Exploring the reliability and profile of frequent mental health presentations using different methods: An observational study using statewide ambulance data over a 4-year period.

Abstract

A disproportionate number of mental health presentations to emergency services are made by frequent presenters. No current consensus definition of a frequent presenter exists. Using a statewide population-based ambulance database, this study (i) applied previous statistical methods to determine thresholds for frequent presenters, (ii) explored characteristics of the identified frequent presenter groups compared to non-frequent presenters and (iii) assessed the reliability of these methods in predicting continued frequent presenter status over time. Statistical methods utilised in previous studies to identify frequent presenters were applied to all ambulance attendances for mental health symptoms, self-harm and alcohol and other drug issues between 1 January 2017 and 31 December 2020 in Victoria, Australia. Differences in characteristics between identified frequent and non-frequent presenter groups were determined by logistic regression analysis. The consistency of agreement of frequent presenter status over time was assessed using intraclass correlation coefficients. Thresholds for frequent presenters ranged from a mean of 5 to 39 attendances per calendar year, with groups differing in size, service use and characteristics. Compared to non-frequent presenters, frequent presenters had greater odds of being female, presenting with self-harm, experiencing social disadvantage or housing issues, involving police co-attendance and being transported to hospital. All frequent presenter definitions had poor reliability in predicting ongoing frequent presentations over time. A range of methods can define frequent presenters according to thresholds of yearly service use. Reasons for identifying frequent presenters may influence the method chosen. Future studies should explore definitions that capture the dynamic nature of presentations by this group.