Drug Burden Index, Physical Function, and Adverse Outcomes in Older Hospitalized Patients

Abstract

The Drug Burden Index (DBI) is associated with poorer physical function in stable, community-dwelling, older people. The authors speculated that a higher DBI is associated with reduced physical function (Barthel Index, primary outcome) and predicts adverse outcomes (length of stay, in-hospital mortality, secondary outcomes) in frail, acutely ill, older hospitalized patients. Clinical and demographic characteristics, Barthel Index, DBI, and full medication exposure were recorded on admission in 362 consecutive patients (84 ± 7 years old) admitted to 2 acute geriatric units between February 1, 2010, and June 30, 2010. A unit increase in DBI was associated with a 29% reduction in the odds of being in a higher Barthel Index quartile than a lower quartile (odds ratio, 0.71; 95% confidence interval, 0.55-0.91; P = .007). The Barthel Index components mostly affected were bathing (P < .001), grooming (P < .001), dressing (P = .001), bladder function (P < .001), transfers (P = .001), mobility (P < .001), and stairs (P < .001). A higher DBI independently predicted length of stay (hazard ratio, 1.23; 95% confidence interval, 1.06-1.42; P = .005) but not in-hospital mortality (hazard ratio, 1.17; 95% confidence interval, 0.72-1.90; P = .52). Higher DBI scores on admission are independently associated with lower scores of the Barthel Index and predict length of stay among older hospitalized patients. The DBI may be useful in the acute setting to improve risk stratification.