It takes a village: Exploring the impact of social determinants on delivery system outcomes for heart failure patients

Background: Local social determinants may act as effect modifiers for the impact of neighborhood material deprivation on patient-level healthcare outcomes. The objective of this study was to understand the mediating effect of local social determinants on neighborhood material deprivation and delivery outcomes in heart failure (HF) patients. Material and methods: A retrospective cohort study was conducted using 4737 HF patients receiving inpatient care (n=6065 encounters) from an integrated healthcare delivery system from 2010 to 2014. Outcomes included post-discharge mortality, readmission risk and length of stay. Deprivation was measured using an area deprivation index by address of residence. Effect modifications measured included urban-rural residency and faith identification using generalized linear regression models. Patient-level data was drawn from the delivery system data warehouse. Results: Faith identification had a significant protective effect on HF patients from deprived areas, lowering 30-day mortality odds by one-third over patients who did not identify with a faith (OR 0.35 95% CI: 0.12-0.98; p=0.05). Significant effects persisted at the 90 and 180-day timeframes. In rural areas, lack of faith identification had a multiplicative effect on 30-day mortality for deprived patients (OR 14.0 95% CI: 1.47-132.7; p=0.02). No significant effects were noted for other healthcare outcomes. Conclusions: The lack of expected association between area deprivation and healthcare outcomes in some communities may be explained by the presence of effect modifiers. Implications: Understanding existing effect modifiers for area deprivation in local communities that delivery systems serve can inform targeted quality improvement. These factors should also be considered when comparing delivery system performance for reimbursement and in population health management.