Cost-effectiveness of in-home automated external defibrillators for individuals at increased risk of sudden cardiac death

A Systematic Review of Cost-Effectiveness of Treating Out of Hospital Cardiac Arrest: Implications for Resource-limited Health Systems

Background

Out-of-hospital cardiac arrest (OHCA) is a prevalent condition with high mortality and poor outcomes even in settings where extensive emergency care resources are available. Interventions to address OHCA have had limited success, with survival rates below 10% in national samples of high-income countries. In resource-limited settings, where scarcity requires careful priority setting, more data is needed to determine the optimal allocation of resources.

Objective

To establish the cost-effectiveness of OHCA care and assess the affordability of interventions across income settings.

Methods

The authors conducted a systematic review of economic evaluations on interventions to address OHCA. Included studies were (1) economic evaluations (beyond a simple costing exercise); and (2) assessed an intervention in the chain of survival for OHCA. Article quality was assessed using the CHEERs checklist and data summarised. Findings were reported by major themes identified by the reviewers. Based upon the results of the cost-effectiveness analyses we then conduct an analysis for the progressive realization of the OHCA chain of survival from the perspective of decision-makers facing resource constraints.

Results

468 unique articles were screened, and 46 articles were included for final data abstraction. Studies predominantly used a healthcare sector perspective, modeled for all patients experiencing non-traumatic cardiac OHCA, were based in the US, and presented results in US Dollars. No studies reported results or used model inputs from low-income settings. Progressive realization of the chain of survival could likely begin with investments in TOR protocols, professional prehospital defibrillator use, and CPR training followed by distribution of AEDs in high-density public locations. Finally, other interventions such as indiscriminate defibrillator placement or adrenaline use, would be the lowest priority for early investment.

Conclusion

Our review found no high-quality evidence on the cost-effectiveness of treating OHCA in low-resource settings. Existing evidence can be utilized to develop a roadmap for the development of a cost-effective approach to OHCA care, however further economic evaluations using context-specific data are crucial to accurately inform prioritization of scarce resources within emergency care in these settings.

Economic evaluation of automated external defibrillator deployment in public settings for out-of-hospital cardiac arrest: a systematic review

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a major issue in aging populations. The use of automatic external defibrillators (AEDs) in public places improves cardiac arrest survival rates. The purpose of this study is to review economic evaluation studies of the use of AED technology in public settings for cardiac arrest resuscitation.

METHODS

Our search covered 1990-2021 and included PubMed, Cochrane Library, Embase, Scopus, and Web of Science. We included studies that analyzed cost-effectiveness, cost-utility and cost-benefit of the AED technology. Also, we performed the quality assessment of the studies through the checklist of quality assessment standard of health economic studies (QHES).

RESULTS

Our inclusion criteria were met by 25 studies. AEDs are found to be cost-effective in places with a high occurrence of cardiac arrest. In addition, proper integration of drones with AEDs into existing systems has the potential to significantly improve OHCA survival rates.

CONCLUSION

The present study found that putting AEDs in high-cardiac arrest and crowded areas reduces average costs. Despite this, the costs associated with acquiring and maintaining AEDs prevent their widespread use. Further research is needed to evaluate feasibility and explore innovative strategies for AED maintenance and accessibility.

Estimation of Health and Economic Benefits of a Small Automatic External Defibrillator for Rapid Treatment of Sudden Cardiac Arrest (SMART): A Cost-Effectiveness Analysis

Background

Sudden cardiac arrest (SCA) occurs in 0.4% of the general population and up to 6% or more of at-risk groups each year. Early CPR and defibrillation improves SCA outcomes but access to automatic external defibrillators (AEDs) remains limited.

Methods

Markov models were used to evaluate the cost-effectiveness of a portable SMART (SMall AED for Rapid Treatment of SCA) approach to early SCA management over a life-time horizon in at-risk and not at-risk populations. Simulated patients (n = 600,000) who had not received an implantable cardioverter defibrillator (ICD) were randomized to a SMART device with CPR prompts or non-SMART approaches. Annual SCA risk was varied from 0.2 to 3.5%. Analysis was performed in a US economy from both societal (SP) and healthcare (HP) perspectives to evaluate the number of SCA fatalities prevented by SMART, and SMART cost-effectiveness at a threshold of $100,000/Quality Adjusted Life Year (QALY).

