Study objective-To determine the distribution of opioid use prevalence in s
mall areas and its relation with socioeconomic indicators.
Design-Capture-recapture was applied using data from the Barcelona Drug Inf
ormation System for 1993 (treatment demands, hospital emergency room visits
, deaths from heroin acute adverse reaction and pre-trial prison admissions
). To avoid dependence between sources, a log-linear regression model with
interactions was fitted. For small neighbourhoods, where capture-recapture
estimates were not obtainable, the Heroin Problem Index (HPI) was used to p
redict prevalence rates from a regression model. The correlation between es
timated opioid use prevalence by neighbourhoods and their socioeconomic lev
el was computed.
Main results-The city's estimated prevalence was 12.9 opioid addicts per 10
00 inhabitants aged 15 to 44 years (95% CI:10.1, 17.2), which represents 91
76 persons. The highest rate was found in the inner city neighbourhood. Com
paring rates obtained for each neighbourhood with their unemployment rates,
a high correlation coefficient was obtained (r = 0.80, p < 0.001).
Conclusion-The main contribution of this study is that of combining capture
-recapture with the HPI to produce small area prevalence estimates, which w
ould not have been possible using only one method. Areas with higher socioe
conomic status showed proportionally low addiction prevalences, but in depr
essed areas, prevalences varied widely.