Emerging burden of post-cancer therapy complications on unplanned hospitalisation and costs among Australian cancer patients: a retrospective cohort study over 14 years.

Cancer treatment using systemic therapy and radiotherapy may cause post-therapy complications, resulting in increased unplanned hospitalisation. The evidence on such complications, their impact on unplanned hospitalisations, and associated costs is scant in Australia. We aimed to estimate the prevalence of post-therapy complications, evaluate their impact on unplanned hospitalisation, length of stay (LOS) and investigate the associated medical costs. A retrospective cohort study was conducted among 8,633 cancer patients (1.03 million emergency hospital admissions) in Victoria, Australia from July 2006 to June 2020, from the Australian healthcare system perspective. Multivariate generalised linear regression models were employed to estimate the adjusted association between post-therapy complications and clinical characteristics with hospital LOS and associated hospitalisation medical costs. Approximately 52% of patients were male with an average patient age of 59.9 years. Annually, post-therapy complications leading to unplanned hospitalisations increased by 7.25%, outpacing the growth in overall hospitalisation admissions, which was 5.66% for overall hospitalisation admissions. A significant proportion of patients (71%) experienced multiple complications, with the most common being anemia (26%), sepsis (15%), nausea and vomiting (14%), and neutropenia (11%). Patients undergoing combined systemic and radiotherapy exhibited higher odds of post-therapy complications (OR = 8.24, 95%CI: 7.48 to 9.08) compared with those who only received systemic therapy. Mean hospital stay among patients who experienced post-therapy complications was 2.23 days per admission (360 days per patient), an extra 1.72 days per admission [95%CI: 1.68 to 1.76; 354 days per patient, 95%CI: 336 to 371 days] longer than patients without complications (0.51 days per admission and 6.48 days per patients). Overall, per-admission medical hospitalisation costs among patients with post-therapy complications were $8,791 higher than for patients who did not experience complications ($11,418 vs. $2,627 per admission, 95%CI: $8,685 to $8,897). Per-patient costs for unplanned hospitalisation due to post-therapy complications were significantly $1.82 million higher among patients than those without complications ($1.86 million vs. $33,599 per patient, 95%CI: $1.71 million to $1.94 million). The cost and hospitalisation stay (in days) varied by the type of therapy and cancer type. The study results indicate that post-therapy complications in cancer patients varied by the type of cancer and increased over the study period, leading to longer unplanned hospital stays and higher hospitalisation medical costs. The results highlight the need for better-customized treatment delivery strategies to address this burden and optimise resources in cancer care.