Antibiotic therapy is associated with adverse drug events among older adults with advanced cancer: A cohort study

Older adults with advanced cancer are exposed to antibiotics but estimates of adverse drug events associated with antibiotic therapy are lacking.

Evaluate the association of antibiotic therapy with adverse drug events in older adults with advanced cancer.

Cohort study where the exposure was the ratio of days of therapy of an oral or intravenous antibiotic per patient-day and the outcome was an adverse drug event, defined as cardiotoxicity, hepatotoxicity, nephrotoxicity, Clostridioides difficile infection, or new detection of a multidrug-resistant organism.

Patients aged ⩾65 years with solid tumors from a tertiary care center who received palliative chemotherapy (n = 914).

Mean age was 75 ± 6.6 years, and 52% were female. Common tumors were lung (31%, n = 284) and gastrointestinal (26%, n = 234). Mean time from first course of palliative chemotherapy to index admission was 128 days. Five-hundred thirty (58%) patients were exposed to antibiotics during the index admission; of these, 27% (n = 143) met standardized criteria for infection. Patients were commonly exposed to cephalosporins (33%, n = 298) and vancomycin (30%, n = 276). Among patients exposed to antibiotics, 35% (n = 183/530) developed an adverse drug event. In multivariable testing, antibiotic therapy was associated with development of an adverse drug event (>0 to <1 vs 0 days of therapy/patient-day: adjusted odds ratio [aOR] = 1.9; 95% confidence interval [CI], 1.2-2.8; ⩾1 vs 0 days of therapy/patient-day: aOR = 2.1, 95% CI, 1.4-3.0).

Antibiotic therapy was independently associated with adverse drug events in hospitalized older adults with advanced cancer. These findings may inform antibiotic decision-making among palliative care providers.