Polypharmacy and anticholinergic burden scales in older adults: a cross-sectional study among psychiatric outpatients in a tertiary care hospital

Abstract

Introduction: Mental disorders are prevalent among older adults, often leading to the use of multiple medications, many with anticholinergic properties. Polypharmacy, common in this population, is a major contributor to anticholinergic burden, which is linked to cognitive and physical decline. This study investigates the relationship between polypharmacy and anticholinergic burden across seven anticholinergic burden scales in elderly patients attending the psychiatric outpatient.

Methods: Study was conducted at a psychiatry outpatient clinic at All India Institute of Medical Sciences, Rishikesh, India, from December 2021 to March 2023. Elderly patients (aged ≥ 60 years) who were on at least one psychotropic medication and had a primary working diagnosis of psychiatric illness were included. All psychotropic medications, including antidepressants, antipsychotics, mood stabilizers, and hypnotics, were evaluated. Anticholinergic burden scales were calculated by the respective tools. Univariate analysis was adopted to determine the factors that may affect polypharmacy.

Results: Study included 1165 elderly patients aged ≥ 60 years. The prevalence of polypharmacy was 20.43% (n = 238). Clonazepam (n = 364, 17.28%), escitalopram (n = 197, 9.35%), metformin (n = 165, 7.83%), sertraline (n = 141, 6.69%), mirtazapine (n = 129, 6.12%), and lorazepam (n = 110, 5.22%) were among the most frequently prescribed anticholinergic drugs. Univariate analysis demonstrated that all anticholinergic risk assessment scales were closely correlated with polypharmacy, with the strongest association observed for the Anticholinergic Load Scale (ALS) (Odds Ratio = 4.3; p < 0.001). Polypharmacy was also positively associated with adverse drug reactions (Odds Ratio = 1.81; 95% Confidence Interval = 1.27-2.56).

Conclusion: The anticholinergic burden in this cohort of elderly psychiatry patients was high, with 95.1% (n = 1108) experiencing a significant burden. Adverse drug events and anticholinergic burden scales were positively associated with polypharmacy, with a stronger correlation between polypharmacy and ALS scores than with other anticholinergic burden scales in older adults.

Keywords: Anticholinergic burden; Elderly; Polypharmacy; Psychotropics.

Fig. 1

STROBE flow chart. STROBE, Strengthening the Reporting of Observational Studies in Epidemiology. The STROBE flow chart details the study selection process for patients visiting the psychiatric outpatient. Patients visiting the psychiatric outpatient were assessed for eligibility to be included in the study. Informed consent was obtained. A total of 1165 patients were recruited and analysed at the end of the study duration. Abbreviation: ICD-10-CM 10th revision of the International Statistical Classification of Diseases and Related Health Problems

Fig. 2

Prevalence of polypharmacy across different age groups stratified by gender (n = 1165) Prevalence of polypharmacy across different age groups stratified by gender. The bar chart represents the percentage of individuals using polypharmacy (defined as the concurrent use of five or more medications) across various age groups: 60–64, 65–69, 70–74, and 75 + years. The chart compares total prevalence (solid bars) with male (dashed bars) and female (dotted bars) subgroups. The highest prevalence of polypharmacy is observed in the 75 + age group, particularly among females. In all age groups, females tend to exhibit a higher prevalence of polypharmacy than males. The overall trend shows increasing polypharmacy with advancing age

Fig. 3

Frequency and Maximum Scores for Anticholinergic Drugs across Seven Anticholinergic Burden Scales. Frequency and Maximum Scores for Anticholinergic Drugs across Seven Anticholinergic Burden Scales. This figure presents the anticholinergic burden scores assigned to various drugs based on seven different scales, which are highlighted using yellow and pink shading. Yellow represents lower anticholinergic burden scores (1 or 2), while pink indicates higher anticholinergic burden scores (3). Each row corresponds to a specific drug, and the columns list the anticholinergic scores from each scale. The drugs are organized to display their variability in scoring across scales, highlighting differences in how each scale evaluates anticholinergic burden. Drugs with a score of 3 (high anticholinergic effect) on multiple scales are shaded in pink, indicating stronger anticholinergic potential according to those scales. This visualization helps to contrast the scoring systems and identify discrepancies in drug classification across the scales. Abbreviations: ACB Anticholinergic Cognitive Burden, ARS: Anticholinergic Risk Scale, ADS Anticholinergic Drug Scale, ALS: Anticholinergic Load Scale, CrAS Clinician-rated Anticholinergic Scale, AEC Anticholinergic Effect on Cognition, CALS CRIDECO Anticholinergic Load Scale

Fig. 4

The odds ratios of polypharmacy according to the anticholinergic burden scales and other variables. Odds Ratios for Polypharmacy vs Various Variables. This plot displays ORs and 95% Cis for different variables influencing polypharmacy in older psychiatric outpatients. Key findings include significant associations with adverse drug reactions (OR = 1.81), presence of antipsychotics (OR = 1.64), and various anticholinergic burden scores. The ALS score shows the strongest association with polypharmacy (OR = 4.30). The x-axis represents odds ratios, indicating the impact strength of each variable on polypharmacy likelihood, with values over 1 indicating increased likelihood. Abbreviations: ACB Anticholinergic Cognitive Burden, ARS: Anticholinergic Risk Scale, ADS Anticholinergic Drug Scale, ALS: Anticholinergic Load Scale, CrAS Clinician-rated Anticholinergic Scale, AEC Anticholinergic Effect on Cognition, CALS CRIDECO Anticholinergic Load Scale