Results

A SMART approach was cost-effective when annual SCA risk exceeded 1.51% (SP) and 1.62% (HP). The incremental cost-effectiveness ratios (ICER) were $95,251/QALY (SP) and $100,797/QALY (HP) at a 1.60% SCA annual risk. At a 3.5% annual SCA risk, SMART was highly cost-effective from both SP and HP [ICER: $53,925/QALY (SP), $59,672/QALY (HP)]. In microsimulation, SMART prevented 1,762 fatalities across risk strata (1.59% fatality relative risk reduction across groups). From a population perspective, SMART could prevent at least 109,839 SCA deaths in persons 45 years and older in the United States.

Conclusions and Relevance

A SMART approach to SCA prophylaxis prevents fatalities and is cost-effective in patients at elevated SCA risk. The availability of a smart-phone enabled pocket-sized AED with CPR prompts has the potential to greatly improve population health and economic outcomes.

Cost-Effectiveness of Implantable Cardioverter-Defibrillators in Children with Cardiac Conditions Associated with Risk for Sudden Cardiac Death

Children at high risk for sudden cardiac death (SCD) receive implantable cardioverter-defibrillators (ICD) for prevention, but the cost effectiveness of ICDs in children at intermediate risk is unclear. Our objective was to create a cost-effectiveness model to compare costs and outcomes in children at risk of SCD, with and without ICD. Utilizing hypertrophic cardiomyopathy as the proxy disease, a theoretical cohort of 8150 children was followed for 69 years. Model inputs were derived from the literature, with an incremental cost-effectiveness ratio (ICER) willingness-to-pay threshold of $100,000/quality-adjusted life year (QALY) used to delineate cost effectiveness. Outcomes included prevalence of severe neurological morbidity (SNM), SCD, cost, and QALYs. In children at intermediate risk of SCD (4-6% over 5 years), ICD resulted in 56 fewer cases of SNM, 2686 fewer deaths. In children at high risk (> 6% over 5 years), ICD placement resulted in 74 fewer cases of SNM and 3663 fewer deaths from cardiac causes. The costs of ICD were higher, but placement was cost effective with an ICER of $3009 per QALY in intermediate risk children, but ICD therapy was a dominant strategy in high-risk children. Sensitivity analysis demonstrated ICD placement was cost-effective until the annual probability of SCD was < 0.22%. The model was robust over a wide range of values. For children at risk of SCD, prophylactic ICD implantation is cost effective, resulting in improved outcomes and increased QALYs, despite increased costs. These findings highlight the economic benefits of ICD utilization in this population.

Cost-effectiveness of in-home automated external defibrillators for children with cardiac conditions associated with risk of sudden cardiac death

BACKGROUND

Children at high risk for sudden cardiac death (SCD) (>6% over 5 years) receive an implantable cardioverter-defibrillator (ICD), but no guidelines are available for those at lower risk. For children at intermediate risk for SCD (4%-6% over 5 years), the utility and cost-effectiveness of in-home automated external defibrillators (AEDs) are unclear.

OBJECTIVE

The purpose of this study was to assess the cost-effectiveness of in-home AED for children at intermediate risk for SCD.

METHODS

Using hypertrophic cardiomyopathy (HCM) as the proxy disease, a theoretical cohort of 1550 ten-year-old children with HCM was followed for 69 years. Baseline annual risk of SCD was 0.8%. Outcomes were SCD, severe neurologic morbidity (SNM), cost, and quality-adjusted life-years (QALYs). Model inputs were derived from the literature, with a willingness-to-pay threshold of $100,000 per QALY.

RESULTS

Among children at intermediate risk for SCD, in-home AED resulted in 31 fewer cases of SCD but 3 more cases of SNM. There were 319 QALYs gained. Although costs were higher by $28 million, the incremental cost-effectiveness ratio was $86,458, which is below the willingness-to-pay threshold.

CONCLUSION

For children at intermediate risk for SCD and HCM, in-home AED is cost-effective, resulting in fewer deaths and increased QALYS for a cost below the willingness-to-pay threshold. These findings highlight the economic benefits of in-home AED use in this population.

