Urban Spatial Accessibility of Primary Care and Hypertension Control and Awareness on Chicago's South Side: A Study From the COMPASS Cohort

Background: Understanding the relationship between hypertension and spatial accessibility of primary care can inform interventions to improve hypertension control and awareness, especially among disadvantaged populations. This study aims to investigate the association between spatial accessibility of primary care and hypertension control and awareness. Methods: Participant data from the COMPASS (Chicago Multiethnic Prevention and Surveillance Study) between 2013 and 2019 were analyzed. All participants were geocoded. Locations of primary care providers in Chicago were obtained from MAPSCorps. A score was generated for spatial accessibility of primary care using an enhanced 2-step floating catchment area method. A higher score indicates greater accessibility. Measured hypertension was defined as systolic blood pressure >= 130 mm Hg or diastolic blood pressure >= 80 mm Hg. Logistic regression was used to estimate odds ratio and 95% CI for hypertension status in relation to accessibility score quartiles. Results: Five thousand ninety-six participants (mean age, 53.4 +/- 10.8) were included. The study population was predominantly non-Hispanic black (84.0%), over 53% reported an annual household income <$15 000, and 37.3% were obese. Measured hypertension prevalence was 78.7% in this population, among which 37.7% were uncontrolled and 41.0% were unaware. A higher accessibility score was associated with lower measured hypertension prevalence. In fully adjusted models, compared with the first (lowest) quartile of accessibility score, the odds ratio strengthened from 0.82 (95% CI, 0.67-1.01) for the second quartile to 0.75 (95% CI, 0.62-0.91) for the third quartile, and further to 0.73 (95% CI, 0.60-0.89) for the fourth (highest) quartile. The increasing trend had a P<0.01. Similar associations were observed for both uncontrolled and unaware hypertensions. When stratified by neighborhood socioeconomic status, a higher accessibility score was associated with lower rates of unaware hypertension in both disadvantaged and nondisadvantaged neighborhoods. Conclusions: Better spatial accessibility of primary care is associated with improved hypertension awareness and control.