Development and validation of a poisoning surveillance program with automatic case detection in a tertiary care hospital (SAT-HULP)

Muñoz R, Borobia AM, Quintana M, Martínez-Virto AM, Frías J, Carcas AJ

Objective: The aim was to develop and validate a tool for automatic, systematic

recording of acute poisoning cases attended in the emergency department of our

tertiary care teaching hospital and to analyze the systems performance during the first 7

months of active surveillance.

Methods: The active poisoning surveillance system performs a daily search for cases in

the hospitals computerized case records. The tool uses a truncated keyword list to

systematically find the reasons patients come to the emergency department and the

clinical decisions made. Found cases are entered into a database for recording of type of

poisoning episode, reasons for exposure, causative agent, signs and symptoms, and

treatment. To validate the system we carried out a cross-sectional analysis of a type used

to validate tests; specifically, we calculated appropriate statistics to compare the results

against a gold standard (review of the medical records by a trained human reader).

Results: The validation study was based on a random sample of 1632 patients of the

22 845 attended during the first 4 months the surveillance system was operating (April-

July 2011). The sensitivity of the system was 80.4% (95% CI, 68.5-92.3) and specificity

99.5% (95% CI, 99.1-99.9). Validity was reflected by a rate of correct answers of 98.9%.

The positive and negative predictive values of the system were 83.7% (95% CI, 72.3-

95.0) and 99.4% (95% CI, 98.9-99.8), respectively. The system found a total of 1033

acute poisoning cases; the mean (SD) patient age was 40.9 (17.9) years and 55.2% were

men. Drug abuse accounted for 55.1% of the cases and overdose of medicines for

34.8%. In 52.3% of the cases exposure occurred during various scenarios involving

substance abuse. Suicide attempts were the second most frequent category (32.1%).

Accidental poisoning accounted for 14.3% of the cases.

Conclusions: The poisoning surveillance program developed for our teaching hospitals

toxicology unit is a tool that performs sufficiently well to carry out systematic,

automated searches for the acute poisoning cases attended in an emergency

department. The cumulative incidence rate of acute poisonings detected by the program

was 3%.

Borobia AM, Carcas AJ, Frías J, Martínez Virto AM, Muñoz R, Quintana M