RATIONALE AND OBJECTIVE: Persons with end-stage renal disease (ESRD) receiving in-center maintenance hemodialysis may be at high risk for SARS-CoV-2 exposure and severe outcomes with Coronavirus disease 2019 (COVID-19). The objective of this study was to examine the correlation of SARS-CoV-2 positivity rate per capita and COVID-19 associated deaths with number of dialysis stations and demographics of residents within ZIP codes in Cook County, Illinois. STUDY DESIGN: Ecological analysis SETTING AND PARTICIPANTS: Data on SARS-CoV-2 tests and COVID-19 associated deaths during January 21- June 15, 2020 among the 5,232,412 residents living within the 163 ZIP codes in Cook County, Illinois were merged with demographic and income data from U.S. Census Bureau. The total number of positive tests in this population was 84,353 and the total number of deaths was 4007. ASSESSMENTS: Number of dialysis stations and stations per capita within a ZIP code was calculated. The SARS-CoV-2 positive tests per capita was calculated as number of positive tests divided by the ZIP code population. COVID-19 deaths per capita were calculated as the COVID-19 deaths among residents for a given ZIP code divided by the ZIP code population. ANALYTIC APPROACH: Spearman’s rank correlation coefficients were calculated to examine the correlation of SARS-CoV-2 positive tests per capita and COVID-19 deaths per capita with dialysis stations, demographics and household poverty. To account for multiple testing, statistical significance was considered as p<0.005. RESULTS: Among the 163 Cook County ZIP codes, there were 2501 dialysis stations. Positive tests per capita were significantly associated with number of dialysis stations (r = 0.25; 95% CI 0.19, 0.29; P < 0.005) but not with dialysis stations per capita (r=0.02; 95% CI -0.03, 0.08; P = 0.7). Positive tests per capita also correlated significantly with number of households living in poverty (r= 0.57; 95% CI 0.53, 0.6; P < 0.005), and percentage of residents reporting Black race (r = 0.28 p < 0.005, CI = 0.23, 0.33) and Hispanic ethnicity (r = 0.68 p < 0.001, CI: 0.65 — 0.7). COVID-19 deaths per capita correlated significantly with the percentage of residents reporting Black race (r=0.24; 95% CI 0.19, 0.29; P < 0.005) and with percentage of households living in poverty (r=0.34; 95% CI 0.29, 0.38; P < 0.005). The association between the number of COVID-19 deaths per capita and total number of dialysis stations (r=0.20; 95% CI 0.14, 0.25; P = 0.01) did not achieve a priori significance, while the association with dialysis stations per capita (r=0.12; 95% CI 0.07, 0.17; P = 0.01) was not significant. LIMITATIONS: Analysis is at the ZIP code level and not at the person level. CONCLUSION: The number of dialysis stations within a ZIP code correlates with SARS-CoV-2 positivity rate per capita in Cook County, Illinois and this correlation may be driven by population density and the demographics of the residents. These findings highlight the high risk of SARS-CoV-2 exposure for patients with ESRD living in poor urban areas.
Dialysis, COVID-19, Poverty, and Race in Greater Chicago: An Ecological Analysis