Fluctuations in heroin purity and the incidence of fatal heroin overdose

In order to determine the role played by heroin purity in fatal heroin over doses, time series analyses were conducted on the purity of street heroin s eizures in south western Sydney and overdose fatalities in that region. A t otal of 322 heroin samples were analysed in fortnightly periods between Feb ruary 1993 to January 1995. A total of 61 overdose deaths occurred in the r egion in the study period. Cross correlation plots revealed a significant c orrelation of 0.57 at time lag zero between mean purity of heroin samples p er fortnight and number of overdose fatalities. Similarly, there was a sign ificant correlation of 0.50 at time lag zero between the highest heroin pur ity per fortnight and number of overdose fatalities. The correlation betwee n range of heroin purity and number of deaths per fortnight was 0.40. A sim ultaneous multiple regression on scores adjusted for first order correlatio n indicated both the mean level of heroin purity and the range of heroin pu rity were independent predictors of the number of deaths per fortnight. The results indicate that the occurrence of overdose fatalities was moderately associated with both the average heroin purity and the range of heroin pur ity over the study period. (C) 1999 Elsevier Science Ireland Ltd. All right s reserved.