Exploring the association between surgical out-of-pocket costs and healthcare quality outcomes: a retrospective cohort study

Objectives: Rising out-of-pocket (OOP) costs paid by healthcare consumers can inhibit access to necessary healthcare. Yet, it is unclear if higher OOP payments are associated with better care quality. This study aimed to identify the individual and socio-contextual predictors of OOP costs and to explore the association between OOP costs and quality of care outcomes for 4 surgical procedures. Methods: A retrospective cohort analysis was conducted using data from Medibank Private health insurance members aged ≥18 years who underwent hip replacement, knee replacement, cholecystectomy, and radical prostatectomy during 2015 to 2020 across >300 hospitals in Australia. Healthcare quality outcomes investigated were hospital-acquired complications, unplanned intensive care unit admissions, prolonged length of stay, and readmissions within 28 days. Socio-contextual determinants of OOP costs examined were patient demographics, socioeconomic status, health insurance, and procedure complexity. Generalized linear mixed modeling examined the risk of each outcome, adjusting for covariates and considering patient clustering within surgeons and hospitals. Results: Patients were more likely to pay OOP costs if they were aged 65 to 74 years compared with aged 18 to 44 years for all 4 surgical procedures. No association between OOP payments and the risk of hospital-acquired complications, intensive care unit admission, or hospital readmission was identified. Patients who paid OOP costs were less likely to have a prolonged length of stay for all 4 procedure types. Conclusions: Higher OOP payments were not linked to improved care quality except for shorter hospital stays. Greater transparency on OOP costs is needed to inform consumer decisions.