The Case for Drone-assisted Emergency Response to Cardiac Arrest: An Optimized Statewide Deployment Approach

BACKGROUND Despite evidence linking rapid defibrillation to out-of-hospital cardiac arrest (OHCA) survival, bystander use of automatic external defibrillators (AEDs) remains low, due in part to AED placement and accessibility. AED-equipped drones may improve time-to-defibrillation, yet the benefits and costs are unknown.METHODS We designed drone deployment networks for the state of North Carolina using mathematical optimization models to select drone stations from existing infrastructure by specifying the number of stations and the targeted AED arrival time. Expected outcomes were evaluated over the drone's lifespan (4 years). We estimated the following parameters: proportion of OHCAs within a targeted AED delivery time, bystander utilization of AEDs, survival/neurological status, and incremental cost per quality-adjusted life year (QALY).RESULTS Statewide, 16,503 adults aged 18 or older were expected to experience OHCA with an attempted resuscitation over 4 years. Compared to no drone network, all proposed drone networks were expected to improve survival outcomes. For example, assuming 46% of OHCAs have bystanders willing to use an AED, a 500-drone network decreased the median time of defibrillator arrival from 7.7 to 2.7 minutes compared to no drone network. Expected survival rates doubled (24.5% versus 12.3%), resulting in an additional 30,267 QALYs ($858/incremental QALY). If just 4.5% of OHCAs had willing bystanders, 13.8% of victims would have survived. Sensitivity analysis demonstrated that an AED drone network remained cost-effective over a wide range of assumptions.CONCLUSIONS With proper integration into existing systems, large-scale networks for drone AED delivery have the potential to substantially improve OHCA survival rates while remaining cost-effective. Public health researchers should consider advocating for feasibility studies and policy development surrounding drones.

Out-of-Hospital Cardiac Arrest at Home in Japan

Although majority of out-of-hospital cardiac arrests (OHCAs) occur in private residential locations, that is, at home, the details of emergency patients with OHCAs occurring at home have not been sufficiently investigated at the national level. We obtained data of OHCA cases from the All-Japan Utstein Registry, including detailed information of the location of cardiac arrest. Cases of OHCA occurring at home from 2013 to 2015 were included. Patient characteristics and outcomes after OHCA were described based on the location of cardiac arrest. During the 3-year study period, a total of 212,722 cases of OHCA were documented at home (186,219 in detached houses and 26,503 in multiple dwelling houses), and it accounted for 65.0% of all OHCA cases in Japan. The majority of OHCAs occurred in the living room/bedroom (67.7%), followed by the bathroom (12.9%), entrance/corridor (5.3%), and toilet (4.8%). The characteristics of OHCA at home, widely varied by location of cardiac arrest and residence type. The proportion of bystander-initiated cardiopulmonary resuscitations was less than half at all locations and ranged from 27.9% to 47.1%. The proportion of public-access defibrillation was also low regardless of the location of arrest and ranged from 0.0% to 0.2%. Consequently, the proportion of 1-month survival with favorable neurological outcome was low regardless of the location of arrest and ranged from 0.3% to 2.3%. In conclusion, OHCA occurrence at home accounted for approximately 2/3 of all OHCA cases in Japan, but their outcomes were extremely poor regardless of the location of cardiac arrest.

Effective deployment of public-access automated external defibrillators to improve out-of-hospital cardiac arrest outcomes

Out‐of‐hospital cardiac arrest (OHCA) is a major health concern in Japan and other developed countries with aging populations. Improvements in OHCA outcomes require streamlining the chain of survival. Deployment of public‐access automated external defibrillators (PADs) and defibrillation by bystanders is one strategy that may streamline the chain by reducing the time to defibrillation in individuals with shockable rhythms. Although the effectiveness of PAD programs in increasing survival to discharge has been reported, there have been criticisms and concerns about the small population impact, cost‐effectiveness, and potential negative impact on those with nonshockable rhythms. This article reviews relevant literature regarding the effectiveness and concerns regarding PAD for OHCA.

Public-Access Defibrillation and Out-of-Hospital Cardiac Arrest in Japan

BACKGROUND

Early defibrillation plays a key role in improving survival in patients with out-of-hospital cardiac arrests due to ventricular fibrillation (ventricular-fibrillation cardiac arrests), and the use of publicly accessible automated external defibrillators (AEDs) can help to reduce the time to defibrillation for such patients. However, the effect of dissemination of public-access AEDs for ventricular-fibrillation cardiac arrest at the population level has not been extensively investigated.

