Introduction Asthma exacerbations or ‘attacks’ can vary in severity from mild worsening of symptoms to life-threatening changes that require urgent hospital care. Understanding these exacerbations is crucial to improving treatment and support for patients. Electronic health records (EHR) using anonymised data from people with asthma in primary and secondary care can be used to understand exacerbations and outcomes. However, previous studies found significant heterogeneity in the algorithms used to define asthma exacerbations. Validating definitions of asthma exacerbations in EHR will lead to more robust and comparable evidence in future research.

Methods and analysis Medline and Embase will be searched for the key concepts relating to asthma exacerbations, EHR and validation. All studies that validate exacerbations of asthma in EHR and administrative claims databases published before 30 May 2024 and written in English will be considered. Validated algorithms for asthma exacerbations or attacks must be compared against a reference or gold standard definition, and a measure of validity must be included. Articles will be screened for inclusion by two independent reviewers with any disagreements resolved by consensus or arbitration by a third reviewer. Study details will be extracted, and the risk of bias will be assessed using a QUADAS-2 tailored to this review.