Differences in late cardiovascular mortality following acute myocardial infarction in three major Asian ethnic groups

Gender differences in fasting and postprandial metabolic traits predictive of subclinical atherosclerosis in an asymptomatic Chinese population

The prediction utility of Framingham Risk Score in populations with low conventional cardiovascular risk burden is limited, particularly among women. Gender-specific markers to predict cardiovascular risk in overtly healthy people are lacking. In this study we hypothesize that postprandial responses triggered by a high-calorie meal test differ by gender in their ability to triage asymptomatic subjects into those with and without subclinical atherosclerosis. A total of 101 healthy Chinese subjects (46 females, 55 males) at low risk of coronary heart disease completed the study. Subjects underwent cardiovascular imaging and postprandial blood phenotyping after consuming a standardized macronutrient meal. Prediction models were developed using logistic regression and subsequently subjected to cross-validation to obtain a de-optimized receiver operating characteristic (ROC) curve. Distinctive gender differences in postprandial trajectories of glucose, lipids and inflammatory markers were observed. We used gender-specific association with different combinations of postprandial predictors to develop 2 models for predicting risk of subclinical atherosclerosis in males (ROC AUC = 0.7867, 95% CI 0.6567, 0.9166) and females (ROC AUC = 0.9161, 95% CI 0.8340, 0.9982) respectively. We report novel postprandial models for predicting subclinical atherosclerosis in apparently healthy Asian subjects using a gender-specific approach, complementing the conventional Framingham Risk Score.Clinical Trial Registration: The trial was registered at clinicaltrials.gov as NCT03531879.

Outcomes of a multi-ethnic Asian population on combined treatment with clopidogrel and omeprazole in 12,440 patients

Omeprazole is commonly co-prescribed with clopidogrel. Clopidogrel requires bio-activation by cytochrome P450 CYP2C19. Omeprazole may reduce clopidogrel's antithrombotic efficacy by inhibiting CYP2C19. Studies in Caucasians receiving omeprazole with clopidogrel showed no significant increase in death and myocardial infarction with this drug-drug interaction. There are limited large-scale studies in Asians, who may have a greater prevalence of CYP2C19 loss-of-function polymorphisms. A single centre retrospective cohort study was undertaken based on a review of medication records and prescription data. Patients prescribed clopidogrel from 2009 to 2012 were followed-up with until December 2012 (median:29 months). The primary outcome was all-cause mortality and secondary outcomes were myocardial infarction (MI), cerebrovascular accidents, and subsequent coronary interventions. Of 12,440 patients prescribed clopidogrel, 62%(n = 7714) were on omeprazole (63.8% Chinese, 13.9% Malay, 12.4% Indian, 10.0% others), and 38%(n = 4726) were not on omeprazole or other proton pump inhibitors (62.6% Chinese, 13.5% Malay, 10.7% Indian, 13.2% others). Mortality after co-prescription occurred in 14.3%(n = 1101) of patients, compared to 6.3%(n = 300) of patients prescribed clopidogrel only. Multivariate analysis using propensity score adjusted analysis showed no significant increase in all-cause mortality with co-prescription (adjusted hazards ratio [AHR] 1.13, [95%CI 0.95-1.35]). Patients on co-prescription had a higher risk of subsequent MI (16% vs 3.8%; AHR 2.03 [95%CI 1.70-2.44]), but not of cerebrovascular accidents (5.0% vs 2.0%; AHR 0.98 [95%CI 0.76-1.27]) or coronary interventions (1.7% vs 0.7%; AHR 1.28 [95%CI 0.83-1.96]). The risk of a subsequent MI was higher in the Malay (AHR 2.43 [95%CI 1.68-3.52]) and Chinese (AHR 2.06 [95%CI 1.63-2.60]) population as compared to the Indian (AHR 1.56 [95%CI 1.06-2.31]) population. In conclusion, the use of clopidogrel with omeprazole is associated with an increased risk of MI, but not mortality or stroke, in this multi-ethnic Asian population. These risks appear to vary among different ethnic groups.

