Using administrative databases in the surveillance of depressive disorders--case definitions

The objective of this study was to assess the usefulness of provincial administrative databases in carrying out surveillance on depressive disorders. Electronic medical records (EMRs) at 3 family practice clinics in St. John's, NL, Canada, were audited; 253 depressive disorder cases and 257 patients not diagnosed with a depressive disorder were selected. The EMR served as the "gold standard," which then was compared to these same patients investigated through the use of various case definitions applied against the provincial hospital and physician administrative databases. Variables used in the development of the case definitions were depressive disorder diagnoses (either in hospital or physician claims data), date of diagnosis, and service provider type [general practitioner (GP) vs. psychiatrist]. Of the 120 case definitions investigated, 26 were found to have a kappa statistic greater than 0.6, of which 5 case definitions were considered the most appropriate for surveillance of depressive disorders. Of the 5 definitions, the following case definition, with a 77.5% sensitivity and 93% specificity, was found to be the most valid ([ ≥1 hospitalizations OR ≥1 psychiatrist visit related to depressive disorders any time] OR ≥2 GP visits related to depressive disorders within the first 2 years of diagnosis). This study found that provincial administrative databases may be useful for carrying out surveillance on depressive disorders among the adult population. The approach used in this study was simple and resulted in rather reasonable sensitivity and specificity.