METHODS

From a nationwide, prospective, population-based registry of patients with out-of-hospital cardiac arrest in Japan, we identified patients from 2005 through 2013 with bystander-witnessed ventricular-fibrillation arrests of presumed cardiac origin in whom resuscitation was attempted. The primary outcome measure was survival at 1 month with a favorable neurologic outcome (Cerebral Performance Category of 1 or 2, on a scale from 1 [good cerebral performance] to 5 [death or brain death]). The number of patients in whom survival with a favorable neurologic outcome was attributable to public-access defibrillation was estimated.

RESULTS

Of 43,762 patients with bystander-witnessed ventricular-fibrillation arrests of cardiac origin, 4499 (10.3%) received public-access defibrillation. The percentage of patients receiving public-access defibrillation increased from 1.1% in 2005 to 16.5% in 2013 (P<0.001 for trend). The percentage of patients who were alive at 1 month with a favorable neurologic outcome was significantly higher with public-access defibrillation than without public-access defibrillation (38.5% vs. 18.2%; adjusted odds ratio after propensity-score matching, 1.99; 95% confidence interval, 1.80 to 2.19). The estimated number of survivors in whom survival with a favorable neurologic outcome was attributed to public-access defibrillation increased from 6 in 2005 to 201 in 2013 (P<0.001 for trend).

CONCLUSIONS

In Japan, increased use of public-access defibrillation by bystanders was associated with an increase in the number of survivors with a favorable neurologic outcome after out-of-hospital ventricular-fibrillation cardiac arrest.

Public-access AED pad application and outcomes for out-of-hospital cardiac arrests in Osaka, Japan

BACKGROUND

Actual application of public-access automated external defibrillator (AED) pads to patients with an out-of-hospital cardiac arrest (OHCA) by the public has been poorly investigated.

METHODS

AED applications, prehospital characteristics, and one-month outcomes of OHCAs occurring in Osaka Prefecture from 2011 to 2012 were obtained from the Utstein Osaka Project registry. Patients with a non-traumatic OHCA occurring before emergency medical service attendance were enrolled. The proportion of AED pads that were applied to the patients' chests by the public and one-month outcomes were analysed according to the location of OHCA.

RESULTS

In total, public-access AED pads were applied to 3.5% of OHCA patients (351/9978) during the study period. In the multivariate analyses, OHCAs that occurred in public places and received bystander-initiated cardiopulmonary resuscitation were associated with significantly higher application of public-access AEDs. Among the patients for whom public-access AED pads were applied, 29.6% (104/351) received public-access defibrillation. One-month survival with a favourable neurological outcome was significantly higher among patients who had an AED applied compared to those who did not (19.4% vs. 3.0%; OR: 2.76 [95% CI: 1.92-3.97]).

CONCLUSION

The application of public-access AEDs leads to favourable outcomes after an OHCA, but utilisation of available equipment remains insufficient, and varies considerably according to the location of the OHCA event. Alongside disseminating public-access AEDs, further strategic approaches for the deployment of AEDs at the scene, as well as basic life support training for the public are required to improve survival rates after OHCAs.

Wearable cardioverter-defibrillator for prevention of sudden cardiac death after infected implantable cardioverter-defibrillator removal: A cost-effectiveness evaluation

BACKGROUND

Prevention of sudden cardiac arrest (SCA) after removal of an infected implantable cardioverter-defibrillator (ICD) is a challenging clinical dilemma. The cost-effectiveness of the wearable cardioverter-defibrillator (WCD) in this setting remains uncertain.

OBJECTIVE

The purpose of this study was to compare the cost-effectiveness of the WCD with discharge home, discharge to a skilled nursing facility, or inpatient monitoring for the prevention of SCA after infected ICD removal.

METHODS

A decision model was developed to compare the cost-effectiveness of use of the WCD to several different strategies for patients who undergo ICD removal. One-way and 2-way sensitivity analyses were performed to account for uncertainties.

RESULTS

In the base-case analysis, the incremental cost-effectiveness of the WCD strategy was $20,300 per life-year (LY) or $26,436 per quality-adjusted life-year (QALY) compared to discharge home without a WCD. Discharge to a skilled nursing facility and in-hospital monitoring resulted in higher costs and worse clinical outcomes. The incremental cost-effectiveness ratio was as low as $15,392/QALY if the WCD successfully terminated 95% of SCA events and exceeded the $50,000/QALY willingness-to-pay threshold if the efficacy was <69%.The WCD strategy remained cost-effective, assuming 5.6% 2-month SCA risk, as long as the time to reimplantation was at least 2 weeks.

