[Classification of illicit drug-induced deaths in Spain: toward the adoption of the European standard criteria].

AIMS To describe patterns of ICD-10 classification of illicit drug-induced deaths (DID) in the General Mortality Register (GMR), to assess the applicability of the European criterion (which excludes the X44 code) to extract these deaths from the GMR, and to estimate drug-induced mortality in Spain by applying a correction index for underestimation. METHODS DID between 1999 and 2007 were extracted from the GMR using the European and the Spanish criteria. Both data sets were compared, and differences in classification patterns by time and space were assessed. Estimations of national mortality from DID were calculated by applying a correction index for underestimation, derived from a specific mortality register, to the deaths extracted from the GMR. RESULTS Using the Spanish criterion, 5,878 DID were extracted from the GMR for 1999-2007, 88.4% within chapter XX, mainly X42 (48.4%) and X44 (38.8%), and the remaining within chapter V, mainly F19 (11.5%). Chapter V accounted for 6.6% in 1999, 24.6% in 2003 and 8.0% in 2007. Between 2005 and 2007, Catalonia and Andalusia were the autonomous regions showing greatest use of this chapter (34.9% and 30.1%, respectively). Substantially fewer deaths were extracted when the European criterion was used. When the Spanish indicator was used, the estimated DID mortality rate corrected by the underestimation index decreased slowly from 4.7/100,000 in 1999 to 4.1/100,000 inhabitants aged 15-49 years old in 2007. CONCLUSIONS In Spain, applying the European criterion for extracting DID from the GMR created certain problems, because each DID is assigned a single code, which is sometimes non-specific. Common national criteria should be adopted, following the European criteria as far as possible.