Length of Stay in Emergency Department by ICD-10 Specific and Non-Specific Diagnoses: A Single-Centre Retrospective Study.

The definition of non-specific presentation at a hospital emergency department (ED) has not yet been formally established. The purpose of this study was to assess the relationships between primary ED diagnoses identified by ICD-10 codes and ED length of stay (LOS). Over the course of three years, we examined 134,675 visits at a tertiary hospital. LOS was examined in groups with specific (internal, surgical, neurological, and traumatic diseases) and non-specific diagnoses. Our secondary objective was to measure LOS by age, day of the week, time of day, and season. The median LOS was 182 min (interquartile range: 99-264 min). LOS was 99 min in the traumatic group, while it was 132 min in the surgical group, 141 min in the non-specific group, 228 min in the internal medicine group, and 237 min in the neurological group. Other determinants of LOS were age, revisits, day of the week, and time of arrival-but not a season of the year. In the non-specific group (21% of all diagnoses), the percentage of hospitalizations was higher than in the specific groups. Our results suggest that in clinical practice, the non-specific group should be redefined to also encompass diagnoses from ICD-10 Chapter XXI (block Z00-Z99).