Diagnostic errors reported in primary healthcare and emergency departments: A retrospective and descriptive cohort study of 4830 reported cases of preventable harm in Sweden.

Background: Diagnostic errors are a major patient safety concern in primary healthcare and emergency care. These settings involve a high degree of uncertainty regarding patients' diagnoses and appear to be those most prone to diagnostic errors. Diagnostic errors comprise missed, delayed, or incorrect diagnoses preventing the patient from receiving correct and timely treatment. Data regarding which diagnoses are affected in these settings are scarce. Objectives: To understand the distribution of diagnoses among reported diagnostic errors in primary health and emergency care as a step towards creating countermeasures for safer care. Methods: A retrospective and descriptive cohort study investigating reported diagnostic errors. A nationwide cohort was collected from two databases. The study was performed in Sweden from 1 January 2011 until 31 December 2016. The setting was primary healthcare and emergency departments. Results: In total, 4830 cases of preventable harm were identified. Of these, 2208 (46%) were due to diagnostic errors. Diagnoses affected in primary care were cancer (37% and 23%, respectively, in the two databases; mostly colon and skin), fractures (mostly hand), heart disease (mostly myocardial infarction), and rupture of tendons (mostly Achilles). Of the diagnostic errors in the emergency department, fractures constituted 24% (mostly hand and wrist, 29%). Rupture/injury of muscle/tendon constituted 19% (mostly finger tendons, rotator cuff tendons, and Achilles tendon). Conclusion: Our findings show that the most frequently missed diagnoses among reported harm were cancers in primary care and fractures in the emergency departments.