A Spatial View of How United States Cesarean Section Rates Changed from 1990 to 2014

Abstract

The overuse of cesarean sections (C-sections) in the United States is a contested issue. The rate of C-section births in 2015 at 32 percent was over double the World Health Organization recommendation of 10 to 15 percent. We employed spatial statistical methods and data visualization techniques to assess the temporal and spatial trends in C-section rates by county across the United States. Although the national rate of C-section remained stable at the beginning and end of this study period, an increase in rates from 1997 to 2009 was reflected simultaneously in national, state, and individual county rates. Local indicators of spatial dependence did not show spatial clustering as being connected to, or driving, the change, yet the visualization methods used here show details on individual county deviance from local temporal trends. By highlighting counties that do not follow the trends of their neighbors, we identify exceptional locations that could help further the study of the determinants of changing C-section rates in the United States. Key Words: cesarean sections, exploratory spatial data analysis, medical geography, spatial statistics.

滥用剖腹产（C-sections）在美国是个饱受争议的议题。2015年剖腹产的比例为百分之三十二, 是全球卫生组织建议的百分之十到十五的两倍。我们运用空间统计方法与数据可视化技术, 评估美国各郡县剖腹产的时空趋势。尽管剖腹产的全国比例, 在本研究期间的开始与结束时维持平稳, 但1997年至2009年比例的上升, 则同时反映在全国、州以及各郡县的比例上。空间依赖的地方指标, 并未展现出与上述改变相关或驱动该改变的空间集群, 但本研究所运用的可视化方法, 却展现出单独郡县异于地方时间趋势的细节。我们通过强调未追随其邻里趋势的郡县, 指认出例外的区位, 并有助于进一步研究美国改变中的剖腹产比例的决定因素。关键词：剖腹产, 探索性空间数据分析, 医疗地理学, 空间统计。

El uso excesivo de las operaciones cesáreas (C-sections) en los Estados Unidos es un asunto muy disputado. La tasa de nacimientos por cesárea en 2015 del 32 por ciento estuvo por encima del doble de lo recomendado por la Organización Mundial de la Salud, que es del 10 al 15 por ciento. Nosotros empleamos métodos estadísticos espaciales y técnicas de visualización de datos para evaluar las tendencias temporales y espaciales de las tasas de cesárea por condado a través de los Estados Unidos. Aunque la tasa nacional de cesáreas permaneció estable al comienzo y al final del período de este estudio, un incremento en las tasas de 1997 al 2009 se reflejó simultáneamente en las tasas a nivel nacional, estatal y de condados individuales. Los indicadores locales de la dependencia espacial no muestran concentración espacial que indique conexión con el cambio, o que lo oriente, pero los métodos de visualización usados aquí muestran detalles sobre la desviación de las tendencias temporales locales en condados individuales. Al destacar los condados que no siguen las tendencias de sus vecinos, identificamos localizaciones excepcionales que podrían ayudarlos a impulsar estudios de los determinantes de las tasas cambiantes de cesáreas en los Estados Unidos.

Palabras clave:

• análisis de datos espaciales
• estadísticas espaciales
• geografía médica
• secciones cesáreas.

Acknowledgments

This work was made possible thanks to the von Dreden Stacey research grant for undergraduate students at the University of Colorado and thanks to Phil White, Earth Sciences Librarian of the University of Colorado.

Additional information

KATHLEEN R. WEIMER is an Administrator at the Dana Farber Cancer Institute, Boston, MA 02215. E-mail: [email protected]. Her research interests include how medical systems change as well as their exchanges with and their effects on population health.

CARSON J. Q. FARMER is an Assistant Professor of Geography at the University of Colorado, Boulder, CO 80304. E-mail: [email protected]. His research interests include GIScience and spatial analysis, with a focus on spatial–temporal dynamics, falling under the general banner of computational GIScience and encompassing work on networks, transportation, big data, snow and water processes, and geospatial algorithms.

COLLEEN E. REID is an Assistant Professor of Geography at the University of Colorado, Boulder, CO 80304. E-mail: [email protected]. Her research interests include how environmental and social exposures interact to influence health with a particular focus on exposures caused by global climatic changes and society’s responses to those changes, including the health impacts of exposure to air pollution from wildfires, extreme heat events, and proximity to urban vegetation.