Broad-Spectrum Antibiotic Use at the End of Life in Patients With Advanced Cancer.

Importance: Patients with advanced cancer frequently receive broad-spectrum antibiotics, but changing use patterns across the end-of-life trajectory remain poorly understood. Objective: To describe the patterns of broad-spectrum antibiotic use across defined end-of-life intervals in patients with advanced cancer. Design, Setting, and Participants: This nationwide, population-based, retrospective cohort study used data from the South Korean National Health Insurance Service database to examine broad-spectrum antibiotic use among patients with advanced cancer who died between July 1, 2002, and December 31, 2021. Data extraction and analysis were conducted between September 2023 and August 2024. Exposure: A diagnosis of lung cancer, liver cancer, stomach cancer, colorectal cancer, pancreatic cancer, prostate cancer, gallbladder and biliary tract cancer, breast cancer, non-Hodgkin lymphoma, leukemia, or multiple myeloma. Main Outcomes and Measures: The use of broad-spectrum antibiotics (ie, antipseudomonal β-lactams, carbapenems, or glycopeptides) was evaluated using 2 metrics according to end-of-life trajectory: (1) prescription proportion (percentage of patients receiving antibiotics) and (2) consumption amount (days of therapy per 1000 patient-days). The end-of-life trajectory was divided into 5 intervals: T1 (6 months to 3 months before death), T2 (3 months to 1 month before death), T3 (1 month to 2 weeks before death), T4 (2 weeks to 1 week before death), and T5 (final week before death). Logistic regression was performed to calculate odds ratios and 95% CIs for antibiotic prescription proportion without adjustment for multiple comparisons, and Poisson regression was used to calculate adjusted relative risks. Results: Among the 515 366 decedents included, the mean (SD) age was 68.8 (11.7) years, and 347 327 (67.4%) were male. A total of 483 405 patients (93.8%) had solid tumors, with lung cancer (122 142 patients [23.7%]) being the most common type. Overall, 288 151 patients (55.9%) received broad-spectrum antibiotics during the last 6 months of life. The proportion of patients receiving broad-spectrum antibiotics peaked during T2, with 144 920 (28.1%) receiving at least 1 dose, and declined to 68 564 (13.3%) during T5. In contrast, total consumption peaked during T3, reaching 190.0 days of therapy per 1000 patient-days. These patterns were consistent across antibiotic classes and cancer types. During the last week of life, patients with leukemia had the highest exposure to broad-spectrum antibiotics compared with those with lung cancer, both for prescription proportions (crude odds ratio, 1.50; 95% CI, 1.43-1.58) and total consumption (adjusted relative risk, 1.21; 95% CI, 1.19-1.23). Conclusions and Relevance: In this cohort study of patients with advanced cancer, broad-spectrum antibiotic use increased from 3 months to 2 weeks before death, suggesting that this may be a key period for optimizing use and aligning care with patient goals.