Prescribing for acute migraine in a rural Australian hospital

Introduction: Migraine is an episodic, debilitating form of headache. Guidelines exist for the management of acute migraine, concluding that opioids should be avoided, unless as a last resort. Australian research shows a poor consistency in ED prescribing patterns with no published rural hospital data. Treatment of acute migraine often involves multiple medications used in succession. The over-prescription of opioids is reported and often accompanied by an underuse of triptans. Previous studies do not differentiate prescriber intervention over time. It is unclear if opioid medications are routinely selected as first-line therapy in rural Australian EDs. The aim of this research is to complete an evaluation of migraine management in a rural Australian ED and compare trends to pre-existing data. 
Methods: A retrospective cohort analysis of clinician-diagnosed migraine patients presenting to a single Australian ED between 1 January 2017 and 31 December 2021. Cases with migraine were defined by a primary G439 ICD10 diagnosis. Patients with alternate diagnoses and those who did not wait were excluded. Cases underwent a non-blinded chart review extracting demographic and clinical data. Diagnoses were not evaluated against the international headache society criteria. ED interventions were recorded as first, second, third, fourth line based on the ordering time by the prescribing doctor. Medications were classified as being compliant or non-complaint with current standards of care. Trends were compared to previous studies. The WACHS HREC reviewed the project and did not raise ethical concern for publication. 
Results: 341 patients were diagnosed with migraine, 72.4% female, median 35 years. 6.5% Ambulance arrival. 76.8% with prior history of migraine. 6.5% admitted, 36.4% underwent blood investigations and 12.0% neuroimaging. 7.6% of patients received opioids as first-line therapy. 44.3% failed self-medication. 21.7% of patients with migraine history trialled opioids prior to presentation. 795 prescriptions were written, 18.1% were non-compliant with guidelines. 70.0% received dopamine and 5-HT3 antagonists, 43.1% NSAIDs, 27.0% serotonin receptor agonists and 27.0% opioids. Statistically significant prescribing difference for aspirin, used in 16.41% of those with a migraine history and 5.1% without (P=0.01).13.8% reported allergies/contraindications to guideline therapies. 
Discussion & Conclusion: Prescribing for acute migraine in Australia is highly variable by context. This single site study has similarities and differences with prior research. Rates of opioid prescribing were lower, possibly due to the known sparing effect of serotonin receptor agonist usage. Similar rates of NSAID and intravenous hydration prescription occurred. Patterns of intervention over time in this rural ED demonstrated strong adherence to guidelines and lowopioid utilisation. Contextual differences proposed to impact prescribing include staff training, medication availability and shorter wait times. Imaging and pathology investigation rates were lower than in prior research and did not change disposition. Future studies across multiple rural hospitals may help understand this topic.