Improve the prevention of sudden cardiac arrest in emerging countries: the Improve SCA clinical study design

Regional disparities and risk factors of mortality among patients at high risk of sudden cardiac death in emerging countries: a nonrandomized controlled trial

BACKGROUND

Comprehensive data on patients at high risk of sudden cardiac death (SCD) in emerging countries are lacking. The aim was to deepen our understanding of the SCD phenotype and identify risk factors for death among patients at high risk of SCD in emerging countries.

METHODS

Patients who met the class I indication for implantable cardioverter-defibrillator (ICD) implantation according to guideline recommendations in 17 countries and regions underrepresented in previous trials were enrolled. Countries were stratified by the WHO regional classification. Patients were or were not implanted with an ICD at their discretion. The outcomes were all-cause mortality and SCD.

RESULTS

We enrolled 4222 patients, and 3889 patients were included in the analysis. The mean follow-up period was 21.6 ± 10.2 months. There were 433 (11.1%) instances of all-cause mortality and 117 (3.0%) cases of SCD. All-cause mortality was highest in primary prevention (PP) patients from Southeast Asia and secondary prevention (SP) patients from the Middle East and Africa. The SCD rates among PP and SP patients were both highest in South Asia. Multivariate Cox regression modelling demonstrated that in addition to the independent predictors identified in previous studies, both geographic region and ICD use were associated with all-cause mortality in patients with high SCD risk. Primary prophylactic ICD implantation was associated with a 36% (HR = 0.64, 95% CI 0.531-0.802, p < 0.0001) lower all-cause mortality risk and an 80% (HR = 0.20, 95% CI = 0.116-0.343, p < 0.0001) lower SCD risk.

CONCLUSIONS

There was significant heterogeneity among patients with high SCD risk in emerging countries. The influences of geographic regions on patient characteristics and outcomes were significant. Improvement in increasing ICD utilization and uptake of guideline-directed medical therapy in emerging countries is urgent.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02099721.

Cost effectiveness of implantable cardioverter defibrillators for 1.5 primary prevention of sudden cardiac arrest in China: an analysis from the Improve SCA study

OBJECTIVES

Implantable cardioverter defibrillator (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) is underutilized in developing countries. The Improve SCA study has identified a subset of 1.5 primary prevention (1.5PP) patients with a higher risk of SCA and a significant mortality benefit from ICD therapy. From the perspective of China's healthcare system, we evaluated the cost-effectiveness of ICD therapy vs. no ICD therapy among 1.5PP patients with a view to informing clinical and policy decisions.

METHODS

A published Markov model was adjusted and verified to simulate the course of the disease and describe different health states of 1.5PP patients. The patient characteristics, mortality, utility and complication estimates were obtained from the Improve SCA study and other literature. Cost inputs were sourced from government tender prices, medical service prices and clinical experts' surveys in 9 Chinese public hospitals. For both ICD and no ICD therapy, the total medical costs and quality-adjusted life-years (QALYs) were modelled over a lifetime horizon and the incremental cost-effectiveness ratio (ICER) was calculated. Deterministic and probabilistic sensitivity analyses were performed to assess the uncertainty of the model parameters. We used the willingness-to-pay (WTP) threshold recommended by China Guidelines for Pharmacoeconomic Evaluations, one to three times China's GDP per capita (CNY85,698-CNY257,094) in 2022 Chinese Yuan.

RESULTS

The incremental cost effectiveness ratio (ICER) of ICD therapy compared to no ICD therapy is 139,652 CNY/QALY, which is about 1-2 times China's GDP per capita. The probability that ICD therapy is cost effective was 92.1%. Results from sensitivity analysis supported the findings of the base case.

CONCLUSIONS

ICD therapy compared to no ICD therapy is cost-effective for the 1.5PP patients in China.

Atrial fibrillation and the risk of sudden cardiac arrest in patients with hypertrophic cardiomyopathy - A nationwide cohort study

BACKGROUND

Hypertrophic cardiomyopathy (HCM), affecting 0.2% of the population, is the leading cause of sudden cardiac arrest (SCA). Incident atrial fibrillation (AF) is associated with an increased risk of SCA in general population. To determine whether AF is associated with an increased risk of SCA in patients with HCM.