CONCLUSION

The WCD likely is cost-effective in protecting patients against SCA after infected ICD removal while waiting for ICD reimplantation compared to keeping patients in the hospital or discharging them home or to a skilled nursing facility.

Economic evaluation of using a genetic test to direct breast cancer chemoprevention in white women with a previous breast biopsy

BACKGROUND

Tamoxifen therapy reduces the risk of breast cancer but increases the risk of serious adverse events including endometrial cancer and thromboembolic events.

OBJECTIVES

The cost effectiveness of using a commercially available breast cancer risk assessment test (BREVAGen™) to inform the decision of which women should undergo chemoprevention by tamoxifen was modeled in a simulated population of women who had undergone biopsies but had no diagnosis of cancer.

METHODS

A continuous time, discrete event, mathematical model was used to simulate a population of white women aged 40-69 years, who were at elevated risk for breast cancer because of a history of benign breast biopsy. Women were assessed for clinical risk of breast cancer using the Gail model and for genetic risk using a panel of seven common single nucleotide polymorphisms. We evaluated the cost effectiveness of using genetic risk together with clinical risk, instead of clinical risk alone, to determine eligibility for 5 years of tamoxifen therapy. In addition to breast cancer, the simulation included health states of endometrial cancer, pulmonary embolism, deep-vein thrombosis, stroke, and cataract. Estimates of costs in 2012 US dollars were based on Medicare reimbursement rates reported in the literature and utilities for modeled health states were calculated as an average of utilities reported in the literature. A 50-year time horizon was used to observe lifetime effects including survival benefits.

RESULTS

For those women at intermediate risk of developing breast cancer (1.2-1.66 % 5-year risk), the incremental cost-effectiveness ratio for the combined genetic and clinical risk assessment strategy over the clinical risk assessment-only strategy was US$47,000, US$44,000, and US$65,000 per quality-adjusted life-year gained, for women aged 40-49, 50-59, and 60-69 years, respectively (assuming a price of US$945 for genetic testing). Results were sensitive to assumptions about patient adherence, utility of life while taking tamoxifen, and cost of genetic testing.

CONCLUSIONS

From the US payer's perspective, the combined genetic and clinical risk assessment strategy may be a moderately cost-effective alternative to using clinical risk alone to guide chemoprevention recommendations for women at intermediate risk of developing breast cancer.

Role of wearable and automatic external defibrillators in improving survival in patients at risk for sudden cardiac death

Cardiac arrest is a vexing public health problem. Fortunately, implantable cardioverter-defibrillators (ICDs) have been proven to decrease overall mortality in several populations at high risk for cardiac arrest. However, it is still unclear how to treat patients who have an elevated risk of cardiac arrest but are not in one of the identified high-risk groups proven to benefit from an ICD. It also is uncertain how to manage high-risk patients who have an accepted indication for an ICD but are unable or unwilling to have an ICD. In these clinical situations, the wearable defibrillator and automatic external defibrillator are options that should be considered. Both devices have been shown in small series to be highly effective at restoring sinus rhythm in patients with a ventricular tachyarrhythmia. However, there is still a lack of large-scale trials proving that these devices should be employed routinely in specific high-risk patient populations.

Location of cardiac arrest in a city center: strategic placement of automated external defibrillators in public locations

BACKGROUND

Public-access defibrillation with automated external defibrillators (AEDs) is being implemented in many countries worldwide with considerable financial implications. The potential benefit and economic consequences of focused or unfocused AED deployment are unknown.

METHODS AND RESULTS

All cardiac arrests in public in Copenhagen, Denmark, from 1994 through 2005 were geographically located, as were 104 public AEDs placed by local initiatives. In accordance with European Resuscitation Council and American Heart Association (AHA) guidelines, areas with a high incidence of cardiac arrests were defined as those with 1 cardiac arrest every 2 or 5 years, respectively. There were 1274 cardiac arrests in public locations. According to the European Resuscitation Council or AHA guidelines, AEDs needed to be deployed in 1.2% and 10.6% of the city area, providing coverage for 19.5% (n=249) and 66.8% (n=851) of all cardiac arrests, respectively. The excessive cost of such AED deployments was estimated to be $33 100 or $41 000 per additional quality-adjusted life year, whereas unguided AED placement covering the entire city had an estimated cost of $108 700 per quality-adjusted life year. Areas with major train stations (1.8 arrests every 5 years per area), large public squares, and pedestrianized areas (0.6 arrests every 5 years per area) were main predictors of frequent cardiac arrests.