Comparative overview of ST-elevation myocardial infarction epidemiology, demographics, management, and outcomes in five Asia-Pacific countries: a meta-analysis

The aim of this study is to gain insight into the differences in demographics of ST-elevation myocardial infarction (STEMI) patients in Asia-Pacific, as well as inter-country variation in treatment and mortality outcomes. Systematic review of published studies and reports from known registries in Australia, Japan, Korea, Singapore, and Malaysia that began data collection after the year 2000. Supplementary self-report survey questionnaire on public health data answered by representative cardiologists working in these countries. Twenty studies comprising of 158 420 patients were included in the meta-analysis. The mean age was 61.6 years. Chronic kidney disease prevalence was higher in Japan, while dyslipidaemia was low in Korea. Use of aspirin, P2Y12 inhibitors, and statins were high throughout, but ACEi/ARB and β-blocker prescriptions were lower in Japan and Malaysia. Reperfusion strategies varied greatly, with high rates of primary percutaneous coronary intervention (pPCI) in Korea (91.6%), whilst Malaysia relies far more on fibrinolysis (72.6%) than pPCI (9.6%). Similarly, mortality differed, with 1-year mortality from STEMI was considerably greater in Malaysia (17.9%) and Singapore (11.2%) than in Korea (8.1%), Australia (7.8%), and Japan (6.2%). The countries were broadly similar in development and public health indices. Singapore has the highest gross national income and total healthcare expenditure per capita, whilst Malaysia has the lowest. Primary PCI is available in all countries 24/7/365. Despite broadly comparable public health systems, differences exist in patient profile, in-hospital treatment, and mortality outcomes in these five countries. Our study reveals areas for improvements. The authors advocate further registry-based multi-country comparative studies focused on the Asia-Pacific region.

Toll-like receptor 7 deficiency promotes survival and reduces adverse left ventricular remodelling after myocardial infarction

AIMS

The Toll-like receptor 7 (TLR7) is an intracellular innate immune receptor activated by nucleic acids shed from dying cells leading to activation of the innate immune system. Since innate immune system activation is involved in the response to myocardial infarction (MI), this study aims to identify if TLR7 is involved in post-MI ischaemic injury and adverse remodelling after MI.

METHODS AND RESULTS

TLR7 involvement in MI was investigated in human tissue from patients with ischaemic heart failure, as well as in a mouse model of permanent left anterior descending artery occlusion in C57BL/6J wild type and TLR7 deficient (TLR7-/-) mice. TLR7 expression was up-regulated in human and mouse ischaemic myocardium after MI. Compared to wild type mice, TLR7-/- mice had less acute cardiac rupture associated with blunted activation of matrix metalloproteinase 2, increased expression of tissue inhibitor of metalloproteinase 1, recruitment of more myofibroblasts, and the formation of a myocardial scar with higher collagen fibre density. Furthermore, inflammatory cell influx and inflammatory cytokine expression post-MI were reduced in the TLR7-/- heart. During a 28-day follow-up after MI, TLR7 deficiency resulted in less chronic adverse left ventricular remodelling and better cardiac function. Bone marrow (BM) transplantation experiments showed that TLR7 deficiency in BM-derived cells preserved cardiac function after MI.

CONCLUSIONS

In acute MI, TLR7 mediates the response to acute cardiac injury and chronic remodelling probably via modulation of post-MI scar formation and BM-derived inflammatory infiltration of the myocardium.

Independent Predictors of Cardiac Mortality and Hospitalization for Heart Failure in a Multi-Ethnic Asian ST-segment Elevation Myocardial Infarction Population Treated by Primary Percutaneous Coronary Intervention

