Pharmacist Led Intervention to Improve Medication Use in Older In-patients Living With Frailty: the Drug Burden Index

Polypharmacy and inappropriate medication use in older adults is common and associated with a number of harms including adverse drug reactions, falls, hospitalization, reduced quality of life and mortality. There is particular concern about medications with anticholinergic and sedative effects.Older adults may be sensitive to adverse effects of these agents due to changes in pharmacokinetics (increased exposure to the drug) and pharmacodynamics (increased sensitivity to the effects).

Frailty is a condition of cumulative reduction in function of multiple body systems. Frail individuals are vulnerable to external stressors and less able to recover; as such they are at greater risk of medication related harms.

Anticholinergic medications are used for a variety of conditions such as allergic rhinitis, urinary incontinence, and nausea/vomiting. Other medications, including some common anti-depressants also have anticholinergic activity, even when not central to their efficacy. Sedatives may be used short term to treat insomnia and anxiety, however, many medications produce sedation as an unintended side effect. While these medications have therapeutic effects, their use in older adults has been linked to multiple adverse effects manifesting as limitations in physical and cognitive function.Furthermore, there may be reduced or limited benefits of these agents. Taken altogether, in older adults with multi-morbidity and polypharmacy there is a picture of reduced benefit and increased risk associated with use of anticholinergic and sedative medications which may be amplified among frail individuals.

The Drug Burden Index (DBI) is an evidence-based risk assessment tool developed to measure exposure to anticholinergic and sedative medications to determine the effect on physical and cognitive function. DBI score has been associated in several cross-sectional studies with poorer physical function, reduced quality of life, frailty, falls and hospital readmission. Cognition and mortality have been found to be effected by DBI score in some cross-sectional studies, but not others. Longitudinal studies have found increased DBI is independently associated with lower physical function over 5 years, poorer delayed memory performance, increased physician visits and mortality. These results represent 20 different studies, span multiple countries (Australia, Canada, Finland, the Netherlands, New Zealand, UK and US) and provide a substantial argument to reduce DBI score in individuals where possible.

Despite the knowledge of the risks associated with anticholinergic and sedative medications, their use is relatively common with studies showing use of one or more of these agents in approximately 20-80% of older adults. Concerningly, their use may also be more common in frail older adults who are at further risk of harm from medication use. A provincial based point prevalence study conducted within the Nova Scotia Health Authority (NSHA) found an overall prevalence of 35% of benzodiazepine use among patients admitted to acute care.