Association of the Drug Burden Index (DBI) exposure with outcomes: A systematic review.

Background: The Drug Burden Index (DBI) measures an individual's total exposure to anticholinergic and sedative medications. This systematic review aimed to investigate the association of the DBI with clinical and prescribing outcomes in observational pharmaco-epidemiological studies, and the effect of DBI exposure on functional outcomes in pre-clinical models.

Methods: A systematic search of nine electronic databases, citation indexes and gray literature was performed (April 1, 2007-December 31, 2022). Studies that reported primary data on the association of the DBI with clinical or prescribing outcomes conducted in any setting in humans aged ≥18 years or animals were included. Quality assessment was performed using the Joanna Briggs Institute critical appraisal tools and the Systematic Review Centre for Laboratory animal Experimentation risk of bias tool.

Results: Of 2382 studies screened, 70 met the inclusion criteria (65 in humans, five in animals). In humans, outcomes reported included function (n = 56), cognition (n = 20), falls (n = 14), frailty (n = 7), mortality (n = 9), quality of life (n = 8), hospitalization (n = 7), length of stay (n = 5), readmission (n = 1), other clinical outcomes (n = 15) and prescribing outcomes (n = 2). A higher DBI was significantly associated with increased falls (11/14, 71%), poorer function (31/56, 55%), and cognition (11/20, 55%) related outcomes. Narrative synthesis was used due to significant heterogeneity in the study population, setting, study type, definition of DBI, and outcome measures. Results could not be pooled due to heterogeneity. In animals, outcomes reported included function (n = 18), frailty (n = 2), and mortality (n = 1). In pre-clinical studies, a higher DBI caused poorer function and frailty.

Conclusions: A higher DBI may be associated with an increased risk of falls and decreased function and cognition. Higher DBI was inconsistently associated with increased mortality, length of stay, frailty, hospitalization or reduced quality of life. Human observational findings with respect to functional outcomes are supported by preclinical interventional studies. The DBI may be used as a tool to identify older adults at higher risk of harm.