We aimed to identify independent predictors of cardiac mortality and hospitalization for heart failure (HHF) from a real-world, multi-ethnic Asian registry [the Singapore Myocardial Infarction Registry] of ST-segment elevation myocardial infarction (STEMI) patients treated by primary percutaneous coronary intervention. 11,546 eligible STEMI patients between 2008 and 2015 were identified. In-hospital, 30-day and 1-year cardiac mortality and 1-year HHF rates were 6.4%, 6.8%, 8.3% and 5.2%, respectively. From the derivation cohort (70% of patients), age, Killip class and cardiac arrest, creatinine, hemoglobin and troponin on admission and left ventricular ejection fraction (LVEF) during hospitalization were predictors of in-hospital, 30-day and 1-year cardiac mortality. Previous ischemic heart disease (IHD) was a predictor of in-hospital and 30-day cardiac mortality only, whereas diabetes was a predictor of 1-year cardiac mortality only. Age, previous IHD and diabetes, Killip class, creatinine, hemoglobin and troponin on admission, symptom-to-balloon-time and LVEF were predictors of 1-year HHF. The c-statistics were 0.921, 0.901, 0.881, 0.869, respectively. Applying these models to the validation cohort (30% of patients) showed good fit and discrimination (c-statistic 0.922, 0.913, 0.903 and 0.855 respectively; misclassification rate 14.0%, 14.7%, 16.2% and 24.0% respectively). These predictors could be incorporated into specific risk scores to stratify reperfused STEMI patients by their risk level for targeted intervention.

Racial/ethnic disparities among Asian Americans in inpatient acute myocardial infarction mortality in the United States

Background

Acute myocardial infarction (AMI) is a common high-risk disease with inpatient mortality of 5% nationally. But little is known about this outcome among Asian Americans (Asians), a fast growing racial/ethnic minority in the country. The objectives of the study are to obtain near-national estimates of differences in AMI inpatient mortality between minorities (including Asians) and non-Hispanic Whites and identify comorbidities and sociodemographic characteristics associated with these differences.

Method

This is a retrospective analysis of 2010–2011 state inpatient discharge data from 10 states with the largest share of Asian population. We identified hospitalization with a primary diagnosis of AMI using the ICD-9 code and used self-reported race/ethnicity to identify White, Black, Hispanic, and Asian. We performed descriptive analysis of sociodemographic characteristics, medical comorbidities, type of AMI, and receipt of cardiac procedures. Next, we examined overall inpatient AMI mortality rate based on patients’ race/ethnicity. We also examined the types of AMI and a receipt of invasive cardiac procedures by race/ethnicity. Lastly, we used sequential multivariate logistic regression models to study inpatient mortality for each minority group compared to Whites, adjusting for covariates.

Results

Over 70% of the national Asian population resides in the 10 states. There were 496,472 hospitalizations with a primary diagnosis of AMI; 75% of all cases were Whites, 10% were Blacks, 12% were Hispanics, and 3% were Asians. Asians had a higher prevalence of cardiac comorbidities, including hypertension, diabetes, and kidney failure compared to Whites (p-value< 0.01). There were 158,623 STEMI (ST-elevation AMI), and the proportion of hospitalizations for STEMI was the highest for Asians (35.2% for Asians, 32.7% for Whites, 25.3% for Blacks, and 32.1% for Hispanics). Asians had the highest rates of inpatient AMI mortality: 7.2% for Asians, 6.3% for Whites, 5.4% for Blacks, and 5.9% for Hispanics (ANOVA p-value < 0.01). In adjusted analyses, Asians (OR = 1.11 [95% CI: 1.04–1.19]) and Hispanics (OR = 1.14 [1.09–1.19]) had a higher likelihood of inpatient mortality compared to Whites.

Conclusions

Asians had a higher risk-adjusted likelihood of inpatient AMI mortality compared to Whites. Further research is needed to identify the underlying reasons for this finding to improve AMI disparities for Asians.

Educational attainment and differences in relative survival after acute myocardial infarction in Norway: a registry-based population study

BACKGROUND

Although there is a broad societal interest in socioeconomic differences in survival after an acute myocardial infarction, only a few studies have investigated how such differences relate to the survival in general population groups. We aimed to investigate education-specific survival after acute myocardial infarction and to compare this with the survival of corresponding groups in the general population.

METHODS

Our study included the entire population of Norwegian patients admitted to hospitals for acute myocardial infarction during 2008-2010, with a 6- year follow-up period. Patient survival was measured relative to the expected survival in the general population for three educational groups: primary, secondary and tertiary. Education, sex, age and calendar year-specific expected survival were obtained from population life tables and adjusted for the presence of infarction-related mortality.

RESULTS

Six-year patient survivals were 56.3% (55.3-57.2) and 65.5% (65.6-69.3) for the primary and tertiary educational groups (95% CIs), respectively. Also 6-year relative survival was markedly lower for the primary educational group: 70.2% (68.6-71.8) versus 81.2% (77.4-84.4). Throughout the follow-up period, patient survival tended to remain lower than the survival in the general population with the same educational background.

