data from 30 prospective studies and demonstrated that restrictive filling was an important and independent predictor of all-cause mortality. This sub-analysis is restricted to those studies in which continuous E/A data were available (20 studies) and includes a total of 3082 AMI and 2321 HF patients. Patients were classified at the time of echocardiography into four filling patterns: normal, abnormal relaxation, pseudonormal, and restrictive filling. Post-AMI patients were divided into four groups on the basis of age and E/A, while patients with HF were classified into three groups, based on only E/A. Mortality across groups was compared using Kaplan-Meier survival analysis and Cox proportional hazards. In multivariable analyses in the AMI patients, age-stratified E/A was an independent predictor of outcome (HR 1.43 (95% CI: 1.31-1.56)), and in the HF cohort, E/A was confirmed as an independent predictor of mortality (HR 1.12 (95% CI 1.09-1.16)) alongside age and ejection fraction.

CONCLUSIONS

Age-stratified E/A is an independent predictor of mortality after AMI and in HF patients, regardless of left ventricular ejection fraction, age and gender. E/A ratio could be a first step echocardiographic risk stratification, which could precede and indicate the need for more advanced diagnostic and prognostic considerations in high-risk AMI and HF patients.

Heart failure in younger patients: the Meta-analysis Global Group in Chronic Heart Failure (MAGGIC)

AIM

Our understanding of heart failure in younger patients is limited. The Meta-analysis Global Group in Chronic Heart Failure (MAGGIC) database, which consisted of 24 prospective observational studies and 7 randomized trials, was used to investigate the clinical characteristics, treatment, and outcomes of younger patients.

METHODS AND RESULTS

Patients were stratified into six age categories: <40 (n = 876), 40-49 (n = 2638), 50-59 (n = 6894), 60-69 (n = 12 071), 70-79 (n = 13 368), and ≥80 years (n = 6079). Of 41 926 patients, 2.1, 8.4, and 24.8% were younger than 40, 50, and 60 years of age, respectively. Comparing young (<40 years) against elderly (≥80 years), younger patients were more likely to be male (71 vs. 48%) and have idiopathic cardiomyopathy (63 vs. 7%). Younger patients reported better New York Heart Association functional class despite more severe left ventricular dysfunction (median ejection fraction: 31 vs. 42%, all P < 0.0001). Comorbidities such as hypertension, myocardial infarction, and atrial fibrillation were much less common in the young. Younger patients received more disease-modifying pharmacological therapy than their older counterparts. Across the younger age groups (<40, 40-49, and 50-59 years), mortality rates were low: 1 year 6.7, 6.6, and 7.5%, respectively; 2 year 11.7, 11.5, 13.0%; and 3 years 16.5, 16.2, 18.2%. Furthermore, 1-, 2-, and 3-year mortality rates increased sharply beyond 60 years and were greatest in the elderly (≥80 years): 28.2, 44.5, and 57.2%, respectively.

CONCLUSION

Younger patients with heart failure have different clinical characteristics including different aetiologies, more severe left ventricular dysfunction, and less severe symptoms. Three-year mortality rates are lower for all age groups under 60 years compared with older patients.

Known and missing left ventricular ejection fraction and survival in patients with heart failure: a MAGGIC meta-analysis report

AIMS

Treatment of patients with heart failure (HF) relies on measurement of LVEF. However, the extent to which EF is recorded varies markedly. We sought to characterize the patient group that is missing a measure of EF, and to explore the association between missing EF and outcome.

METHODS AND RESULTS

Individual data on 30 445 patients from 28 observational studies in the Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) project were used to compare the prevalence of co-morbidities and outcome across three groups of HF patients: those with missing EF (HF-mEF), reduced EF (HF-REF), and preserved EF (HF-PEF). A total of 29% had HF-mEF, 52% HF-REF, and 19% HF-PEF. Compared with patients in whom EF was known, patients with HF-mEF were older, had a greater prevalence of COPD and previous stroke, and were smokers. Patients with HF-mEF were less likely to receive evidence-based treatment than those with HF-REF. Adjusted mortality in HF-mEF was similar to that in HF-REF and greater than that in HF-PEF at 3 years [HF-REF, hazard ratio (HR) 1.03, 95% confidence interval (CI) 0.95-1.12); HF-PEF, HR 0.78, 95% CI 0.71-0.86].

