Drug Burden Index in older palliative care inpatients: a medication safety retrospective cohort study

OBJECTIVES: Polypharmacy can increase symptom burden and reduce quality of life in palliative care patients. The Drug Burden Index (DBI) measures patients' exposure to anticholinergic and sedative medications, but has not previously been validated in the palliative care population. This study aimed to quantify the DBI in an older palliative care inpatient population, and examine its associated functional, symptom and delirium outcomes. METHODS: A retrospective cohort study was conducted on patients aged 65 years and older admitted to a specialist palliative care unit in Sydney, Australia, over a 3-month period. Demographic data, admission characteristics, medication exposure and clinical scores were collected via medical record review. Patients' DBI on admission and at 24 hours post-admission were calculated based on regular and pro re nata (PRN) medications. RESULTS: 79 patients were enrolled, who used a mean of 6.3 (SD 4.4) regular medications on admission, with a corresponding mean DBI of 0.69 (SD 0.55). At 24 hours post-admission, the DBI increased in 37% of patients and the resultant mean DBI was 0.82 (SD 0.58), which increased to 1.01 (SD 0.64) when administered PRN medications were included. There was no significant correlation on univariate analysis between patients' DBI on admission and their functional, symptom or delirium scores or length of hospital stay. CONCLUSIONS: Older palliative care patients are frequently exposed to anticholinergic and sedative medications. The DBI is a practical tool which can prompt medication review and inform safe, individualised prescribing in the palliative care setting in line with patients' goals of care.