Pre-ICU medication vulnerability and healthcare-access barriers associated with unplanned intensive care admission among cancer patients: A case-control study

Background Unplanned intensive care unit (ICU) admission is a critical event in the cancer trajectory and is associated with substantial mortality. Medication-related vulnerabilities and healthcare-access barriers may contribute to acute deterioration but remain insufficiently studied together. Objective To identify medication-related and healthcare-access factors independently associated with unplanned ICU admission among adults with cancer. Methods This hospital-based case-control study was conducted at a tertiary oncology centre. Cases were adults with cancer with unplanned ICU admission (n = 150), and controls were adults with cancer admitted to wards or day-care units without ICU requirement (n = 150), frequency-matched by age group, sex, and cancer type. Medication vulnerabilities and healthcare-access barriers were assessed using medical records and structured interviews. Multivariable logistic regression was performed to estimate adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Results Cases had higher prevalence of polypharmacy (64.0% vs 38.7%), clinically significant drug-drug interactions (42.0% vs 20.7%), and medication non-adherence (51.3% vs 29.3%). Financial barriers (58.7% vs 34.7%) and delayed care-seeking (46.0% vs 24.0%) were also more frequent. After adjustment, financial barriers (aOR 2.31, 95% CI 1.34–3.99), drug-drug interactions (2.14, 1.19–3.85), delayed care-seeking (2.08, 1.16–3.72), polypharmacy (2.05, 1.21–3.47), and non-adherence (1.94, 1.12–3.36) remained independently associated with unplanned ICU admission. ICU mortality was 32.0%. Conclusion Medication vulnerabilities and healthcare-access barriers were associated with unplanned ICU admission. These findings identify potentially modifiable areas for further evaluation, but the case-control design does not establish that interventions targeting these factors would directly reduce ICU admissions.