Purpose: Diagnostic adverse events (DAEs) are an important error type as they are often considered to be preventable and the consequences are judged to be severe. Therefore, reducing the number and severity of DAE is particularly important. The design of prevention strategies aimed at reducing DAEs can possibly be rationalised by examining how the causes of DAE differ from the causes of other adverse event (AE) types. Therefore, our study focuses on the causes of DAE in comparison to the causes of other AE types.
Method: A three stage retrospective patient record review study of 7926 patient records was conducted. The method used in this study was based on the well-known protocol developed by The Harvard Medical Practice Study in New York in 1984. To determine whether the AE occurred, trained physicians reviewed randomly selected patient records. Subsequently, the causes were assessed using the Eindhoven Classification Model. This classification model defines 4 main causes categories (human, organizational, technical and patient-related factors). The main categories are divided into 20 subcategories based on the model of unsafe acts (Reason 1990) and the SRK-model (Rasmussen 1976). We compared the causes of DAEs with the causes of other AE types.
Result: The main categories human causes and organizational factors occurred more often in DAE than in other AE types (human: 96.3% versus 50,5%, p <0,0001; organizational: 25.0% versus 12.7% p< 0.005). Patient-related factors were more often involved in the occurrence of other AE types (30.0% versus 44.9% p; <0.05). The influence of technical factors was marginal in all AE types. The analysis of the subcategories of the causes showed that especially subcategories involving (transfer of) knowledge occurred more often in DAEs; Knowledge-based (p< 0.00001), coordination (p< 0.0001) and transfer of knowledge (p< 0.01).
Conclusion: The study showed a substantial contribution of human causes to DAE. Besides the human causes, organisational causes, in particular transfer of knowledge, occurred relatively frequent in DAEs. Possible prevention strategies should focus on expanding physicians' general knowledge to reduce the occurrence of knowledge-based mistakes and training of the non-technical skills to improve transfer of knowledge and coordination. However, more research on the development, implementation and effectiveness of interventions is needed.
Candidate for the Lee B. Lusted Student Prize Competition