CONCLUSIONS

To achieve wide AED coverage, AEDs need to be more widely distributed than recommended by the European Resuscitation Council guidelines but consistent with the American Heart Association guidelines. Strategic placement of AEDs is pivotal for public-access defibrillation, whereas with unguided initiatives, AEDs are likely to be placed inappropriately.

Assessing automated external defibrillators in preventing deaths from sudden cardiac arrest: An economic evaluation

Objectives:The aim of this study was to evaluate the cost-effectiveness of on-site automated external defibrillators (AEDs) in the initial management of cardiac arrest in Ontario.

Methods:This was a cost-effectiveness analysis based on published literature and data from the Canadian Institute of Health Information. The participants were fictitious male and female cardiac arrest patients who were initially managed with on-site AEDs, compared with similar patients managed without on-site AEDs. This group included a subgroup of high-risk patients (i.e., heart failure and left ventricular ejection fraction <35 percent). The analysis was conducted in a variety of settings including hospitals and homes in Ontario, Canada. The main outcome evaluated was cost per quality-adjusted life-year (QALY) gained from a payer's perspective.

Results:Cost per QALY (all costs reported in Canadian dollars) was $12,768 when AEDs were deployed in hospitals, $511,766 when deployed in office buildings, $2,360,023 when deployed in apartment buildings, $87,569 when deployed in homes of high-risk patients, and $1,529,371 when deployed in homes of people older than 55 years of age.

Conclusions:Indiscriminate deployment of AEDs is not a cost-effective means of improving health outcomes of cardiac arrest. Their use should be restricted to emergency response programs, high-risk sites (such as hospitals), and high-risk patients.

Cost-effectiveness of automated external defibrillators in public places: con

PURPOSE OF REVIEW

To discuss the clinical effectiveness, public health impact and cost-effectiveness of public access defibrillation.

RECENT FINDINGS

High rates of survival from prehospital ventricular fibrillation have been documented in patients treated by first responders using automated external defibrillators. The recent Public Access Defibrillation trial demonstrated a doubling of cardiac arrest survival in community units where volunteers trained in cardiopulmonary resuscitation were additionally equipped with automated external defibrillators. The cost-effectiveness analysis of the Public Access Defibrillation trial has not yet been published, and previous analyses have lacked full data on cost, outcome, or both. Data from many sources indicate that automated external defibrillator placement at sites with an expected rate of one cardiac arrest per defibrillator per 5 years, as recommended by the American Heart Association, addresses only around 1-2% of prehospital arrests, and will have a minimal impact on population survival.

SUMMARY

While highly targeted provision of automated external defibrillators in areas of greatest risk, such as casinos and airports, may be cost-effective, it will have little impact at a population level. Provision of more widespread public access defibrillation to sites with lower incidence of cardiac arrest is unlikely to be cost-effective, and may represent poorer value for money than alternative healthcare interventions in coronary artery disease.

Implantable or external defibrillators for individuals at increased risk of cardiac arrest: where cost-effectiveness hits fiscal reality

OBJECTIVES

Implantable cardioverter defibrillators (ICDs) are highly effective at preventing cardiac arrest, but their availability is limited by high cost. Automated external defibrillators (AEDs) are likely to be less effective, but also less expensive. We used decision analysis to evaluate the clinical and economic trade-offs of AEDs, ICDs, and emergency medical services equipped with defibrillators (EMS-D) for reducing cardiac arrest mortality.

METHODS

A Markov model was developed to compare the cost-effectiveness of three strategies in adults meeting entry criteria for the MADIT II Trial: strategy 1, individuals experiencing cardiac arrest are treated by EMS-D; strategy 2, individuals experiencing cardiac arrest are treated with an in-home AED; and strategy 3, individuals receive a prophylactic ICD. The model was then used to quantify the aggregate societal benefit of these three strategies under the conditions of a constrained federal budget.

RESULTS

Compared with EMS-D, in-home AEDs produced a gain of 0.05 quality-adjusted life-years (QALYs) at an incremental cost of $5225 ($104,500 per QALY), while ICDs produced a gain of 0.90 QALYs at a cost of $114,660 ($127,400 per QALY). For every $1 million spent on defibrillators, 1.7 additional QALYs are produced by purchasing AEDs (9.6 QALYs/$million) instead of ICDs (7.9 QALYs/$million). Results were most sensitive to defibrillator complication rates and effectiveness, defibrillator cost, and adults' risk of cardiac arrest.

