Transportation-Related Carbon Footprint of Coronary Heart Disease Ambulatory Care in the United States

HomeCirculation ResearchVol. 134, No. 9Transportation-Related Carbon Footprint of Coronary Heart Disease Ambulatory Care in the United States Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBTransportation-Related Carbon Footprint of Coronary Heart Disease Ambulatory Care in the United States Pedro R.V.O. Salerno, Zhuo Chen, Brendan Bourges-Sevenier, Alice Qian, Salil Deo, Khurram Nasir, Sanjay Rajagopalan and Sadeer Al-Kindi Pedro R.V.O. SalernoPedro R.V.O. Salerno https://orcid.org/0000-0002-5116-5062 Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, OH (P.R.V.O.S., Z.C., S.R.). , Zhuo ChenZhuo Chen Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, OH (P.R.V.O.S., Z.C., S.R.). Case Western Reserve University School of Medicine, Cleveland, OH (Z.C., B.B.-S., S.D., S.R.). , Brendan Bourges-SevenierBrendan Bourges-Sevenier https://orcid.org/0009-0002-3618-6970 Case Western Reserve University School of Medicine, Cleveland, OH (Z.C., B.B.-S., S.D., S.R.). , Alice QianAlice Qian Surgical Services, Louis Stokes VA Medical Center, Cleveland, OH (A.Q., S.D.). , Salil DeoSalil Deo https://orcid.org/0000-0002-4729-1461 Case Western Reserve University School of Medicine, Cleveland, OH (Z.C., B.B.-S., S.D., S.R.). Surgical Services, Louis Stokes VA Medical Center, Cleveland, OH (A.Q., S.D.). , Khurram NasirKhurram Nasir https://orcid.org/0000-0001-5376-2269 Center for Health and Nature and Department of Cardiology, Houston Methodist Hospital, TX (K.N., S.A.-K.). , Sanjay RajagopalanSanjay Rajagopalan https://orcid.org/0000-0001-6669-8163 Harrington Heart and Vascular Institute, University Hospitals Cleveland Medical Center, OH (P.R.V.O.S., Z.C., S.R.). Case Western Reserve University School of Medicine, Cleveland, OH (Z.C., B.B.-S., S.D., S.R.). and Sadeer Al-KindiSadeer Al-Kindi Correspondence to: Sadeer Al-Kindi, MD, FACC, Center for Health and Nature, Houston Methodist Hospital, 6550 Fannin St, Ste 1801, Houston, TX 77030. Email E-mail Address: [email protected] https://orcid.org/0000-0002-1122-7695 Center for Health and Nature and Department of Cardiology, Houston Methodist Hospital, TX (K.N., S.A.-K.). Originally published25 Apr 2024https://doi.org/10.1161/CIRCRESAHA.124.324330Circulation Research. 2024;134:1218–1220As the leading cause of death in the United States, managing coronary heart disease (CHD) is not only a critical objective of the health care system but also a source of resource utilization. With the United States emitting a quarter of the world's health care-related carbon footprint, the impact of health care access on travel-related carbon emissions must also be examined.1,2 Thus, we investigated the transport-related carbon emissions for routine ambulatory care for CHD in the United States.We obtained data on the crude prevalence (%) of CHD (patients aged ≥18 years) from the Centers for Disease Control PLACES database 2022. National Provider Identifier records from the National Plan and Provider Enumeration System were obtained in July 2023. We identified cardiologists and their practice business addresses (geocoded to longitude and latitude). We calculated the Haversine distance between each census tract (CT) centroid (2010 census) and the nearest cardiologist. We obtained the estimated CO2 emissions from a typical passenger vehicle from the Environmental Protection Agency: tailpipe CO2 emission of 248.55 g per km, based on a fuel consumption of 1 gallon per 35.73 km.3 CTs were considered urban if they had at least 2000 housing units or had a population of at least 5000 (Census Bureau). We obtained the 2018 social vulnerability index from the Agency for Toxic Substances and Disease Registry. The social vulnerability index is a measure that provides a relative indication of the vulnerability of CTs based on 16 social factors, with greater values indicating increased vulnerability.We calculated the total CT tailgate CO2 emissions in metric tons (MTCO2) for a round trip to the nearest cardiologist, referred to as CHD ambulatory care transport–related carbon footprint (ACT-CF) in this article, per year, calculated as follows:[(CTdistanceinKmtonearestcardiologist)∗248.55gCO2∗(numberofindividualswithCHDintheCT)∗21,000,000]The estimated number of individuals in a CT with CHD was obtained by multiplying the crude CHD prevalence (%) by the adult CT population. We reported the national estimate of the ACT-CF as the median and interquartile range (IQR), weighted by the number of individuals with CHD in the CT. We reported results separately for rural and urban CT and stratified our analysis by social vulnerability index quartiles. As a comparator, we estimated the total and national median emissions if the follow-up was provided by primary care providers (defined as internal medicine or family medicine specialty). We used R, version 4.3.0, for statistical analyses and maps. Due to the use of publicly available data, ethical approval was not required.The ACT-CF was calculated and mapped for 13 381 715 patients with CHD in 69 328 CTs linked with 49 587 cardiologists in the contiguous United States (Figure [A]), totaling 63 005 MTCO2. Patients residing in urban CTs contributed 27 892 MTCO2 and rural CTs contributed 35 113 MTCO2. The national median ACT-CF was 