Population Density, Call-Response Interval, and Survival of Out-Of-Hospital Cardiac Arrest

Int J Health Geogr. 2011 Apr 14;10:26. doi: 10.1186/1476-072X-10-26.

Abstract

Background: Little is known about the effects of geographic variation on outcomes of out-of-hospital cardiac arrest (OHCA). The present study investigated the relationship between population density, time between emergency call and ambulance arrival, and survival of OHCA, using the All-Japan Utstein-style registry database, coupled with geographic information system (GIS) data.

Methods: We examined data from 101,287 bystander-witnessed OHCA patients who received emergency medical services (EMS) through 4,729 ambulatory centers in Japan between 2005 and 2007. Latitudes and longitudes of each center were determined with address-match geocoding, and linked with the Population Census data using GIS. The endpoints were 1-month survival and neurologically favorable 1-month survival defined as Glasgow-Pittsburgh cerebral performance categories 1 or 2.

Results: Overall 1-month survival was 7.8%. Neurologically favorable 1-month survival was 3.6%. In very low-density (<250/km(2)) and very high-density (≥10,000/km(2)) areas, the mean call-response intervals were 9.3 and 6.2 minutes, 1-month survival rates were 5.4% and 9.1%, and neurologically favorable 1-month survival rates were 2.7% and 4.3%, respectively. After adjustment for age, sex, cause of arrest, first aid by bystander and the proportion of neighborhood elderly people ≥65 yrs, patients in very high-density areas had a significantly higher survival rate (odds ratio (OR), 1.64; 95% confidence interval (CI), 1.44 - 1.87; p < 0.001) and neurologically favorable 1-month survival rate (OR, 1.47; 95%CI, 1.22 - 1.77; p < 0.001) compared with those in very low-density areas.

Conclusion: Living in a low-density area was associated with an independent risk of delay in ambulance response, and a low survival rate in cases of OHCA. Distribution of EMS centers according to population size may lead to inequality in health outcomes between urban and rural areas.

Publication types

  • Comparative Study
  • Multicenter Study

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cardiopulmonary Resuscitation / standards
  • Cardiopulmonary Resuscitation / trends
  • Emergency Medical Services / standards*
  • Emergency Medical Services / trends
  • Female
  • Humans
  • Male
  • Middle Aged
  • Out-of-Hospital Cardiac Arrest / mortality*
  • Out-of-Hospital Cardiac Arrest / therapy*
  • Population Density*
  • Prospective Studies
  • Registries
  • Survival Rate / trends
  • Time Factors
  • Treatment Outcome