Adverse outcomes of GHB use: Analysis of ambulance attendances in metropolitan and regional Victoria.

BACKGROUND: Gamma-hydroxybutyrate (GHB) use and attributable harms have been increasing in Australia, however changes over time, including the impact of COVID-19 lockdowns and restrictions on harms requiring an ambulance attendance, are unknown. This study utilised a novel population-based surveillance system to identify the types of GHB-related harms between January 2018 and 31 December 2021 in Victoria, Australia. METHODS: A cross-sectional, retrospective analysis of all GHB-related ambulance attendances between January 2018 and 31 December 2021 in Victoria, Australia was undertaken. Paramedic clinical notes and Glasgow Coma Scale scores were used to assess conscious state. Event codes were classified using dispatch information available in the database. Crude rates (per 100,000 population) and descriptive analyses were calculated for metropolitan and regional settings. Adjusted Odds ratios (aOR) with 95% confidence intervals [95% CI] were used to assess the relationship between GCS severity and polysubstance combinations with GHB. RESULTS: There were 6,836 ambulance attendances for GHB recorded during the study period. A statistically significant increase in GHB-related attendance numbers was observed State-wide in 2019 (n = 1,402, p<0.001) and 2020 (n = 2,622, p<0.001), when comparing year on year attendances. While both numbers and rates (per 100,000 population) of GHB-related attendances were significantly lower in regional areas, significant increases were evident in both metropolitan and regional areas in 2019 and 2020 (both p<0.001). Attendances involving GHB and alcohol had higher odds of a severe GCS score (aOR:1.25; 95%: 1.04-1.49; p<0.019). A high proportion of GHB-attendances involved harms of significant concern including: overdose (56%) and a loss of, or altered state of consciousness (45%). CONCLUSIONS: We observed increases in GHB-related ambulance attendances over time in both metropolitan and regional areas, placing a significant burden on ambulance services. Our study demonstrates the value of using ambulance surveillance to obtain representative data on acute GHB-related harms.