Glycated haemoglobin trajectories and one-year risk of potentially avoidable hospitalisations among adult patients with type 2 diabetes from specialist outpatient clinics of a tertiary hospital: A cohort study

•Little is known about the association between longitudinal HbA1c trajectories and the risk of potentially avoidable hospitalisations in patients with diabetes seeking care at specialist outpatient clinics.•Most study participants had stably low HbA1c trajectory, followed by moderate-stable trajectory, while approximately 7 in 100 and 6 in 100 patients had high-decrease and high-persistent trajectories, respectively.•The high-persistent trajectory was associated with the greatest risks for overall, diabetes, chronic, acute composite of potentially avoidable hospitalisations and all-cause hospitalisations, among the four trajectories.•Determining longitudinal HbA1c trajectories could help to identify the individuals who are at high-risk for PAH for targeted and intensive management to improve care and reduce hospitalisations.