CONCLUSION

Both patient survival and relative survival after acute myocardial infarction are positively associated with educational level. Our findings may suggest that secondary prevention has been more effective for the highly educated.

Risk of death from cardiovascular disease following breast cancer in Southeast Asia: a prospective cohort study

Breast cancer incidence and survival is high in Southeast Asia. As such, many women diagnosed with breast cancer are at risk of dying of other causes. Given the increased risk of cardiotoxicity induced by breast cancer treatments, it is important to identify patients at high risk of cardiovascular disease (CVD) mortality. The aim of this study was to investigate if this risk varies by age and ethnicity. Patient details were obtained from 5,868 Chinese, Malay, and Indian women diagnosed with in situ or non-metastasized invasive breast cancer at the National University Hospital of Singapore and KK Women's and Children's Hospital in Singapore. Death causes were obtained from the National Registry of Births and Deaths. Flexible parametric survival models estimated CVD mortality rates and hazard ratios. During a median follow-up of six years, 1,010 deaths occurred of which 6.8% were due to CVD. CVD mortality rates of older women peaked within the first year following diagnosis and increased over time since diagnosis. Indian had more than double the risk of CVD mortality than Chinese, independent of age at diagnosis and stage. Taking ethnicity and age into account may promote CVD risk stratification and management in (Southeast Asian) women with breast cancer.

Effects of Ethnicity on the Prevalence of Obstructive Sleep Apnoea in Patients with Acute Coronary Syndrome: A Pooled Analysis of the ISAACC Trial and Sleep and Stent Study

BACKGROUND

Obstructive sleep apnoea (OSA) is an emerging risk factor for acute coronary syndrome (ACS). We sought to determine the effects of ethnicity on the prevalence of OSA in patients presenting with ACS who participated in an overnight sleep study.

METHODS

A pooled analysis using patient-level data from the ISAACC Trial and Sleep and Stent Study was performed. Using the same portable diagnostic device, OSA was defined as an apnoea-hypopnoea index of ≥15 events per hour.

RESULTS

A total of 1961 patients were analysed, including Spanish (53.6%, n=1050), Chinese (25.5%, n=500), Indian (12.0%, n=235), Malay (6.1%, n=119), Brazilian (1.7%, n=34) and Burmese (1.2%, n=23) populations. Significant differences in body mass index (BMI) were found among the various ethnic groups, averaging from 25.3kg/m² for Indians and 25.4kg/m² for Chinese to 28.6kg/m² for Spaniards. The prevalence of OSA was highest in the Spanish (63.1%), followed by the Chinese (50.2%), Malay (47.9%), Burmese (43.5%), Brazilian (41.2%), and Indian (36.1%) patients. The estimated odds ratio of BMI on OSA was highest in the Chinese population (1.17; 95% confidence interval: 1.10-1.24), but was not significant in the Spanish, Burmese or Brazilian populations. The area under the curve (AUC) for the Asian patients (ranging from 0.6365 to 0.6692) was higher than that for the Spanish patients (0.5161).

CONCLUSION

There was significant ethnic variation in the prevalence of OSA in patients with ACS. The magnitude of the effect of BMI on OSA was greater in the Chinese population than in the Spanish patients.

Symptom-to-door delay among patients with ST-segment elevation myocardial infarction in Singapore

OBJECTIVES

Symptom-to-door time (S2D) is one of the important components of ischaemic time, which might affect the infarct size and outcomes of acute myocardial infarction. The aim of the present study was to identify patients' characteristics associated with delayed symptom-onset-to-arrival at EDs in ST-segment elevation myocardial infarction (STEMI) patients in Singapore.

METHODS

Retrospective data of STEMI patients presenting to the ED of all public hospitals with onsite primary percutaneous coronary intervention facilities between 2010 and 2012 were obtained from the Singapore Myocardial Infarction Registry. Based on the S2D of 120 min, characteristics of patients were compared between short S2D (≤120 min) and long S2D (>120 min). Multivariate logistic and linear regression analyses were performed.