CONCLUSION

Missing EF is common. The short- and long-term outcome of patients with HF-mEF is poor and they exhibit different co-morbidity profiles and treatment patterns compared with patients with known EF. HF patients with missing EF represent a high risk group.

Predicting survival in heart failure: a risk score based on 39 372 patients from 30 studies

AIMS

Using a large international database from multiple cohort studies, the aim is to create a generalizable easily used risk score for mortality in patients with heart failure (HF).

METHODS AND RESULTS

The MAGGIC meta-analysis includes individual data on 39 372 patients with HF, both reduced and preserved left-ventricular ejection fraction (EF), from 30 cohort studies, six of which were clinical trials. 40.2% of patients died during a median follow-up of 2.5 years. Using multivariable piecewise Poisson regression methods with stepwise variable selection, a final model included 13 highly significant independent predictors of mortality in the following order of predictive strength: age, lower EF, NYHA class, serum creatinine, diabetes, not prescribed beta-blocker, lower systolic BP, lower body mass, time since diagnosis, current smoker, chronic obstructive pulmonary disease, male gender, and not prescribed ACE-inhibitor or angiotensin-receptor blockers. In preserved EF, age was more predictive and systolic BP was less predictive of mortality than in reduced EF. Conversion into an easy-to-use integer risk score identified a very marked gradient in risk, with 3-year mortality rates of 10 and 70% in the bottom quintile and top decile of risk, respectively.

CONCLUSION

In patients with HF of both reduced and preserved EF, the influences of readily available predictors of mortality can be quantified in an integer score accessible by an easy-to-use website www.heartfailurerisk.org. The score has the potential for widespread implementation in a clinical setting.

Relationship of serum sodium concentration to mortality in a wide spectrum of heart failure patients with preserved and with reduced ejection fraction: an individual patient data meta-analysis(†): Meta-Analysis Global Group in Chronic heart failure (MAGGIC)

AIMS

Hyponatraemia has been associated with reduced survival in patients with heart failure and reduced ejection fraction (HF-REF). The relationship between serum sodium and outcome is unclear in heart failure with preserved (≥ 50%) ejection fraction (HF-PEF). Therefore, we used a large individual patient data meta-analysis to study the risk of death associated with hyponatraemia in HF-REF and in HF-PEF.

METHODS AND RESULTS

This analysis included 14 766 patients from 22 studies that recruited patients without ejection fraction inclusion criterion at baseline and reported death from any cause. Cox proportional analysis was undertaken for hyponatraemia (sodium <135 mmol/L), adjusted for variables of clinical relevance, and stratified by study. The endpoint was death from any cause at 3 years. Patients with hyponatraemia (n = 1618) and patients with normal serum sodium had similar characteristics as regards to age, gender, and ischaemic aetiology. However, patients with hyponatraemia had higher New York Heart Association class and lower blood pressure. At follow-up, there were 335 deaths among 1618 patients with hyponatraemia (21%) and 2128 deaths among 13 148 patients with normal serum sodium (16%). The risk of death appeared to increase linearly with serum sodium levels <140 mmol/L. Hyponatraemia was identified in 1199 HF-REF patients (11%) and 419 HF-PEF patients (11%). Hyponatraemia was independently predictive of death in both HF-REF [adjusted hazard ratio (HR) 1.69, 95% confidence interval (CI) 1.50-1.91] and HF-PEF (adjusted HR 1.40, 95% CI 1.10-1.79, P for interaction 0.20).

CONCLUSION

Hyponatraemia is a powerful determinant of mortality in patients with HF regardless of ejection fraction. Further work is needed to determine if correction of hyponatraemia translates into clinical benefit.

