Impact of a national time target for ED length of stay on patient outcomes.

AIM: The impact of national targets for emergency department (ED) length of stay (LOS) on patient care is unclear. This study aimed to determine the effect of New Zealand's six-hour time target (95% of ED patients discharged or admitted to hospital within six hours) on a range of quality indicators. METHODS: A nationwide observational study from 2006 to 2012 modelled differences in changes over time before and after target introduction in 2009. The observed model estimates in 2012 were compared to those predicted if pre-target trends had continued. Differences are absolute values except for morality, which is presented as a relative change. RESULTS: There were 5,793,767 ED presentations and 2,082,374 elective admissions from 18 out of a possible 20 district health boards included in the study. There were clinically important reductions in hospital LOS (-0.29 days), EDLOS (-1.1 hours), admitted patients EDLOS (-2.9 hours), ED crowding (-26.8%), ED mortality (-57.8%), elective inpatient mortality (-42.2%) and the proportion not waiting for assessment (-2.8%). Small changes were seen in time to assessment in the ED (-3.4 minutes), re-presentation to ED within 48 hours of the index ED discharge (-0.7%), re-presentation to ED within 48 hours from ward discharge (+0.4%) and acute admissions (+3.9%). An increase was observed in re-admission to a ward within 30 days of discharge (1.0%). These changes were all statistically significant (p<0.001). CONCLUSION: Most outcomes we investigated either improved or were unchanged after the introduction of the time target policy in New Zealand. However, attention is required to ensure that reductions in hospital length of stay are not at the expense of subsequent re-admissions.