METHODS

This nationwide cohort study analyzed data from Registry for Catastrophic Illness, which encompassed almost 100% of the patients with HCM in Taiwan from 1996 to 2013. Follow-up and data analysis ended December 31, 2013. The main outcome was physician-adjudicated SCA, defined as death from a sudden, pulseless condition presumed due to a ventricular tachyarrhythmia. The secondary outcome was non-sudden cardiac death (NSCD), which was heart failure death, stroke death and non-HCM related death. We used Cox proportional hazards models to assess the association between AF and SCA/NSCD, adjusting for baseline demographic and cardiovascular risk factors.

FINDINGS

A total 10,910 subjects participated in this study with mean age of 62 years. Among enrolled subjects, 1,169 (10.7%) developed AF, which was independently associated with elder age, female sex, and history of heart failure (HF) hospitalization. During follow-up (median, 8.5 years and 2th to 7th interquartile range, 3.6 to 16.5 years), 371 SCA (166 in AF and 205 in non-AF group) and 797 NSCD (417 in AF and 380 in non-AF group) events occurred. The crude incidence rates of SCA were 12.45/1000 person-years (with AF) and 3.57/1000 person-years (without AF). The crude incidence rates for NSCD were 31.29/1000 person-years (with AF) and 6.63/1000 person-years (without AF). The multivariable hazard ratios (HRs) (95% CI) of AF for SCA and NSCD were 3.633 (2.756-4.791) and 2.086 (1.799-2.418), respectively. Furthermore, among the etiologies of NSCD, subjects with AF was at most risk of stroke-related death (HR, 6.609; 95% CI, 3.794-9.725).

INTERPRETATION

Incident AF is associated with an increased risk of SCA and NSCD in the HCM population. Early detection of AF may provide more comprehensive risk stratification of SCD in HCM population. Because of underuse of oral anticoagulants and the absence of primary prevention ICD therapy in our cohort, the application of our findings was limited for the general HCM population in the current clinical practice.

FUNDING

None.

Implantable cardioverter defibrillator therapy is cost effective for primary prevention patients in Taiwan: An analysis from the Improve SCA trial

Objective

Implantable cardiac defibrillators (ICDs) for primary prevention (PP) of sudden cardiac arrest (SCA) are well-established but underutilized globally. The Improve SCA study has identified a cohort of patients called 1.5 primary prevention (1.5PP) based on PP patients with the presence of certain risk factors. We evaluated the cost-effectiveness of ICD therapy compared to no ICD among the PP population and the subset of 1.5PP patients in Taiwan.

Methods

A Markov model was run over a lifetime time horizon from the Taiwan payer perspective. Mortality and utility estimates were obtained from the literature (PP) and the IMPROVE SCA trial (1.5PP). Cost inputs were obtained from the Taiwan National Health Insurance Administration (NHIA), Ministry of Health and Welfare. We used a willingness-to-pay (WTP) threshold of NT$2,100,000, as established through standard WTP research methods and in alignment with World Health Organization recommendations.

Results

The total discounted costs for ICD therapy and no ICD therapy were NT$1,664,259 and NT$646,396 respectively for PP, while they were NT$2,410,603 and NT$905,881 respectively for 1.5PP. Total discounted QALYs for ICD therapy and no ICD therapy were 6.48 and 4.98 respectively for PP, while they were 10.78 and 7.71 respectively for 1.5PP. The incremental cost effectiveness ratio was NT$708,711 for PP and NT$441,153 for 1.5PP, therefore ICD therapy should be considered cost effective for PP and highly cost effective for 1.5PP.

Conclusions

ICD therapy compared to no ICD therapy is cost-effective in the whole PP population and highly cost-effective in the subset 1.5PP population in Taiwan.