Renal dysfunction in patients with heart failure with preserved versus reduced ejection fraction: impact of the new Chronic Kidney Disease-Epidemiology Collaboration Group formula

BACKGROUND

Prior studies in heart failure (HF) have used the Modification of Diet in Renal Disease (MDRD) equation to calculate estimated glomerular filtration rate (eGFR). The Chronic Kidney Disease-Epidemiology Collaboration Group (CKD-EPI) equation provides a more-accurate eGFR than the MDRD when compared against the radionuclide gold standard. The prevalence and prognostic import of renal dysfunction in HF if the CKD-EPI equation is used rather than the MDRD is uncertain.

METHODS AND RESULTS

We used individual patient data from 25 prospective studies to stratify patients with HF by eGFR using the CKD-EPI and the MDRD equations and examined survival across eGFR strata. In 20 754 patients (15 962 with HF with reduced ejection fraction [HF-REF] and 4792 with HF with preserved ejection fraction [HF-PEF]; mean age, 68 years; deaths per 1000 patient-years, 151; 95% CI, 146-155), 10 589 (51%) and 11 422 (55%) had an eGFR <60 mL/min using the MDRD and CKD-EPI equations, respectively. Use of the CKD-EPI equation resulted in 3760 (18%) patients being reclassified into different eGFR risk strata; 3089 (82%) were placed in a lower eGFR category and exhibited higher all-cause mortality rates (net reclassification improvement with CKD-EPI, 3.7%; 95% CI, 1.5%-5.9%). Reduced eGFR was a stronger predictor of all-cause mortality in HF-REF than in HF-PEF.

CONCLUSIONS

Use of the CKD-EPI rather than the MDRD equation to calculate eGFR leads to higher estimates of renal dysfunction in HF and a more-accurate categorization of mortality risk. Renal function is more closely related to outcomes in HF-REF than in HF-PEF.

Screening for left ventricular hypertrophy in patients with type 2 diabetes mellitus in the community

BACKGROUND

Left ventricular hypertrophy (LVH) is a strong predictor of cardiovascular disease and is common among patients with type 2 diabetes. However, no systematic screening for LVH is currently recommended for patients with type 2 diabetes. The purpose of this study was to determine whether NT-proBNP was superior to 12-lead electrocardiography (ECG) for detection of LVH in patients with type 2 diabetes.

METHODS

Prospective cross-sectional study comparing diagnostic accuracy of ECG and NT-proBNP for the detection of LVH among patients with type 2 diabetes. Inclusion criteria included having been diagnosed for > 5 years and/or on treatment for type 2 diabetes; patients with Stage 3/4 chronic kidney disease and known cardiovascular disease were excluded. ECG LVH was defined as either the Sokolow-Lyon or Cornell voltage criteria. NT-proBNP level was measured using the Roche Diagnostics Elecsys assay. Left ventricular mass was assessed from echocardiography. Receiver operating characteristic curve analysis was carried out and area under the curve (AUC) was calculated.

RESULTS

294 patients with type 2 diabetes were recruited, mean age 58 (SD 11) years, BP 134/81 ± 18/11 mmHg, HbA 1c 7.3 ± 1.5%. LVH was present in 164 patients (56%). In a logistic regression model age, gender, BMI and a history of hypertension were important determinants of LVH (p < 0.05). Only 5 patients with LVH were detected by either ECG voltage criteria. The AUC for NT-proBNP in detecting LVH was 0.68.

CONCLUSIONS

LVH was highly prevalent in asymptomatic patients with type 2 diabetes. ECG was an inadequate test to identify LVH and while NT-proBNP was superior to ECG it remained unsuitable for detecting LVH. Thus, there remains a need for a screening tool to detect LVH in primary care patients with type 2 diabetes to enhance risk stratification and management.