CONCLUSIONS

Both AEDs and ICDs reduce cardiac arrest mortality, but AEDs are significantly less expensive and less effective. If financial constraints were to lead to rationing of defibrillators, it might be preferable to provide more people with a less effective and less expensive intervention (in-home AEDs) instead of providing fewer people with a more effective and more costly intervention (ICDs).

Use of automated external defibrillators in cardiac arrest: an evidence-based analysis

OBJECTIVE

The objectives were to identify the components of a program to deliver early defibrillation that optimizes the effectiveness of automated external defibrillators (AEDs) in out-of-hospital and hospital settings, to determine whether AEDs are cost-effective, and if cost-effectiveness was determined, to advise on how they should be distributed in Ontario.

CLINICAL NEED

Survival in people who have had a cardiac arrest is low, especially in out-of-hospital settings. With each minute delay in defibrillation from the onset of cardiac arrest, the probability of survival decreases by 10%. (1) Early defibrillation (within 8 minutes of a cardiac arrest) has been shown to improve survival outcomes in these patients. However, in out-of-hospital settings and in certain areas within a hospital, trained personnel and their equipment may not be available within 8 minutes. This implies that "first responders" should take up the responsibility of delivering shock. The first responders in out-of-hospital settings are usually bystanders, firefighters, police, and community volunteers. In hospital settings, they are usually nurses. These first responders are not trained in reading electrocardiograms and identifying abnormal heart rhythms restorable by defibrillation.

THE TECHNOLOGY

An AED is a device that can analyze a heart rhythm and deliver a shock if needed. Thus, AEDs can be used by first responders to deliver early defibrillation in out-of-hospital and hospital settings. However, simply providing an AED would not likely improve survival outcomes. Rather, AEDs have a role in strengthening the "chain of survival," which includes prompt activation of the 911 telephone system, early cardiopulmonary resuscitation (CPR), rapid defibrillation, and timely advanced life support. In the chain of survival, the first step for a witness of a cardiac arrest in an out-of-hospital setting is to call 911. Second, the witness initiates CPR (if she or he is trained in CPR). If the witness cannot initiate CPR, or the first responders of the 911 system (e.g., firefighters/police) have arrived, the first responders initiate CPR. Third, the witness or first responders apply an AED to the patient. The device reads the patient's heart rhythm and prompts for shock when indicated. Fourth, the patient is handed over to the advanced life-support team with subsequent admission to an intensive care unit in a hospital. The use of AEDs requires developing and implementing a program at sites where the cardiac arrest rate is high, where a number of potential first responders are trained and retained, and where patients are transferred to an advanced care facility after initiating resuscitation. Obviously, placing an AED at a site where no cardiac arrests are likely to occur would be futile, as would placing an AED at a site where no one knows how to use it. Moreover, abandoning patients after initial resuscitation by not transferring them to an advanced care facility would negate all earlier efforts. Thus, it is important to identify the essential components of an AED program that might also optimize the effectiveness of AED use.

METHODS

There is a large body of literature on the use of AEDs in various settings ranging from closed environments such as hospitals, airlines, and casinos to open places such as sports fields and highways. There is little doubt regarding the effectiveness and safety of AEDs to treat people in cardiac arrest. It is intuitive that these devices should be provided in hospitals in areas that are not readily accessible to the traditional responders, the "code blue team." Similarly, it is intuitive to provide AEDs in out-of-hospital settings where the risk of cardiac arrest is high and a response plan involving trained first responders in the use of AEDs is in place. Thus, the Medical Advisory Secretariat reviewed the literature and focused on the components of an AED program in out-of-hospital settings that maximize the effectiveness and cost-effectiveness of the program in the management of cardiac arrest. Search engines included MEDLINE, EMBASE, EconLit and Web sites of other agencies that assess health technologies. Any study that reported results of an AED program in an out-of-hospital setting was included. Studies that did not use AEDs, had a physician-assisted emergency response plan, did not have a program for the use of AEDs, or did not include cardiac arrest as an outcome were excluded.

