Social capital, neighborhood disadvantage and potentially preventable emergency department visits in metropolitan Baltimore

Purpose:  This study aimed to: 1) describe variation in neighborhood-level social determinants of health (e.g., poverty, diversity); 2) measure geographic variance in potentially preventable emergency department (ED) visit (PPV) rates explained by these determinants; and 3) examine whether neighborhood-level social capital can mediate the impact of living in a disadvantaged neighborhood on PPV rates.

Significance:  Care delivered in EDs is more expensive than out-patient primary care, but at least one in ten U.S. ED visits and about a third of Maryland ED visits are potentially preventable. Geographic variation in PPV rates reflects differences in primary care access and social determinants of health-seeking behavior, with higher rates noted in poor communities. Health inequities and primary care barriers are implicated in these higher rates.

Design:  Social disorganization mediated by social capital theory guided this cross-sectional, ecologic analysis of PPV rate variation in 130 zip code tabulation areas of the Baltimore metropolitan statistical area. This secondary data analysis used Poisson and geographically weighted regression to analyze aggregated data from three public sources.

Results: Significant predictors of PPV rate variance included percentage of people with income less than twice the poverty level, percentage of households receiving public assistance, and female-headed households. Primary care physicians per capita and percent uninsured were not significant predictors. Social capital was a significant partial mediator of all potential predictors reviewed. Factor analysis revealed two components of social capital; social cohesion/trust, but not collective action, remained a significant mediator.

Discussion:  Communities with high social capital may offer health-protective benefits to residents, even mediating the negative impacts of living in a disadvantaged neighborhood.  Reducing PPVs will require consideration of population-level health-seeking behaviors and promotion of neighborhood-level social capital, particularly for single mothers.