Ambulance calls to suspected overdoses: New South Wales patterns July 1997 to June 1999

AIM: Using data on New South Wales ambulance calls to suspected overdoses from July 1997 to June 1999 to: a) examine temporal and geographic trends in calls; and b) compare geographic patterns of fatal and non-fatal opioid overdose. METHOD: The NSW Ambulance Service provided data on the occasions when an ambulance attended a person on whom the drug overdose/poisonings protocol was used, and to whom naloxone was administered. The geographic distribution of ambulance attendances was approximated to the Australian Bureau of Statistics Statistical Local Area (SLA) and Statistical Subdivision (SSD). Estimates of social disadvantage were correlated with the rate of ambulance attendances for each region. RESULTS: 9,116 callouts were made. In cases with data on age and gender, 89% were aged 15-44 years, and 31% were female. South Sydney (n=1,819) and Liverpool (n=1,602) SLAs accounted for 37% of calls; the higher rates outside Sydney were in Newcastle, Orange and Kiama. There was a strong correlation between rates of ambulance callouts and fatal heroin overdoses. The number of calls increased from an average of 361 calls per month in 1997-98 to 399 in 1998-99. The majority of calls (54%) were made between midday and 9 pm. CONCLUSIONS: Rates of ambulance attendance at suspected overdoses is a promising indicator that allows monitoring of trends and identification of areas with high rates of opioid use.