RESULTS

Out of 3848 patients, 1682 patients had an S2D of ≤120 min, and 2166 had an S2D >120 min. In the multivariate analyses, older age, Malay ethnicity, diabetes mellitus, presenting symptoms of back and epigastric pain were independently associated with long S2D. Patients who utilised the emergency medical services, presented after office hours and with symptoms of chest pain, breathlessness, diaphoresis and past history of percutaneous transluminal coronary angioplasty/primary percutaneous coronary intervention, were independently associated with short S2D. Patients with long S2D had lower probability of receiving reperfusion treatment with delayed symptom-to-balloon and door-to-balloon time and higher probabilities of complications and mortality.

CONCLUSION

The present study shows that longer S2D was associated with older age, ethnicity, diabetes mellitus, delay in receiving early reperfusion treatment and poorer prognosis.

Influence of Ethnicity, Age, and Time on Sex Disparities in Long-Term Cause-Specific Mortality After Acute Myocardial Infarction

Background

We examined the influence of sex, ethnicity, and time on competing cardiovascular and noncardiovascular causes of death following acute myocardial infarction in a multiethnic Asian cohort.

Methods and Results

For 12 years, we followed a prospective nationwide cohort of 15 151 patients (aged 22–101 years, median age 63 years; 72.3% male; 66.7% Chinese, 19.8% Malay, 13.5% Indian) who were hospitalized for acute myocardial infarction between 2000 and 2005. There were 6463 deaths (4534 cardiovascular, 1929 noncardiovascular). Compared with men, women had a higher risk of cardiovascular death (age‐adjusted hazard ratio [HR] 1.3, 95% CI 1.2–1.4) but a similar risk of noncardiovascular death (HR 0.9, 95% CI 0.8–1.0). Sex differences in cardiovascular death varied by ethnicity, age, and time. Compared with Chinese women, Malay women had the greatest increased hazard of cardiovascular death (HR 1.4, 95% CI 1.2–1.6) and a marked imbalance in death due to heart failure or cardiomyopathy (HR 3.4 [95% CI 1.9–6.0] versus HR 1.5 [95% CI 0.6–3.6] for Indian women). Compared with same‐age Malay men, Malay women aged 22 to 49 years had a 2.5‐fold (95% CI 1.6–3.8) increased hazard of cardiovascular death. Sex disparities in cardiovascular death tapered over time, least among Chinese patients and most among Indian patients; the HR comparing cardiovascular death of Indian women and men decreased from 1.9 (95% CI 1.5–2.4) at 30 days to 0.9 (95% CI 0.5–1.6) at 10 years.

Conclusion

Age, ethnicity, and time strongly influence the association between sex and specific cardiovascular causes of mortality, suggesting that health care policy to reduce sex disparities in acute myocardial infarction outcomes must consider the complex interplay of these 3 major modifying factors.

Comparison of Long-Term Mortality of Patients Aged ≤40 Versus >40 Years With Acute Myocardial Infarction

Young patients with acute myocardial infarction (MI) have a more favorable prognosis than older patients with MI. However, there are limited data comparing the prognosis of young patients with MI with young population controls. Comparison with an age-matched background population could unmask residual mortality risk in young patients with MI that would otherwise not be apparent when merely comparing the mortality risk of young and older patients with MI. We studied 15,151 patients with AMI from 2000 to 2005, of which 601 patients were ≤40 years (young MI). The relative survival ratio (RSR) was calculated as the ratio of the observed survival of patients with MI divided by the expected survival, estimated from the background population (n = 3,771,700) matched for age, gender, and follow-up year. An RSR of <1.0 or >1.0 indicates poorer or better survival, respectively, than the background population. The 12-year all-cause and cardiovascular mortality of young versus older patients was 12.8% versus 50.7% (p <0.001) and 9.2% versus 34.5% (p <0.001), respectively. The adjusted hazard ratio (95% confidence interval) for all-cause and cardiovascular mortality comparing young with older patients was 0.20 (0.16 to 0.27) and 0.27 (0.20 to 0.36), respectively. The RSR (95% confidence interval) of young and older patients was, respectively, 0.969 (0.950 to 0.980) and 0.804 (0.797 to 0.811) at 1 year, 0.942 (0.918 to 0.960) and 0.716 (0.707 to 0.726) at 5 years, and 0.908 (0.878 to 0.938) and 0.638 (0.620 to 0.654) at 9 years. In conclusion, despite a fivefold lower long-term mortality than older patients with MI, young patients with MI remain at significantly greater risk of long-term mortality than an age-matched background population.

