Purpose: Medications with anticholinergic and sedative properties are widely used among older adults despite strong evidence of harm. The drug burden index (DBI), a pharmacological screening tool, measures these properties across drug classes, and higher DBI drug exposure (DBI > 1) has been associated with certain physical function-related adverse events. Our aim was to quantify mean daily DBI drug exposure among older adults in the United States (US).
Methods: We screened medications for DBI properties and operationalized the DBI for US Medicare claims. We then conducted a retrospective cohort study of a 20% random, nationwide sample of 4 137 384 fee-for-service Medicare beneficiaries aged 66+ years (134 757 039 person-months) from January 2013 to December 2016. We measured the monthly distribution based on mean daily DBI, categorized as (a) >0 vs 0 (any use) and (b) 0, 0 < DBI ≤ 1, 1 < DBI ≤ 2, and DBI > 2, and examined temporal trends. We described patient-level factors (eg, demographics, healthcare use) associated with high (>2) vs low (0 < DBI≤1) DBI drug exposure.
Results: The distribution of the mean daily DBI, aggregated at the month-level, was: 58.1% DBI = 0, 29.0% 0 < DBI≤1, 9.3% 1 < DBI≤2, and 3.7% DBI > 2. Predictors of high monthly DBI drug exposure (DBI > 2) included certain indicators of increased healthcare use (eg, high number of drug claims), white race, younger age, frailty, and a psychosis diagnosis code.
Conclusions: The predictors of high DBI drug exposure can inform discussions between patients and providers about medication appropriateness and potential de-prescribing. Future Medicare-based studies should assess the association between the DBI and adverse events.
Keywords: aging; cholinergic antagonists; drug burden index; drug utilization; hypnotics and sedatives; inappropriate prescribing; pharmacoepidemiology.
© 2020 John Wiley & Sons Ltd.