Adverse effects associated with long-term use of anticholinergics amongst older adults with intellectual disability: a longitudinal cohort study
Authors: Al Shuhaimi L , Henman M C , McCallion P , McCarron M , O’Dwyer M 
Published: April 2024

Abstract

Introduction
Intellectual disability defined as “a condition characterized by significant limitation in both intellectual functioning and adaptive behaviour that originates before the age of 22”.[1] Older adults with intellectual disability are exposed to high anticholinergic burden, due to the high prevalence of neurological and mental health diseases compared to the general older adult population. The long-term use of anticholinergics is associated with adverse effects such as decline in physical function, cognitive function and higher risk of dementia and Alzheimer disease in the general population. However, a recent scoping review found that there are no longitudinal studies examining adverse effects associated with long-term use of anticholinergics amongst older adults with intellectual disability.[2]

Aim
To examine adverse effects associated with long-term use of medication with anticholinergic activity among older adults with intellectual disability.

Methods
This study examined older adults with intellectual disability aged 40 or over, who participated in wave 1 (2010-11) (W1) and wave 4 (2019-20) (W4) in the Intellectual Disability Supplement to the Irish Longitudinal Study on Aging (IDS-TILDA). Anticholinergic burden was quantified using the Anticholinergic Cognitive Burden (ACB) Scale. Participants were categorised into three groups based on their total ACB score: no exposure (ACB = 0), mild exposure (ACB 1-4) and high exposure (ACB = 5+). Logistic regression used to examine adverse effects reported at W4 associated with ACB score captured at W1. Reported anticholinergic adverse effects were constipation, falls, edentulous, Barthel Index for activity of daily livings, mental health conditions and dementia/Alzheimer’s. The logistic regression model was adjusted for age, gender, level of intellectual disability, residence, epilepsy, and polypharmacy excluding anticholinergic medications.

Results
506 people with intellectual disability participated and 487 (96.24%) provided medication data at both waves. At W1, 30% had no exposure (ACB=0), 40% had mild exposure (ACB = 1-4) and 30% had high ACB score (ACB = 5+). At W4, there was an increase by 5% of those with mild ACB and a reduction of 1.5% and 3.5% in those with no exposure and high ACB exposure respectively. Participants with high ACB score at W1, were significantly associated with falls (OR = 1.97, 95% CI 1.20-3.54), reporting mental conditions (OR = 14.78, 95% CI 7.84 - 27.86) and dementia, Alzheimer’s or taking anti-dementia drugs (N06D) (OR = 0.21, 95% Cl 0.07 - 0.67) at W4, compared to those with no anticholinergic exposure.

Conclusion
The long-term use of anticholinergics was associated with physical and mental adverse effects, and therefore the possibility of anticholinergic deprescribing should be explored and examined to enhance appropriate medicine use among older adults with intellectual disability. This is the first study examined the impact of long-term anticholinergic use among this population. However, further anticholinergic adverse effects should be addressed in future such as decline in cognitive function and frailty.

References
1. American Association on Intellectual and Developmental Disabilities. Defining Criteria for Intellectual Disability: American Association on Intellectual and Developmental Disabilities; 2023 [Available from: https://www.aaidd.org/intellectual-disability/definition
2. Al Shuhaimi L, Henman M, McCallion P et al. The adverse effects of long-term exposure to anticholinergics among people with intellectual disabilities: a scoping review [version 1; peer review: 2 approved]. HRB Open Research. 2022;5(63).