A prognostic nomogram for event-free survival in patients with atrial fibrillation before cardiac resynchronization therapy

Background

Atrial fibrillation (AF), one of the most common comorbidities of heart failure (HF), is associated with worse long-term prognosis in HF patients receiving cardiac resynchronization therapy (CRT). However, there is still no convenient tool to identify CRT candidates with AF who are at high risk of mortality and hospitalization due to HF.

Methods

We included 152 consecutive patients with AF for CRT in our hospital from January 2009 to July 2019. Multiple imputation was used for missing values. With imputed datasets, a multivariate Cox regression model was performed for variable selection using the backward stepwise method to predict all-cause mortality and HF readmissions. A nomogram and nomogram-based scoring system were constructed from the selected predictors. Then, internal validation and calibration were achieved by the bootstrap method, deriving the corrected concordance index and calibration curves. Sensitivity analysis was also performed to validate our selected predictors.

Results

Five predictors were incorporated in the nomogram, including N-terminal pro brain natriuretic protein (NT-proBNP) > 1745 pg/mL, history of syncope, previous pulmonary hypertension, moderate or severe tricuspid regurgitation, thyroid-stimulating hormone (TSH) > 4 mIU/L. The concordance index (0.70, 95% CI 0.62–0.77), corrected concordance index (0.67, 95% CI 0.59–0.74) and calibration curve showed optimal discrimination and calibration of the established nomogram. A significant difference in overall event-free survival was recognized by the nomogram-derived scores for patients with high risk (> 50 points), intermediate risk (21–50 points) and low risk (0–20 points) before CRT.

Conclusion

Our internally validated nomogram may be an applicable tool for the early risk stratification of CRT candidates with AF.

A 5-year change of knowledge and willingness by sampled respondents to perform bystander cardiopulmonary resuscitation in a metropolitan city

Background

Nationwide and regional interventions can help improve bystander cardiopulmonary resuscitation (CPR) awareness, knowledge, and the willingness. Periodic community investigation will help monitor the effect. This study aimed to compare the experience of CPR education, CPR knowledge, and CPR willingness, during a 5-year interval.

Methods

This is a pre and post study. Two surveys were done in February 2012 and December 2016. National and regional intervention including legislation promoting public involvement, standardizing CPR education programs, training CPR instructors, and installing supporting organizations were done at the period. In both surveys, respondents were selected via quota sampling in Daegu Metropolitan City and answered the survey through face-to-face interview. Respondents’ general demographic characteristics, CPR educational experience, CPR knowledge and CPR willingness were questioned.

Results

Total of 2141 respondents (1000 in 2012, 1141 in 2016) were selected. The percentage of respondents who received CPR education itself and recent education were higher after intervention compared to before intervention (36.2% vs. 55.1%, 16.9% vs. 30.1%, respectively). Correct knowledge of performing CPR seems to be improved overall (1.6% vs. 11.7%, odd ratio 14.28, 95% confidence interval 5.68–35.94). However, less respondents were willing to perform CPR on strangers (54.5% vs 35.0%).

Conclusion

Nationwide and regional interventions to promote bystander CPR and CPR education were associated with increased CPR education experience and improved correct CPR knowledge in performing bystander CPR. Willingness to perform bystander CPR on family did not increase significantly and CPR willingness to strangers was decreased. Additional legal and technological measures should be implemented to promote bystander CPR.

Sudden cardiac death in China: current status and future perspectives

Sudden cardiac death (SCD) is a major cause of mortality worldwide. Similar to the number of SCDs in western countries including the USA, the number of SCDs in China is ∼544,000 annually. However, there are significant differences in patient characteristics between Chinese primary prevention population and U.S. primary prevention population. In contrast to western countries where implantable cardioverter-defibrillator (ICD) devices have been well adopted as a major effective method for both primary and secondary prevention of SCD, China has a low prevalence of ICD utilization (∼1.5 device per 1 million people). Socioeconomic and political factors, awareness and knowledge of SCD, and the difference in disease patterns have led to the underutilization of ICD in China. China, as the most populated and the second largest economic country in the world, has now taken variable approaches to address this pressing health problem and enhances the delivery of lifesaving therapies, including arrhythmia ablation and medical treatment besides ICD, to patients who are at risk of SCD.