Post Hoc Analyses of a Randomized Controlled Trial for the Effect of Pharmacist Deprescribing Intervention on the Anticholinergic Burden in Frail Community-Dwelling Older Adults

OBJECTIVES: Anticholinergic burden is detrimental to cognitive health. Multiple studies found that a high anticholinergic burden is associated with an increased risk for dementia, changes to the brain structure, function, and cognitive decline. We performed a post hoc analysis of a randomized controlled deprescribing trial. We compared the effect of the intervention on baseline anticholinergic burden across the treatment and control groups and the time of recruitment before and after a lockdown due to the COVID pandemic with subgroup analyses by baseline frailty index. DESIGN: Randomized controlled trial. SETTINGS AND PARTICIPANTS: We analyzed data from a de-prescribing trial of older adults (>65 years) previously conducted in New Zealand that was focused on reducing the Drug Burden Index (DBI). METHODS: We used the anticholinergic cognitive burden (ACB) to quantify the impact of the intervention on reducing the anticholinergic burden. Participants not taking anticholinergics at the start of the trial were excluded. The primary outcome for this subgroup analysis was a change in ACB, measured with the ĝ_Hedges statistic describing the difference in standard deviation units of this change between intervention and control. For this analysis, the trial participants were stratified into low, medium, and high frailty and timing into prior- and post-lockdown (public health measures for COVID-19). RESULTS: Among the 295 participants in this analysis, the median (IQR) age was 79 (74, 85), and 67% were women. For the primary outcome ĝ_Hedges = -0.04 (95% CI -0.26 to 0.19) with a -0.23 mean reduction in ACB in the intervention arm and -0.19 in the control arm. Before lockdown ĝ_Hedges = -0.38 (95% CI -0.84 to 0.04) and post-lockdown ĝ_Hedges = 0.07 (95% CI -0.19 to 0.33). The mean change in ACB for each of the frailty strata was as follows: low frailty (-0.02; 95% CI -0.65 to 0.18); medium frailty (0.05; 95% CI -0.28 to 0.38); high frailty (0.08; 95% CI -0.40 to 0.56). CONCLUSIONS AND IMPLICATIONS: The study did not provide evidence for the effect of pharmacist deprescribing intervention on reducing the anticholinergic burden. However, this post hoc analysis examined the impact of COVID on the effectiveness of the intervention, and further research in this area may be warranted.