Impact of Telemedicine Use on Outpatient-Related CO2 Emissions: Estimate From a National Cohort

ABSTRACT

Objective: The US health care system contributes to approximately 9% of domestic US greenhouse gas emissions, exacerbating climate change and threatening human health. By substituting for in-person visits, telemedicine may represent a means of emission avoidance.

Study Design: Leveraging multipayer claims data, we developed models based on various assumptions to estimate ranges of emissions from travel averted by telemedicine utilization between April 1, 2023, and June 30, 2023.

Methods: We estimated the carbon dioxide (CO₂) emissions averted from the avoidance of travel by patients using telemedicine as a substitute for their usual source of in-person care at post–public health emergency rates through a modeling analysis of nationwide multipayer claims data representing 19% of US insured adults; findings were extrapolated to the entire US insured adult population.

Results: We quantified a monthly average of 1,481,530 US telemedicine visits (65,733 rural) during the study period. Between 740,765 and 1,348,192 of these were estimated to have substituted for in-person visits. Using inputs of 2021 electric vehicle (EV) production share and emissions per mile, we estimated that between 4,075,065 and 7,489,486 kg of CO₂ are averted due to telemedicine use each month. Estimates accounting for different assumptions including EV and public transportation use produce a range of 4 million (most conservative) to 8.9 million (least conservative) kg of CO₂ averted per month. Extrapolating to the entire US adult population, we estimate that monthly emissions averted range from 21.4 to 47.6 million kg of CO₂—roughly equivalent to the monthly emissions of 61,255 to 130,076 gasoline-powered passenger vehicles.

Conclusion: Our results suggest that telemedicine use at 2023 rates modestly decreases the carbon footprint of US health care delivery.

Am J Manag Care. 2025;31(9):In Press

Takeaway Points

Our findings suggest that telemedicine use at 2023 rates modestly decreases the carbon footprint of US health care delivery.

• Reducing the carbon footprint of US health care will have positive downstream effects on human health.
• Our most conservative estimates show that 2023 telemedicine utilization led to a monthly avoidance of 4 million kg of carbon dioxide in our nationwide sample—emissions equivalent to 61,255 passenger vehicles.
• Policy makers and payers should recognize the positive environmental impact of telemedicine utilization when considering future policies that might impact access to, and reimbursement of, telemedicine.

The US health care system contributes to nearly 9% of domestic US greenhouse gas emissions,^1,2 exacerbating climate change and potentially threatening human health with more extreme weather events, changes in the distribution of vector-borne diseases, and disruption of food systems.³ Because transportation accounts for more than 28% of total US greenhouse gas emissions⁴ and the use of telemedicine decreases the need to use transportation, telemedicine has the potential to diminish the environmental impact of health care delivery—particularly for frequent, routine visits in rural settings.

Although the utilization and clinical impact of the increased use of telemedicine associated with the COVID-19 public health emergency (PHE) have been examined, it is unknown how this wholesale structural change in care delivery impacted carbon dioxide (CO₂) emissions—a major component of greenhouse gas emissions.^4,5 We estimated the CO₂ emissions averted from patients’ avoidance of travel by using telemedicine, at post-PHE utilization rates, as a substitute for their usual source of in-person care.

METHODS

The primary data source is the Milliman MedInsight Emerging Experience deidentified research database (eAppendix Methods and eAppendix Figure 1 [eAppendix available at ajmc.com]), which has been previously used to study national health care utilization patterns.^6-9 Our cohort included 44.7 million US adults enrolled in Medicare fee-for-service, Medicare Advantage, Medicare-Medicaid (dual-eligible), Medicaid, or commercial plans across all 50 US states, representing approximately 19% of the insured US adult population. We determined the mean monthly counts of telemedicine visits in our cohort, stratified by rurality, from April 1, 2023, to June 30, 2023. We chose to use the most recently available quarter of data, which was more likely to reflect a post-PHE state of telemedicine use than earlier periods.

To estimate the emissions averted, we multiplied the number of in-person visits avoided by the mean distance driven to patients’ usual source of care and the CO₂ emissions per mile generated by an average passenger car. For the base estimate of in-person visits avoided, we multiplied the total counts of telemedicine visits by a substitution ratio derived by Reed et al,¹⁰ who found that 9.3% of telemedicine visits had an in-person primary care physician visit, an emergency department visit, or a hospitalization in the following 7 days; conservatively assuming that, without telemedicine, in-person visits would have 0 follow-up visits within 7 days (reported rate was 3.1%) would suggest that 91% of telemedicine visits likely substituted for an in-person visit (eAppendix Figure 2). We also calculated a more conservative scenario in which we assumed that only 50% of the telemedicine visits substituted for otherwise in-person visits (eAppendix Figure 3).

