Drug burden index of people ageing with intellectual disability and cognitive complaints attending a specialist memory service.

Background: Medications with sedative or anticholinergic properties should be prescribed with caution in those with cognitive complaints. This is particularly relevant in people ageing with an intellectual disability (ID). Higher drug burden index (DBI) scores are associated with increased frailty and falls and reduced quality of life in older people and increased risk of adverse effects (daytime somnolence, constipation) in those with ID. While previous studies have shown that the ID population has higher rates of drug burden and a higher propensity to be prescribed an antipsychotic than the general population, the degree of burden has not been assessed specifically in those with ID and cognitive complaints.

Methods: We assessed drug burden in a cohort of sequential referrals to a national memory service for people with ID. All patients were referred for assessment of cognitive complaints (self-reported or caregiver-reported problems with memory or cognition). DBI was calculated individually for each participant, and the impact of aetiology of ID, level of ID, age, psychiatric/neurological comorbidities and diagnostic outcome on DBI scores was assessed.

Results: The study population was 58.6% female with a median age of 55 years and aetiology of ID was Down syndrome (DS) in 71.3%. Consensus diagnosis was Alzheimer's dementia in 40.2%, mild cognitive impairment in 29.9% and cognitively unimpaired from baseline in 25.3%. Medication use was high with 95.4% taking medications, with a median number of medications of 4 (interquartile range 4) and a rate of polypharmacy (≥5 medications) of 51.7%. Overall, 65.5% were exposed to sedative or anticholinergic medications with 39.1% exposed to a clinically significant DBI score >1. Those with psychiatric comorbidities, non-DS aetiology or epilepsy were significantly more likely to have a DBI score >1.

Conclusions: People with ID and incipient cognitive complaints have a high level of drug burden, which concerningly exceeds that of the general population.