Effects of housing value and medical subsidy on treatment and outcomes of breast cancer patients in Singapore: A retrospective cohort study

BACKGROUND: Socioeconomic status (SES) is likely to affect survival in breast cancer patients. Housing value is a reasonable surrogate for SES in Singapore where most residents own their own homes, which could be public (subsidised) or private housing. We evaluated effects of housing value and enhanced medical subsidies on patients’ presentation, treatment choices, compliance and survival in a setting of good access to healthcare. METHODS: A retrospective analysis of breast cancer patients treated in a tertiary hospital cluster from 2000 to 2016 was performed. Individual-level Housing value Index (HI) was derived from each patient's address and then grouped into 3 tiers: HI(high)(minimal subsidy), HI(med)(medium subsidy) and HI(low)(high subsidy). Cox regression was performed to evaluate the associations between overall survival (OS) and cancer-specific survival (CSS) with HI and various factors. FINDINGS: We studied a multiracial cohort of 15,532 Stage 0–IV breast cancer patients. Median age was 53.7 years and median follow-up was 7.7 years. Patients with lower HI presented with more advanced disease and had lower treatment compliance. On multivariable analysis, compared to HI(high) patients, HI(med) patients had decreased OS (HR=1.14, 95% CI 1.05–1.23) and CSS (HR=1.15, 95% CI 1.03–1.27), and HI(low) patients demonstrated reduced OS (HR=1.16, 95% CI 1.01–1.33). Ten-year non-cancer mortality was higher in lower HI-strata. Enhanced medical subsidy approximately halved treatment noncompliance rates but its receipt was not an independent prognostic factor for survival. INTERPRETATION: Despite good healthcare access, lower-HI patients have poorer survival from both cancer and non-cancer causes, possibly due to delayed health-seeking and poorer treatment compliance. Enhanced subsidies may mitigate socioeconomic disadvantages. FUNDING: None.