The others: characterizing "other" therapeutic errors reported to a poison center

Background: Therapeutic errors are costly and result in unplanned hospital visits. Recent poison center studies on therapeutic errors have focused on coded data from either the National Poison Data System (NPDS) or individual poison centers. Approximately 21% of therapeutic errors reported to NPDS are coded as "other incorrect dose" (OI) or "other/unknown therapeutic error" (OU). The purpose of this study was to characterize errors coded as OI or OU reported to a single poison center. Methods: Retrospective, single poison center chart review was conducted of therapeutic error exposures with at least one scenario coded as OI or OU seen in or referred to hospitals from 1/1/2000 to 9/30/2017. Cases were reviewed and re-coded to predefined or newly created scenarios. Results: A total of 3413 cases were identified. There were 726 cases assessed as not therapeutic errors and re-coded as either intentional misuse (430), adverse reaction drug (204), or other non-therapeutic errors (82). Of the remaining cases, 1726 cases were re-coded to one of the 16 existing therapeutic error scenarios. After re-coding, there remained 971 coded as OI or OU. Most were due to double, triple, quadruple, or higher than recommended dose (477/971); an additional common error was mistaken strength (81/971). The remaining scenarios occurred in fewer than 50 cases each with greater than 40 different scenarios such that additional coded scenarios would not be feasible. Conclusions: Most cases coded as OI or OU could be recoded as one of the NPDS predefined therapeutic error scenarios or non-error reasons for exposure. Considering the large proportion of double dose cases and the unique errors associated with mistaken strengths of tablets, these scenarios could be appropriate to add as new predefined coding scenarios, which would aid in future research and patient counseling.