Provider-to-population ratios, population health and county-level rurality
Background: Maintaining an adequate health care workforce is one of the most persistent and serious challenges facing rural health care today. Health disparities among rural population are also persistent, with recent county-level analyses demonstrating an inverse relationship between life expectancy and rurality. There has been limited research regarding the relationship between population health and provider-to-population ratios, and few studies address rurality. As the largest group of health care providers, nurses represent a vital force in promoting the health of rural populations; however little previous research has studied this assumption.
Methods: This cross-sectional analysis used existing national data at the county level. Data on 1,929,414 RNs were obtained from the National Council of State Boards of Registered Nursing’s Nursys® database, representing 2017 counties in 33 states. County-level RN-to-population ratios were computed using 2010 U.S. Census data. Primary care physician and dentist-to-population ratios were drawn from the 2012 County Health Rankings database, as were four county-level health measures (premature death rate, self-rated poor or fair health, teen birth rate and mammography screening rate). Four categories of rurality were created based on Rural Urban Continuum Codes. Logistic regression was used to model the county-level health measures using provider-to-population ratio quartiles in each of the rurality categories, adjusted for socio-demographic covariates.
Results: Overall, provider-to-population ratios declined as rurality increased. In fully adjusted models, the highest quartile of each provider-to-population ratio was compared to the lowest quartile. The highest RN-to-population ratio was associated with significantly better health measures in all rurality categories, but the magnitude of these associations generally increased as rurality increased. In the smallest rural counties, the highest RN-to-population quartile was associated with 1508 fewer years of potential life lost (YPLL), 3% lower rates of poor or fair health, 10/1,000 fewer teen births and 5% more mammography screening. For primary care physicians, significant associations were found in medium and small rural counties where the highest ratio was associated with 1411 fewer YPLL, 3% lower rates of poor or fair health, 7/1,000 fewer teen births and 4% more mammography screening. The highest quartile of dentist-to-population ratio was associated with 1104 fewer YPLL, 3% lower rates of poor or fair health, 4/1,000 fewer teen birth and 4% more mammography screening in metropolitan counties.
Implications: The results of this national multifactorial study suggest the number of nurses and other health care professionals per capita matters in promoting healthy communities, particularly in rural areas. These findings strengthen the argument for increasing the ratio of providers-to-population in currently underserved rural areas. Further investigation of the unique impacts of various provider-to-population ratios on population health is warranted, including longitudinal studies tracking changes in ratios and population health measures over time.