A retrospective study of the impact of comorbidity, polypharmacy and demographic factors on patient inclusion and healthcare delivery in phase I oncology trials.

Background: Phase I trials include patients with metastatic cancer and complex health conditions. Understanding baseline comorbidity and demographic features is critical to improving trial design.

Methods: We used electronic patient records to study the association of comorbidity, polypharmacy, and demographic factors on trial recruitment, time on trial, and health service utilisation.

Results: A cohort of 1671 patients was considered for allocation to a phase I study, of whom 518 patients were recruited to a phase I study and 1153 patients were not. A multivariable analysis revealed polypharmacy was associated with lower recruitment to phase I trials with an odds ratio of 0.95 (95% CI: [0.92, 0.99], p = 0.01), and a greater number of emergency admissions with a risk ratio of 1.1 (95% CI: [1.03, 1.17], p = 0.01). Interestingly, comorbidity was not associated with lower recruitment but was associated with a lower time on trial with a hazard ratio of 0.75 (95% CI: [0.62, 0.90], p ≤ 0.001). Demographic factors, including ethnicity, distance of residence from the hospital, and index of multiple deprivation, did not significantly influence these parameters.

Conclusion: Polypharmacy and comorbidity should be considered both in the design of phase I oncology trials and in planning for healthcare utilisation during these trials.