0.42 MTCO2 (IQR, 0.17–1.31). For urban CTs (10 309 198 patients with CHD), median emissions were 0.29 MTCO2 (IQR, 0.13–0.61), while for rural residents (3 072 517 patients with CHD), it was 2.13 MTCO2 (IQR, 1.26–3.59). Figure (B) shows the median ACT-CF by social vulnerability index quartile according to urban and rural settings. In comparison, emissions would total 21 747 MTCO2, with a national median of 0.16 MTCO2 (IQR, 0.07–0.46) if patients had a similar number of visits with the nearest primary care provider.Download figureDownload PowerPointFigure. Spatial and social disparities in estimated carbon footprint associated with coronary heart disease (CHD) patients' travel to cardiologists. A, Map of the census tract-level tailpipe CO2 emissions in metric tons (MTCO2) associated with patients with CHD traveling to the nearest cardiologists (CHD ambulatory care transport–related carbon footprint). B, CHD ambulatory care transport–related carbon footprint stratified by setting and according to social vulnerability index (SVI) quartiles.We identified substantial heterogeneity between urban and rural emissions, with rural residents emitting ≈7.3× more tailpipe emissions than urban residents, likely due to longer commutes. The total ACT-CF for patients with CHD in the United States is equivalent to powering over 12 000 homes annually. To offset this carbon, over 75 000 acres of forest would be needed.3 As a result, possible measures to offset these carbon emissions must be envisioned. One strategy involves improving preventive care to reduce specialty health care visits. Additionally, communities with high levels of social vulnerability suffer from the paradox of poor access and yet needing higher acuity care. Recent advancements in telemedicine with televisits and home monitoring devices (eg, blood pressure) and even remote electrocardiography and ultrasonography may provide an avenue to improve health care access while reducing the environmental footprint of health care. While telemedicine usage may increase electricity consumption, this carbon footprint is much lower than that of transportation-related emissions.2Typically, individuals in affluent areas with higher socioeconomic status emit more CO2, due to higher consumption.4 However, our results demonstrate that patients in vulnerable and rural areas, given the longer distances to cardiovascular care, inevitably produce greater vehicle emissions owing to reduced geographic proximity to cardiologists. Additionally, rural socioeconomically disadvantaged populations may have higher CHD prevalence and morbidity compared with their urban counterparts, potentially leading to more frequent follow-up visits.5In conclusion, ambulatory care for CHD in the United States is a considerable source of traffic-related greenhouse gas emissions particularly in rural areas with higher social vulnerability. Exploring responsible mitigation strategies to reduce these emissions, while ensuring adequate health care, must be a priority.ARTICLE INFORMATIONData AvailabilityThe data that support the findings of this study are available from the corresponding author upon reasonable request.Sources of FundingNone.Nonstandard Abbreviations and AcronymsACT-CFcoronary heart disease ambulatory care transport–related carbon footprintCTcensus tractIQRinterquartile rangeMTCO2CO2 emissions in metric tonsDisclosures None.FootnotesFor Sources of Funding and Disclosures, see page 1220.Correspondence to: Sadeer Al-Kindi, MD, FACC, Center for Health and Nature, Houston Methodist Hospital, 6550 Fannin St, Ste 1801, Houston, TX 77030. Email sal-kindi@houstonmethodist.orgREFERENCES1. Eckelman MJ, Huang K, Lagasse R, Senay E, Dubrow R, Sherman JD. Health care pollution and public health damage in the United States: an update.Health Aff (Millwood). 2020; 39:2071–2079. doi: 10.1377/hlthaff.2020.01247CrossrefMedlineGoogle Scholar2. Purohit A, Smith J, Hibble A. Does telemedicine reduce the carbon footprint of healthcare? A systematic review.Future Healthc J. 2021; 8:e85–e91. doi: 10.7861/fhj.2020-0080CrossrefMedlineGoogle Scholar3. US EPA O. Greenhouse Gas Equivalencies Calculator.2015. Accessed January 24, 2024. https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculatorGoogle Scholar4. Nielsen KS, Nicholas KA, Creutzig F, Dietz T, Stern PC. The role of high-socioeconomic-status people in locking in or rapidly reducing energy-driven greenhouse gas emissions.Nat Energy. 2021; 6:1011–1016. doi: 10.1038/s41560-021-00900-yCrossrefGoogle Scholar5. Cross SH, Mehra MR, Bhatt DL, Nasir K, O'Donnell CJ, Califf RM, Warraich HJ. Rural-Urban differences in cardiovascular mortality in the US, 1999-2017.JAMA. 2020; 323:1852–1854. doi: 10.1001/jama.2020.2047CrossrefMedlineGoogle Scholar eLetters(0)eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate.Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page.Sign In to Submit a Response to This Article Previous Back to top Next FiguresReferencesRelatedDetails April 26, 2024Vol 134, Issue 9 Advertisement Article InformationMetrics © 2024 American Heart Association, Inc.https://doi.org/10.1161/CIRCRESAHA.124.324330PMID: 38662867 Originally publishedApril 25, 2024 Keywordscarbon footprintcardiologycardiovascular diseasessocial determinants of healthPDF download Advertisement SubjectsCardiovascular DiseaseDisparitiesEpidemiology