Elsevier

Resuscitation

Volume 84, Issue 8, August 2013, Pages 1099-1107
Resuscitation

Clinical paper
Regional variability in survival outcomes of out-of-hospital cardiac arrest: The All-Japan Utstein Registry

https://doi.org/10.1016/j.resuscitation.2013.03.007Get rights and content

Abstract

Objective

There is a paucity of studies on the degree of regional variability in out-of-hospital cardiac arrest (OHCA) outcomes, particularly in neurological outcome. This study aimed to determine whether there is a significant regional variation in survival outcomes of OHCA across Japan.

Methods

We analyzed a prospective, nation-wide, population-based database (All-Japan Utstein Registry) involving all Japanese individuals who had non-traumatic OHCA resuscitated by emergency responders from January 2005 through December 2010. The primary study endpoint was favourable neurological survival at 1 month, defined as Cerebral Performance Category 1 or 2. We compared unadjusted and multivariable-adjusted rates of the outcome among seven geographic regions.

Results

In the total catchment population of 128 million, there were 539,641 non-traumatic OHCA patients. Unadjusted neurologically favourable survival varied across regions from 1.9% to 3.1% (rate difference, 1.2%; 95%CI, 1.0–1.3%); the Northeast region had a significantly lower rate compared to the Midwest region (unadjusted rate ratio, 0.62; 95%CI, 0.60–0.64). This disparity became larger after adjusting for patient- and prehospital-level confounders (adjusted rate ratio, 0.52; 95%CI, 0.51–0.54). Among 35,153 OHCA patients with return of spontaneous circulation, unadjusted neurologically favourable survival varied from 26.4% to 34.7% (rate difference, 8.3%; 95%CI, 6.6–10.1%); the East region had a significantly lower rate compared to the Midwest region (adjusted rate ratio, 0.72; 95%CI, 0.68–0.76).

Conclusion

In this prospective, nation-wide, population-based study in Japan, we found a two-fold regional difference in neurologically favourable survival after OHCA, suggesting regional disparities in prehospital care and in-hospital post-resuscitation care.

Introduction

Sudden death from cardiac arrest remains a major public health problem that affects 275,000 individuals in Europe,1 and 375,000–390,000 people in the United States each year.2 Despite its significance, there has been little improvement in out-of-hospital cardiac arrest (OHCA) survival.3, 4 In contrast, implementation of regional systems of care for those with acute myocardial infarction and trauma has improved outcomes.5, 6 Likewise, OHCA is also a primarily community-specific problem. Yet, few communities have developed regional systems of care for OHCA victims and achieved sustained improvements in survival.3, 4, 7

Accurate estimation of the regional burden of OHCA is essential to evaluate progress of cardiovascular disease prevention programmes. In addition, knowledge of regional variability in long-term survival outcomes after cardiac arrest could identify gaps, highlight key areas of improvement, and guide concentration on improving long-term outcomes by focusing on locally identified problem areas within the “chain of survival.” North American studies have reported regional variations in unadjusted survival to hospital discharge after OHCA.8, 9, 10, 11, 12 Additionally, studies from Sweden documented an interhospital variation in 1-month survival after successful resuscitation.13, 14 However, these studies only inferred patient-centred outcomes, such as neurological status, from survival to discharge; the sites were not sampled to reflect the entire population. Furthermore, there is a paucity of studies on OHCA outcome variation in the rest of the world. Regional variations in outcomes of OHCA, which inform estimates of preventable deaths and disabilities and suggest uneven delivery of resuscitation care, remain to be determined. In this context, we sought to determine if there is significant regional variation in the survival outcomes of OHCA across Japan.

Section snippets

Study design and participants

The All-Japan Utstein registry of the Fire and Disaster Management Agency (FDMA) is a prospective, nation-wide, population-based registry system of OHCAs in infants, children, and adults, with Utstein-style data collection.15 All patients who had had OHCA and for whom resuscitation was attempted by emergency medical service (EMS) personnel with subsequent transport to medical institutions from January 1, 2005, to December 31, 2010, were eligible for our analysis. Cardiac arrests with unknown

Patient and prehospital care characteristics

In the total catchment population of 128 million, 670,313 OHCAs were documented (Fig. 1). Of 660,672 resuscitation attempts, 120,973 arrests with external causes and 58 arrests with unknown age were excluded, leaving 539,641 arrests eligible for analysis.

Patient and prehospital care characteristics for the eligible OHCA patients by geographic region are shown in Table 1. Regions had a median catchment population of 14,596,783 (range, 5,506,419–47,994,059), with a median population density was

Discussion

In this prospective, nation-wide, population-based study of Japanese patients with out-of-hospital cardiac arrest, we found that the OHCA incidence, favourable neurological survival, and 1-month survival differed significantly across geographic regions. The significant variations in the survival outcomes persisted even after adjustment for various patient- and prehospital-level factors, and in the subgroup analysis for the patients who achieved return of spontaneous circulation. Our findings

Limitations

This study should be interpreted in the context of the following limitations. First, as with any observational study, confounding variables may have affected our inference. Despite a rigorous adjustment for a number of patient factors (e.g., age, aetiology of arrest, and initial cardiac rhythm) and prehospital care variables, there are other socioeconomic, circumstantial, and inhospital post-arrest care variables as well as underlying comorbidities that may have contributed to the observed

Conclusions

In this prospective, nation-wide, population-based study in Japan, we found a two-fold regional difference in neurologically favourable survival after OHCA, suggesting regional disparities in prehospital care and in-hospital post-resuscitation care. Organized community efforts addressing both components are warranted.

Conflict of interest statement

None declared.

Financial support

This study was supported in part by the grant for emergency management scientific research from the Fire and Disaster Management Agency (to Dr Hiraide, on behalf of the study group concerning strategy for applying the results of Utstein report for improvement of emergency service). The Fire and Disaster Management Agency gathered and managed the data but had no role in the design and conduct of the study; analysis and interpretation of the data; and preparation, review, or approval of the

Acknowledgements

We are greatly indebted to all the emergency medical service personnel and concerned physicians in Japan, and to the Fire and Disaster Management Agency and Institute for Fire Safety and Disaster Preparedness of Japan for their generous co-operation in establishing and maintaining the Utstein database. We also thank Long H. Ngo, PhD, for the statistical analyses.

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    A Spanish translated version of the abstract of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2013.03.007.

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