Associations between access to healthcare, environmental quality, and end-stage renal disease survival time: Proportional-hazards models of over 1,000,000 people over 14 years
Citation:
Kosnik, M., D. Reif, D. Lobdell, T. Astell-Burt, X. Feng, J. Hader, AND J. Hoppin. Associations between access to healthcare, environmental quality, and end-stage renal disease survival time: Proportional-hazards models of over 1,000,000 people over 14 years. PLOS ONE . Public Library of Science, San Francisco, CA, 14(3):e0214094, (2019). https://doi.org/10.1371/journal.pone.0214094
Impact/Purpose:
This study addresses research questions under Sustainable and Healthy Communities (Project 2.64 Indicators, Indices & Report on the Environment and Project 2.62 Community Public Health & Well-Being). National Health Environmental Effects Research Laboratory in the Environmental Public Health Division, Epidemiology Branch is currently engaged in research aimed at developing a measure that estimates overall environmental quality at the county level across the U.S. spanning the years 2000 – 2005 called the Environmental Quality Index (EQI). This work is being conducted for the purpose of learning more about how various environmental factors contribute in concert to health disparities in low-income, underrepresented minority and vulnerable populations, and to better estimate the total environmental and social context to which humans are exposed. To investigate the role of the broader environment on end-stage renal disease survival time, this study evaluated both average distance to the nearest hospital by county (as a surrogate for access to healthcare) and the EQI at the county level across the US.
Description:
Prevalence of end-stage renal disease (ESRD) in the US increased by 74% from 2000 to 2013, with a 5-year survival of 42%. To investigate the role of the broader environment on ESRD survival time, we evaluated both average distance to the nearest hospital by county (as a surrogate for access to healthcare) and the Environmental Quality Index (EQI), an aggregate measure of ambient environmental quality composed of five domains (air, water, land, built, and sociodemographic), at the county level across the US. Associations between average hospital distance, EQI, and survival time for 1,092,281 people diagnosed with ESRD between 2000 and 2013 (18+ years of age and without changes in county residence) from the US Renal Data System were evaluated using proportional-hazards models adjusting for gender, race, age at first ESRD service date, BMI, alcohol and tobacco use post-ESRD diagnosis, and rurality. The models compared the average distance to the nearest hospital (20 miles) and overall EQI percentiles [0-5), [5-20), [20-40), [40-60), [60-80), [80-95), and [95-100], where lower percentiles are interpreted as better EQI. In the full, non-stratified model with both distance and EQI included, there was an increased survival for patients over 20 miles from a hospital compared to those under 10 miles from a hospital (hazard ratio=1.14, 95% confidence interval=1.12-1.15) and no consistent direction of association across EQI strata. In the full model stratified by average hospital distance, those living under 10 miles from a hospital had increased survival in the worst EQI strata (median survival 3.0, interquartile range (IQR)=0.9-6.5 years vs. 3.5, IQR=1.1-7.6 years for best vs. worst EQI, respectively), however for people living over 20 miles from a hospital, median survival was higher in the best (4.2, IQR=1.5-8.5 years) vs worst (3.4, IQR=1.2-7.1 years) EQI. This association held across different rural/urban categories and age groups. These results demonstrate the importance of considering multiple factors when studying ESRD survival and future efforts should consider incorporating additional components of the broader environment.
URLs/Downloads:
DOI: Associations between access to healthcare, environmental quality, and end-stage renal disease survival time: Proportional-hazards models of over 1,000,000 people over 14 years