Rehabilitation Outcomes After Inpatient Rehabilitation for Lower Extremity Amputations in Patients With Diabetes

OBJECTIVE

To identify factors associated with functional gain, discharge destination, and long-term survival after inpatient rehabilitation in patients with lower extremity amputation and diabetes.

DESIGN

Retrospective medical records review.

SETTING

All community hospitals.

PARTICIPANTS

Patients with diabetes (N=256) admitted for inpatient rehabilitation after lower extremity amputation.

INTERVENTIONS

Not applicable.

MAIN OUTCOMES MEASURES

Absolute functional gain (AFG) using the Shah-modified Barthel Index, discharge destination, and long-term survival for each patient.

RESULTS

Length of stay (B=.15; 95% confidence interval [CI], .08-.21; P<.001) and admission functional status (B=-.09; 95% CI, -.18 to -.01; P=.032) were significantly associated with AFG. Availability of caregiver (foreign domestic worker: odds ratio [OR], 16.39; 95% CI, 4.65-57.78; P<.001; child: OR, 3.82; 95% CI, 1.31-11.12; P=.014; spouse: OR, 2.82; 95% CI, 1.07-7.46; P=.037 vs none), Charlson Comorbidity Index of 1 (OR, 4.32; 95% CI, 1.34-13.93; P=.014 vs ≥4), and younger age (OR, .96; 95% CI, .93-.99; P=.02) were significantly associated with being discharged home. Admission functional status (hazard ratio [HR], .98; 95% CI, .97-.99; P<.001), AFG (HR, .99; 95% CI, 0.97-1.00; P=.058), Charlson Comorbidity Index (1 vs ≥4: HR, .42; 95% CI, .24-.77; P=.004), ischemic heart disease (HR, 2.25; 95% CI, 1.27-4.00; P=.006), discharge destination (other vs home: HR, 1.82; 95% CI, 1.02-3.23; P=.041), age (HR, 1.02; 95% CI, 1.00-1.03; P=.082), and ethnicity (Malay vs Chinese: HR, .37; 95% CI, .16-.87; P=.022) predicted survival postamputation.

CONCLUSIONS

Admission functional status predicted both functional gain during rehabilitation and survival in these patients. We also found ethnic differences in outcomes, with Malays having better survival after amputation. Lastly, there appears to be greater reliance on foreign domestic workers as caregivers, with patients with foreign domestic workers as their primary caregiver having the highest odds of being discharged home.

A Chinese Immigrant Paradox? Low Coronary Heart Disease Incidence but Higher Short-Term Mortality in Western-Dwelling Chinese Immigrants: A Systematic Review and Meta-Analysis

BACKGROUND

Chinese form a large proportion of the immigrant population in Western countries. There is evidence that Chinese immigrants experience an increased risk of coronary heart disease (CHD) after immigration in part due to cultural habits and acculturation. This is the first systematic review and meta-analysis that aims to examine the risk of CHD in people of Chinese ethnicity living in Western countries, in comparison with whites and another major immigrant group, South Asians.

METHODS AND RESULTS

Literature on the incidence, mortality, and prognosis of CHD among Chinese living in Western countries was searched systematically in any language using 6 electronic databases up to December 2014. Based on the meta-analysis, Chinese had lower incidence of CHD compared with whites (odds ratio 0.29; 95% CI: 0.24-0.34) and South Asians (odds ratio 0.37; 95% CI: 0.24-0.57) but higher short-term mortality after first hospitalization for acute myocardial infarction compared with whites (odds ratio 1.34; 95% CI, 1.04-1.73) and South Asians (odds ratio 1.82; 95% 1.33-2.50). There was no significant difference between Chinese immigrants and whites in long-term outcomes (mortality and recurrent events) after acute myocardial infarction.

CONCLUSIONS

These findings provide an important focus for resource planning to enhance early secondary prevention of CHD to improve short-term survival outcomes among Western-dwelling Chinese immigrants.