SUMMARY OF FINDINGS

A total of 133 articles were identified; 62 were excluded after reviewing titles and abstracts. Of the 71 articles reviewed, 8 reported findings of 2 large studies, the Ontario Prehospital Advanced Life Support (OPALS) study and the Public Access Defibrillation (PAD) trial. These studies examined the effect of a community program to respond to cardiac arrest with and without the use of AEDs. Their authors had reported a significant reduction in overall mortality from cardiac arrest with the use of AEDs. Factors That Improve the Effectiveness of an AED Program The PAD trial investigators reported a significant improvement in survival (P = .03) after providing AEDs in public access areas and training volunteers in CPR compared with training volunteers in CPR only. The OPALS study investigators reported odds ratios (ORs) and 95% confidence intervals (CIs) for significant predictors of survival, which were age (OR [age per 10 year], 0.8; CI, 0.8-0.9), arrest witnessed by bystander (OR, 3.9; CI, 2.7-5.5), CPR initiated by bystander (OR, 3.7; CI, 2.6-5.1), CPR initiated by first responder (OR, 1.6; CI, 1.1-2.3), and emergency medical service response within 8 minutes (OR, 3.0; CI, 1.8-5.1). The last 3 variables are modifiable and thus may improve the effectiveness of an AED program. For example, the rate of bystander-initiated CPR was only 14% in the OPALS study, but it was 100% in the PAD trial. This was because PAD trial investigators trained community volunteers whereas the OPALS study investigators did not. Cost-Effectiveness A systematic review of the literature suggests that cost-effectiveness varies from setting to setting. Most of the studies have estimated cost-effectiveness in American settings from a societal perspective; therefore, the results are not applicable to this report. However, results from this review suggest that the incidence of cardiac arrest in out-of-hospital setting in Ontario is 59 per 100,000 people. The mean age of cardiac arrest patients is 69 years. Eighty-five percent of these cardiac arrests occur in homes. Of all the cardiac arrests, 37% have heart rhythm abnormalities (ventricular tachycardia or ventricular fibrillation) that are correctable by delivering shock through an AED. Thus, in an out-of-hospital setting, general use of AEDs by laypersons would not be cost-effective. Special programs are needed in the out-of-hospital setting for cost-effective use of AEDs. One model for the use of AEDs in out-of-hospital settings was examined in the OPALS study. Firefighters and police were trained and provided with AEDs. The total initial cost (in US dollars) of this program was estimated to be $980,000. The survival rate was 3.9% before implementing the AED program and 5.2% after its implementation (OR, 1.33; 95% CI, 1.03-1.7; P = .03). Applying these estimates to cardiac arrest rates in Ontario in 2002, one would expect 54 patients of the total 1,395 cardiac arrests to survive without AEDs compared with 73 patients with AEDs; thus, 19 additional lives might be saved each year with an AED program. It would initially cost $51,579 to save each additional life. In subsequent years, however, total cost would be lower (about $50,000 per year), when it would cost $2,632 to save each additional life per year. One limitation of the OPALS study was that the authors combined emergency medical service response time and application of an AED into a single variable. Thus, it was not possible to tease out the independent effects of reduction in response time and application of an AED on the small improvement in survival. Nevertheless, the PAD study found that when response time was fixed, the application of AED improved survival. There are other delivery models for AEDs in casinos, sports arenas, and airports. The proportion of cardiac arrest at these sites out of the total cardiac arrests in Ontario is between 0.05% and 0.4%. Thus, an AED placed at these sites would likely not be used at all. Of the 85% cardiac arrests that occur in homes, 56% occur in single residential dwellings (houses), 23% occur in multi-residential dwellings (apartments/condominiums), and 6% occur in nursing homes. There is no program in place except the 911 system to reach these patients. Accordingly, the Medical Advisory Secretariat examined the cost-effectiveness of providing AEDs in hospitals, office buildings, apartments/condominiums, and houses. The results suggested that deployment of AEDs in hospitals would be cost-effective in terms of cost per quality adjusted life year gained. Conversely, deployment of AEDs in office buildings, apartments, and houses was not cost-effective. An exception, however, was noted for people at high risk of sudden cardiac arrest; these were patients with a left ventricular ejection fraction less than or equal to 0.35.

CONCLUSIONS

The OPALS study model appears cost-effective, and effectiveness can be further enhanced by training community volunteers to improve the bystander-initiated CPR rates. Deployment of AEDs in all public access areas and in houses and apartments is not cost-effective. Further research is needed to examine the benefit of in-home use of AEDs in patients at high risk of cardiac arrest.