Risk of stroke associated with risperidone in dementia with and without comorbid cardiovascular disease: population-based matched cohort study.

BACKGROUND Agitation and aggression occur in up to half of people living with dementia over the course of the disease. Although non-pharmacological interventions are used as first-line treatment strategies, antipsychotics may be indicated in severe cases. A major adverse effect of antipsychotics in dementia is stroke; the mechanism of action of atypical antipsychotic risperidone has been linked to cardiovascular disease (CVD) biological pathways in preclinical studies. AIMS To evaluate the risk of stroke associated with risperidone across different patient subgroups defined by stroke and CVD history. METHOD Anonymised primary care data from the UK-based Clinical Practice Research Datalink were used to identify individuals diagnosed with dementia after the age of 65 years between 2004 and 2023. Risk of stroke over 1 year was compared between individuals initiating risperidone and propensity-score-matched controls across subgroups with and without history of stroke and any CVD. RESULTS In the overall cohort (28 403 risperidone users and 136 324 mtatched controls), risperidone was associated with increased risk of stroke (adjusted hazard ratio: 1.28; 95% CI: 1.20-1.37). In the risperidone user group, the incidence rate of stroke was substantially higher in those with a prior history of stroke (incidence rate: 222 per 1000 person-years) and CVD (incidence rate: 94.1 per 1000 person-years) than in the overall cohort (incidence rate: 53.3 per 1000 person-years). Relative risks related to risperidone were similar across all CVD and stroke subgroup comparisons (hazard ratios between 1.23 and 1.44). CONCLUSIONS People with dementia with a prior history of CVD are at a significant increased risk of stroke, and risperidone further exacerbates this risk. Moreover, risperidone increases risk of stroke in patients without a prior history of CVD. This quantification of stroke risk across subgroups with and without history of CVD may help with communication of risk and aid more judicious prescribing.