Mean driving distance to patients’ usual source of in-person care was derived from the 2017 National Household Travel Survey,¹¹ stratified by rurality. In addition to our base estimate, we also used the following inputs to produce lower-bound estimates of CO₂ emissions averted per mile traveled: (1) lower mean emissions per mile driven (eg, visits with unknown rurality were conservatively combined with visits from urban areas, which had shorter driving distances); (2) accounted for the shares of different vehicle types, determined from market share data from the 2022 Environmental Protection Agency Automotive Trends Report¹² (ie, higher proportion of electric vehicles [EVs] that produce lower CO₂ emissions); and (3) accounted for the use of low-emission public transportation, derived from the 2022 Congressional Budget Office report on transportation sector emissions.¹³ Emissions produced by a telemedicine visit were derived from Stanford Health Care carbon life cycle data.¹⁴ Parameters used in the calculations are presented in the Table.^10-17

RESULTS

In our data set representing approximately 19% of the 238 million insured US adults,¹⁸ there was a monthly mean of 1,481,530 telemedicine visits between April 1, 2023, and June 30, 2023, of which 65,733 were in rural areas. Assuming substitution ratios of 0.5 to 0.91 suggests that 740,765 to 1,348,192 telemedicine visits substituted for in-person visits, respectively. eAppendix Figure 2 shows the base calculation for CO₂ emissions averted and a flowchart that shows lower- and higher-bound estimates that account for alternative assumptions for the parameters (results with the lower 0.5 substitution factor are found in the Figure and in eAppendix Figure 3). Using inputs of 2021 EV production share and emissions per mile, we estimated that between 4,075,065 and 7,489,486 kg of CO₂ are averted monthly. Estimates accounting for different assumptions including EV and public transportation use produce a range of 4 million (most conservative) to 8.9 million (least conservative) kg of CO₂ per month. Extrapolating these findings from our sample to the entire insured US adult population, we estimate that monthly emissions averted range from 21.4 million to 47.6 million kg of CO₂; these are roughly equivalent to the monthly emissions of 61,255 to 130,076 gasoline-powered passenger vehicles or to recycling 7447.1 to 16,543.5 tons of waste or 1.8 million to 4 million trash bags per month.¹⁹

DISCUSSION

Our results suggest that telemedicine use at 2023 rates modestly decreases the carbon footprint of US health care delivery. A recent modeling study suggests that adding 4.4 million kg of CO₂ annually causes 1 temperature-related excess death globally, not including deaths from other climate-mortality pathways such as increased pollution, spread of infectious diseases, disruptions to food supply, and flooding.²⁰ Nevertheless, although we estimated averted emissions equivalent to 61,255 to 130,076 internal combustion passenger vehicles, more than 98 million automobiles were registered in the US in 2022.²¹

To date, discussions on telemedicine use in the US have mostly revolved around the issues of access, reimbursements, regulations, spending, and quality of care.^22,23 Although these are important considerations, increased attention to telemedicine’s environmental impact is warranted to better inform the health policy discourse. Our estimates represent meaningful reductions in total US greenhouse gas emissions, demonstrating how telemedicine use provides a significant opportunity to reduce CO₂ emissions and ultimately improve human health.

Future studies may explore whether telemedicine has more or less environmental impact on particular health care systems or within particular specialties or types of service (ie, whether telemedicine disproportionately replaced services that were responsible for relatively fewer CO₂ emissions before the expansion of telemedicine flexibilities).¹⁴ Questions also remain about whether the benefit of telemedicine’s estimated environmental impact outweighs any potential trade-offs with respect to quality of care,²⁴ particularly when adjusted for the learning curves associated with new technological paradigms. Finally, future researchers may also be interested in estimating the impact of renewable energy–focused policy incentives on greenhouse gas emissions.

Limitations

This study has limitations. First, we used a cross-sectional convenience sample, potentially limiting the representativeness of the study cohort. Because of this, we were not capable of estimating key health outcomes such as excess deaths without introducing additional assumptions. Nevertheless, our prior work demonstrated that the 44.7 million adults in the Milliman MedInsight Research Database have similar sociodemographic characteristics compared with US Census Bureau estimates.⁶ Although we are intentionally conservative and transparent in estimating several of our inputs, these assumptions—and ultimately our findings—reflect averages and may not account for possible regional variation beyond rurality, such as seasonal trends or other regional variation based on broadband access or age or combinations thereof.

Second, because we based mean driving distance to in-person care and vehicle market share on estimates in prior literature utilizing non-2023 data, the data sources we used for the estimates may not accurately represent the 2023 status quo. Nevertheless, mean driving distance to in-person care remained remarkably consistent from 2001 to 2017.¹¹ Given that most midpandemic housing movement was temporary,²⁵ 2017 mean distances are unlikely to substantively differ from those in 2023.

