Ten‐Year Outcomes of Anticholinergic Use Among Older Adults With Intellectual Disability: Findings From the Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing (IDS‐TILDA)

Abstract

Background: People with intellectual disability are frequently exposed to medication with anticholinergic activity. In the general population, the long‐term exposure to anticholinergics has been associated with declines in both physical and cognitive function. This study aimed to examine anticholinergic exposure longitudinally in a cohort of older adults with intellectual disability (aged 40 years or over). Method: The study examined individuals with intellectual disability aged 40 and over, who participated at two time points (Waves 1 and 4), 10 years apart, in the Intellectual Disability Supplement to the Irish Longitudinal Study on Ageing (IDS‐TILDA). The Anticholinergic Cognitive Burden (ACB) scale was used to quantify anticholinergic exposure. Logistic regression analysis was employed to examine the adverse outcomes reported at time point 2 in relation to ACB scores at time point 1. Models were adjusted for age, gender, level of intellectual disability, residence, epilepsy and polypharmacy. Results: The study included 487 participants who provided medication data at both time points. Anticholinergic exposure remained consistent over the studied period, with approximately 30% having no exposure, 40% having mild exposure (ACB = 1–4) and 30% having high exposure (ACB = 5+). Antipsychotic medications contributed the most to the total score at both time points (Wave 1 = 35%, Wave 4 = 37%), with other anticholinergics, antiepileptics and antidepressant medications contributing 10%–16% each. Mild and high ACB scores at time point 1 were significantly associated with a higher risk of falls (odds ratio [OR] = 1.86, 95% CI: 1.03–3.38) and mental health conditions (ACB 1–4; OR = 6.60, 95% CI: 3.69–11.77; ACB 5+, OR = 17.38, 95% CI: 8.97–33.61) and lower OR for reporting dementia/Alzheimer's disease (ACB 1–4; OR = 0.39, 95% CI: 0.15–0.97; ACB 5+; OR = 0.21, 95% CI: 0.07–0.64). Conclusion: Older adults with intellectual disability are exposed to high anticholinergic burden at the two time points, 10 years apart. Being exposed to anticholinergics at Wave 1 is significantly associated with a higher risk of falls and reporting mental health conditions at Wave 4. A review of antipsychotic prescribing practice is urgently needed to reduce the anticholinergic exposure and its adverse outcomes among older adults with intellectual disability.