Improving the identification of Postoperative Wound Dehiscence missed by the Patient Safety Indicator algorithm

BackgroundThe Patient Safety Indicator (PSI) Postoperative Wound Dehiscence (PWD) is an administrative data-based algorithm that flags cases using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code 54.61 (abdominal wall disruption reclosure). We examined how often PWD missed events and explored ways to improve event identification.MethodsWe selected 125 high-risk unflagged cases based on predicted probability and the presence of clinically relevant codes. We determined the false-negative proportion and associated reasons through chart review and calculated likelihood ratios of associated codes.ResultsThirty-two percent of cases were false negatives, 60% of which lacked any abdominal wall repair codes. All individual codes had low likelihood ratios; the combination of diagnosis code 998.3x (operative wound disruption) and particular abdominal wall repair procedure codes occurred exclusively in false-negative cases (representing 24% of false-negative cases).ConclusionsAmong high-risk cases, the PWD algorithm frequently missed events. Coder training to clarify assignment of abdominal wall repair codes, plus adding specific code combinations to the algorithm, would improve event identification.