Comparison of the Poisoning Severity Score and National Poison Data System schemes for the severity assessment of animal poisonings: a pilot study.

CONTEXT: To date, there are no publicly available schemes designed and evaluated specifically for severity assessment of animal poisonings. This poses challenges for the evaluation and comparison of animal poisoning exposure data.

OBJECTIVE: Our objective for this pilot study was to evaluate agreement between raters using the Poisoning Severity Score (PSS) and National Poison Data System (NPDS) medical outcome scheme for severity assessment of canine exposures reported to a multistate poison center (PC) and to identify issues regarding their use for severity assessment of animal poisonings. Agreement between both schemes was also assessed.

METHODS: The first 196 canine exposures reported to a multistate PC between 1 January and 31 August 2016 were selected and initial inquiry data from exposures was scored by four independent raters. Interrater agreement and agreement between the severity systems was calculated using weighted kappa (Κ) (Light's kappa). Reported clinical effects were also described.

RESULTS: Interrater agreement for both the PSS (Κ 0.31; 95% CI 0.19, 0.43) and NPDS schemes (Κ 0.34; 95% CI 0.22, 0.44) was low. Agreement between the schemes was slight (Κ 0.05; 95% CI -0.08, 0.16) for pooled results from all four raters. For the PSS, 71.7% (n = 281) of ratings were minor, 23.0% (n = 90) moderate, and 5.4% (n = 21) severe. For the NPDS, 69.6% (n = 273) of ratings were minor, 27.0% (n = 106) moderate, and 3.3% (n = 13) severe. The top three reported clinical effects included vomiting (n = 86, 29.9%) drowsiness/lethargy (n = 38, 13.2%), and diarrhea (n = 24, 8.3%).

DISCUSSION AND CONCLUSIONS: This study shows considerable variability between raters using either the PSS or NPDS schemes for canine exposures severity assessment. The subjective nature of the schemes, the influence of intra- and interrater variation, and predominance of minor cases on the study findings should be taken into account when interpreting this data. Further evaluation of these schemes is warranted and could help inform their future use for animal poisoning severity assessment.