Third, we acknowledge that recent trends show decreases in telemedicine use from pandemic-era highs, so our estimates may represent an overestimation of emissions averted in the future. Hence, these findings are subject to variations in the rate of telemedicine use due to changes in delivery patterns that may occur because of an evolving policy discussion that may impact utilization, such as changes in consumer cost sharing, clinician reimbursement, or visit composition. If, for instance, telemedicine replaced disproportionately more visits that did not require travel time prior to the introduction of flexibilities, then our upper-bound estimates may reflect overestimations. Nevertheless, our own data and those from other studies suggest that telemedicine reached a steady state in 2021.^10,26

CONCLUSIONS

The rapid growth of telemedicine afforded convenient access to medical care and clinical benefits to millions of Americans. An important yet understudied aspect of telemedicine use is its environmental impact. The most conservative lower bound of our findings suggests that telemedicine use at 2023 rates modestly decreases the CO₂ emissions of US health care delivery. Given this, policy makers and payers should recognize the positive environmental impact of telemedicine utilization when considering future policies that might impact access to, and reimbursement for, telemedicine.

Acknowledgments

A. Mark Fendrick, MD, and John N. Mafi, MD, MPH, contributed equally to this work and are listed as co–senior authors. The authors would also like to acknowledge Lucia Chen, MS for her statistical support.

Data Availability Statement

The authors agree to make any further calculations or aggregated, deidentified data from this study available for any interested researchers upon request. Due to the terms of the data use agreement with Milliman MedInsight, the authors had no direct access to the proprietary, raw Emerging Experience Research Database data used to generate the aggregated study cohort. The authors would therefore be unable to make those data available.

Author Affiliations: Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine, UCLA (BD, AR, MCu, CHT, CAS, JNM), Los Angeles, CA; Milliman (MCr, DS, MH), Seattle, WA; RAND (CLD, JNM), Santa Monica, CA; Division of General Internal Medicine, University of Michigan Medical School (AMF), Ann Arbor, MI; Department of Health Management and Policy, University of Michigan School of Public Health (AMF), Ann Arbor, MI.

Source of Funding: None.

Author Disclosures: Mr Romanov, Ms Cui, and Dr Mafi were financially supported by the National Institutes of Health (NIH)/National Institute on Aging (NIA) K76 Career Development Award. Dr Craff, Mr Skinner, and Mr Hadfield are all employees of Milliman. Dr Sarkisian reports grants from the NIH during the conduct of the study. Dr Fendrick reports serving as a consultant to AbbVie, CareFirst BlueCross BlueShield, Centivo, Community Oncology Alliance, EmblemHealth, Employee Benefit Research Institute, Exact Sciences, Grail, Health at Scale Technologies,* HealthCorum, Hopewell Fund, Hygieia, Johnson & Johnson, Medtronic, MedZed, Merck, Mother Goose Health,* Phathom Pharmaceuticals, Proton Intelligence, RA Capital Management, Sempre Health,* Silver Fern Healthcare,* Teladoc Health, US Department of Defense, Virginia Center for Health Innovation, Washington Health Benefit Exchange, Wellth,* Yale New Haven Health System, and Zansors* (asterisks indicate equity interest); research funding from Arnold Ventures, National Pharmaceutical Council, Patient-Centered Outcomes Research Institute, Pharmaceutical Research and Manufacturers of America, and Robert Wood Johnson Foundation; and outside positions as co–editor in chief of The American Journal of Managed Care, past member of the Medicare Evidence Development & Coverage Advisory Committee, and partner at VBID Health, LLC. Dr Mafi reports grants from NIA during the conduct of the study as well as nonfinancial support from Milliman MedInsight and grants from Arnold Ventures and Commonwealth Fund. Dr Mafi has also provided unpaid consulting to Milliman MedInsight and the Agency for Healthcare Research and Quality. The remaining authors report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Authorship Information: Concept and design (BD, MCr, MH, AMF, JNM); acquisition of data (AR, MCu, MCr, DS, MH, JNM); analysis and interpretation of data (BD, AR, MCu, CHT, MCr, DS, CAS, CLD, AMF, JNM); drafting of the manuscript (BD, AR, CLD, AMF, JNM); critical revision of the manuscript for important intellectual content (BD, AR, MCu, CHT, CAS, CLD, AMF, JNM); statistical analysis (BD, CHT, JNM); provision of patients or study materials (JNM); obtaining funding (CAS, JNM); administrative, technical, or logistic support (AR, MCr, DS, MH, JNM); and supervision (AMF, JNM).

Address Correspondence to: John N. Mafi, MD, MPH, Division of General Internal Medicine and Health Services Research, David Geffen School of Medicine, UCLA, 1100 Glendon Ave #908, Los Angeles, CA 90024. Email: jmafi@mednet.ucla.edu.

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