Identifying Predictors and Measuring Variation in Anticholinergic Burden and Sedative Load for Older Adult Care Home Residents: A Retrospective Cohort Study Using Routinely Collected Data.

Purpose: There over 250,000 care home residents in England and they account for a disproportionate number of hospital admissions. Since 2020, structured medication reviews for care home residents have been mandated in primary care contracts. We used a nationally representative cohort of care home residents to identify predictors of anticholinergic burden and sedative load and measure regional variation in prescribing. Patients and Methods: Using primary care data from a third of practices in England we derived four 6-month cohorts of over 40,000 care home residents linked to the national regulator's register of care homes between 01/01/2023 and 31/12/2024. We estimated three-level logistic regression models including resident, postcode district and commissioner (ICB) level factors which predicted high anticholinergic burden and sedative load. We estimated funnel-plots to measure case-mix risk adjusted variation in prescribing at postcode district and commissioner geographical levels. Results: Significant predictors of anticholinergic burden and sedative load included gender, age, frailty, and comorbidity. We demonstrated some case-mix adjusted variation at ICB and postcode district level (anticholinergic burden 2.3-fold ICB and 3.5-fold variation at district level; sedative load 1.7-fold ICB and 2.7-fold variation at District level). Conclusion: This is one of the largest studies of care home residents in England. We have identified factors associated with risk of residents having a high anticholinergic burden or sedative load which could be used to help target personalised interventions.