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Evaluating the usefulness of human health databases in the surveillance of zoonotic, enteric disease in Alberta. Jane Parmley Department of Population Medicine Ontario Veterinary College. Background .
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Evaluating the usefulness of human health databases in the surveillance of zoonotic, enteric disease in Alberta Jane Parmley Department of Population Medicine Ontario Veterinary College
Background • An apparent high rate of enteric disease was identified in Southern Alberta through routine analysis of the provincial notifiable disease registry
Thesis Questions • Is there a problem? • What is the problem? • Where is the problem?
Thesis objectives • Perform descriptive analyses on four human health databases from Alberta and compare among them • Select a group of controls and compare the geographic and temporal distributions with the cases • Identify risk factors for entry into each of the databases
Thesis material and methods • Databases: • Notifiable Disease Registry • Hospital Discharge Dataset (CIHI) • Physician Visit Dataset (AHCIP) • Emergency Dataset (AHCIP)
Population: • Canada census 1996a • Geographic areas: • Canada census 1996a and Postal code conversion filea • Risk factor data: • Canada census 1996a • Canada census of agriculture 1996a • Water distribution in Albertab • Other aStatistics Canada bFoodborne, Waterborne and Zoonotic Infections Division (CIDPC-Health Canada) and Alberta Ministry of Environment.
Some preliminary findings • The distribution of cases between databases was very different • The distribution of cases and controls within individual databases were very similar
Case distribution by database NDR case CIHI case PV case EMRG case
Rank correlation coefficients between datasets • Significant correlations: • NDR and PV r=0.40 • CIHI and EMRG r=0.39 • PV and EMRG r=0.36 • No correlation between: • NDR and CIHI • NDR and EMRG • CIHI and PV
Case and control distribution CIHI control CIHI case PV control PV case
Rank correlation coefficients between cases and controls • Significant correlations: • CIHI r=0.73 • PV r=0.72 • EMRG r=0.82
So which database should we use for surveillance of zoonotic, enteric pathogens in Alberta?
Why are they different? • Healthcare availability? The nature of disease reporting • Case definition? • Sensitivity of the diagnostic codes • Database objectives? • Surveillance vs administration
Hospital discharge dataset • Administrative • Sensitive to hospital bed availability and changes in service • Reasonable for severe, life-threatening disease
Physician Visit and Emergency Datasets • Administrative • Sensitive to individual physician practices • Diagnostic codes very non-specific • General impression of the health of the community
Notifiable disease registry • Surveillance • All cases are lab confirmed so the pathogen is known (specificity of diagnosis) • Zoonotic • Infectious • Serious under-reporting and bias
Conclusions • Only the Notifiable Disease Registry has enough information on each case to be useful specifically in the surveillance of zoonotic, enteric disease in Alberta • However results obtained from analyses of this data need to be interpreted with caution