Characterising intra-articular corticosteroid injections use in UK primary care: a retrospective cohort study between 2005 and 2020.

Objectives: To characterise the use of intra-articular corticosteroid injections (IACIs) in a large patient cohort with OA in UK primary care from 2005 to 2020. We sought to evaluate IACI practices, identify patterns of administration across different joints, assess regional variation and examine potential demographic factors influencing IACI utilisation for managing OA. Methods: This retrospective cohort study used data from the UK Clinical Practice Research Datalink GOLD, a database of primary care health records. Data from other healthcare settings were not included. Patients ≥20 years of age with a first diagnosis of OA between 2005 and 2019 were included. OA and IACIs were identified through Read and Gemscript codes, respectively. Results: Of 220 125 patients with OA, 11% received at least one IACI. The anatomical location was only specified in 56% of IACI records. The highest proportion of injections occurred in patients with multiple joints diagnosed with OA (19.0%), followed by the shoulder (14.9%) and knee (12.5%). The median time from OA diagnosis to first injection was 0.9 years and was shortest for the shoulder (0.3 years) and longest for the elbow (2.1 years). We observed substantial regional variation, with incidence rates ranging from 1.2 injections per 100 patient-years in the South East Coast to 3.8 in Yorkshire and the Humber. Conclusion: This study observed notable variation in the median time from OA diagnosis to injection, across different joints, with substantial heterogeneity in the incidence of IACIs across UK regions.