Role of echocardiographic left ventricular mass and carotid intima-media thickness in the cardiovascular risk assessment of asymptomatic patients with type 2 diabetes mellitus

BACKGROUND

Standard cardiovascular (CV) risk assessment may underestimate risk in people with type 2 diabetes mellitus (T2DM). Cardiac and vascular imaging to detect subclinical disease may augment risk prediction. This study investigated the association between CV risk, left ventricular hypertrophy (LVH) and carotid intima-media thickness (CIMT) in patients with T2DM free of CV symptoms.

METHODS

People with T2DM without known CV disease were recruited from general practice. The 5-year risk of CV events was calculated using an adjusted Framingham equation and the prevalence of LVH and abnormal CIMT across bands of CV risk assessed. In those at intermediate risk, the number needed to scan (NNS) to reclassify one person to high risk was calculated across the group and compared in those above and below 55 years. The association between LV mass and CIMT was also assessed.

RESULTS

Mean age 57 years (SD11), 51% female. Median 5-year CV risk 14.3% (interquartile range 10.3, 19.5), 51% had LVH (American Society of Echocardiography criteria) and 31% an abnormal CIMT (age and sex criteria). In the 52% at intermediate risk, 37% had LVH and 36% an abnormal CIMT. The NNS was 1.7 using both imaging techniques, 2.7 using cardiac imaging alone or 2.8 using vascular imaging alone. Almost twice as many people >55 years had an abnormal CIMT than those <55 years.

CONCLUSIONS

Cardiac and vascular imaging to detect subclinical disease can be used to augment prediction of CV risk in people with T2DM at intermediate risk. The value of reclassifying risk is as yet unproven and requires outcome data from intervention studies.

Independent relationship of left atrial size and mortality in patients with heart failure: an individual patient meta-analysis of longitudinal data (MeRGE Heart Failure)

AIMS

Left atrial (LA) size is considered a marker of poor prognosis in heart failure (HF) patients. Prior studies have recruited relatively few subjects limiting their power to adequately analyse the interaction between LA size, left ventricular (LV) systolic and diastolic function, and prognosis.

METHOD AND RESULTS

The MeRGE collaboration combines prospective data from 18 studies in HF patients. In this analysis of data from 1157 patients, the primary endpoint was death or hospitalization for worsening HF. In multivariate analysis (Cox proportion hazard model), LA area was associated with prognosis (HR 1.03 per cm(2), 95% CI 1.02, 1.05; P < 0.0001) independently of age, NYHA class, LV ejection fraction, and restrictive filling pattern (RFP). When LA area was used as a categorical variable, the HR associated with larger LA area (above median) was 1.4 (95% CI 1.13, 1.74) and when LA area index was used, the HR was 2.36 (95% CI 1.80, 3.08). When the patients with and without RFP were divided on the basis of either LA area or LA area index, significantly higher event rates were observed in those with larger LA area.

CONCLUSION

Left atrial area is a powerful predictor of outcome among HF patients with predominantly impaired systolic function, and is independent of, and provides additional prognostic information beyond LV systolic and diastolic function.

The prognostic significance of heart failure with preserved left ventricular ejection fraction: a literature-based meta-analysis

AIMS

Heart failure (HF) with normal or preserved left ventricular (LV) ejection fraction (HFPEF) has been reported to be associated with similar outcome as HF with reduced EF (HFREF) in registry-based and epidemiological analyses, but many of these studies excluded patients who did not have EF measurements. Conversely, prior prospective studies have reported better outcome for patients with HFPEF. We performed a meta-analysis of prospective observational studies comparing all-cause mortality in patients with HFREF and HFPEF.

METHODS AND RESULTS

We searched several online databases for studies comparing outcome in HFREF and HFPEF, published before 2007.

INCLUSION CRITERIA

prospective, clinical HF, near complete EF data, and mortality outcome. Review Manager version 4.2.3 software was used for the analysis. Overall, 24 501 patients [9299 deaths (38%)] from 17 studies are included. Average follow-up was 47 months; the HFPEF group was older (69 vs. 66 years) and more likely to be female (44% vs. 26%). Of the 7688 patients with HFPEF 2468 died (32.1%), compared with 6831 of the 16 813 patients with HFREF (40.6%): odds ratio 0.51 (95% CI: 0.48, 0.55).

