Adverse effects associated with long-term use of anticholinergics amongst older adults with intellectual disability: a longitudinal cohort study

Abstract

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.