158Does The Anticholinergic Burden Of Drugs Predict Outcomes In People With Parkinson's Disease With A History Of A Fall?

Abstract

Introduction: Anticholinergics are widely used in Parkinson's disease (PD) patients, for indications such as tremor and urinary incontinence. Cholinergic loss contributes to cognitive dysfunction, gait disturbance and falls and therefore drugs with anticholinergic properties may exacerbate these features. We sought to determine whether the anticholinergic burden of drugs predicted outcomes in PD. Methods: One hundred and thirty participants were recruited to a phase II trial of rivastigmine to stabilise gait in PD (The ReSPonD trial). At baseline and 8-month follow-up, all participants underwent the following assessments: comprehensive drug history from which Levodopa Equivalence (LED) and Anticholinergic Cognitive Burden (ACB) Scale were calculated; cognition measured with the Montreal Cognitive Assessment (MoCA); disease severity with the MDS-UPDRS; functional mobility (gait speed) and gait (step time) variability were measured with a tri-axial accelerometer (McRoberts). Falls were ascertained prospectively during the 8-month period. Results: Approximately half (52% (n = 67/130)) of participants were taking medication with anticholinergic activity at baseline. At baseline, younger age, greater disease severity, and higher LED were strongly associated with having a higher anticholinergic burden. Anticholinergic burden at baseline did not predict cognition, gait speed or variability, MDS-UPDRS or falls at follow-up. Linear regression analysis, adjusted for age, baseline LED, treatment arm and MDS-UPDRS, showed that, at follow-up, for every point increase in ACB score, LED was reduced by 34 mg (95%CI -63 mg to -4 mg, p = 0.03). Conclusion: The results suggest that higher anticholinergic burden score is associated, longitudinally, with lower LED. This may reflect the inability of patients with high anticholinergic burden to tolerate higher doses of dopaminergic drugs. Lack of prediction of other factors may have resulted from a type II error or insensitivity of measurement instruments. Studies with larger numbers of patients, over a longer period, could further explore the association between anticholinergic burden, cognitive decline, falls and disease severity.