CONCLUSION

This literature-based meta-analysis demonstrates that mortality among patients with HFPEF was half that observed in those with HFREF, in contrast to previous reports suggesting that mortality may be similar between both groups.

Atrial fibrillation and the risk of death in patients with heart failure: a literature-based meta-analysis

BACKGROUND

Heart failure (HF) and atrial fibrillation (AF) are common, associated with significant morbidity and mortality, and frequently coexist. It is uncertain from published data if the presence of AF in patients with HF is associated with an incremental adverse outcome. The aim of this study was to combine the results of all studies investigating prognosis for patients with HF and AF compared with those in sinus rhythm (SR) to asses the mortality risk associated with this arrhythmia.

METHODS

Electronic databases were searched (Biological Abstracts, Current Contents, EMBASE, Medline, Medline In-progress, PubMed and Scopus), to 31 December 2006, using the key words congestive heart failure, heart failure, ventricular dysfunction, atrial fibrillation, atrial flutter, sinus rhythm, prognosis, outcome, death and hospitalization. Bibliographies of retrieved publications were hand searched. Studies were eligible if they included a HF population and if outcomes were reported by cardiac rhythm (AF or SR). Studies were reviewed by predetermined protocol (including quality assessment). Data were pooled using a random effects model.

RESULTS

Twenty studies were included (from 3380 initially identified) representing 32946 patients (10819 deaths). Nine randomized controlled trials (RCT) were included. The prevalence of AF was 15%, crude mortality rates were 46% (AF) and 33% (SR). The odds ratio for death was 1.33 (95% confidence interval (CI) 1.12-1.59) for AF compared with SR. Eleven observational studies were included. The prevalence of AF was 23%, crude mortality rates were 38% (AF) and 25% (SR). The odds ratio for death was 1.57 (95% CI 1.20-2.05) for AF compared with SR.

CONCLUSION

This meta-analysis demonstrates that AF is associated with worse outcomes for patients with HF compared with those with SR. Further research is required to determine whether the adverse outcome associated with AF is related to the arrhythmia itself, or to variables, such as HF severity, patient age and comorbidity.

Structural and functional cardiac abnormalities in adolescent girls with poorly controlled type 2 diabetes

OBJECTIVE

Type 2 diabetes is associated with left ventricular hypertrophy (LVH) and diastolic dysfunction, which may eventually lead to clinical heart failure. We sought to determine the cardiovascular effects of adolescent-onset type 2 diabetes.

RESEARCH DESIGN AND METHODS

We recruited diabetic girls (8 with type 2 and 11 with type 1 diabetes) from a hospital diabetes service and nondiabetic control subjects (9 lean and 11 overweight) from the schools of the diabetic subjects. Echocardiography and measurements were performed by a single observer, blinded to subject group allocation, and included M-mode left ventricular dimensions, two-dimensional left ventricular mass, Doppler diastolic flows, estimation of left ventricular filling pressure, and systolic longitudinal motion. Left ventricular mass was indexed to height and fat-free body mass. ANOVA was used to compare the groups.

RESULTS

The groups were similar in age and height, but significant differences in body composition were observed. Subjects with type 2 diabetes had larger left ventricular dimensions and left ventricular mass, which persisted when indexed to height. Diastolic filling was impaired in both diabetic groups, and systolic longitudinal function was lower in the type 2 diabetic group. Half of the group with type 2 diabetes met the published criteria for LVH and left ventricular dilatation; 25% had evidence of elevated left ventricular filling pressure in association with structural abnormalities.

CONCLUSIONS

This study has demonstrated preclinical abnormalities of cardiac structure and function in adolescent girls with type 2 diabetes, despite the short duration of diabetes and highlights the potential high cardiovascular risk occurring in adolescent type 2 diabetes.