The number of patients with chronic kidney disease is growing worldwide (1) as well as in Japan (2). Dialysis therapy is essential for patients with end-stage kidney disease, and global demand is expected to increase (3). Hemodialysis is a resource-intensive healthcare, especially at the point of care (4). In France and Australia, the amounts of electricity and water consumed, and the waste generated per session have been estimated as approximately 7–16 kWh, 370–380 L, and 1.1 kg, respectively (5, 6). Therefore, the economic costs associated with providing this therapy must be considered to ensure the sustainability of dialysis services (7).

The concept of “Green Dialysis”, which addresses environmental concerns related to dialysis therapy that consumes large amounts of resources, has gained widespread acceptance (8, 9). The metric that converts greenhouse gases (the cause of global warming) into CO₂ equivalents is termed the carbon footprint (CFP). The CFP of healthcare has shown a generally increasing trend, accounting for approximately 4.6% of annual global carbon emissions in 2011 and 6.1% in 2019 (10, 11). Healthcare is thus emerging as one of the most carbon-intensive service sectors and a major contributor to climate change (12). The annual CFP per patient receiving dialysis therapy has been estimated as 3.9 tCO₂e, compared with 0.31 tCO₂e in individuals without dialysis (13). Efforts are also underway to mitigate the environmental impact of dialysis treatment by reducing resource consumption. For example, in France, monthly data collection (eco-reporting) was implemented in hemodialysis centers in 2005, successfully reducing power and water consumption by 29.6% (from 23.1 to 16.26 kWh/session) and 52% (from 801 to 382 L/session), respectively (5). Care-related waste decreased from 1.8 to 1.1 kg as a result of regular staff training. Across a cohort of 2,642 patients, an estimated 102,440 tCO₂e of carbon savings were achieved, equivalent to the CO₂ emissions produced by a plane flying around the globe 11,500 times (5). These findings demonstrate that visualizing and monitoring resource consumption in dialysis can drive practice improvements and promote behavioral change among staff, leading to resource conservation.

The clinic in this study provides in-center hemodialysis therapy, but not home dialysis, peritoneal dialysis, or transplantation, in a regional city. Since initiating hemodialysis services in 1978, the clinic has maintained financially stable operations primarily through dialysis practices, implementing economical resource-saving measures across all departments. We aimed to achieve Green Dialysis by assessing sequential changes in resource consumption from both in economic and environmental perspectives and identifying effective strategies to reduce quantitative burdens, in the first such initiative in Japan.

Medical institutions need to pursue profit for business sustainability; thus, the activities of the resource-saving committee primarily aim to reduce economic burden. In recent years, addressing environmental issues has gained increasing attention. From a corporate social responsibility (CSR) perspective, conservation and energy efficiency have also become critical initiatives for healthcare professionals. The facility in this study did not increase overall resource consumptions and environmental impact during the period from 2016 to 2024. The CFP for electricity consumption has remained unchanged, while the CFP for gas and water consumption has decreased over time. However, it is possible that these achievements have been offset by the significant increase in the environmental cost of waste disposal or the impact of additional amount of infectious waste due to COVID-19. To rigorously prove causation, it would be preferable to compare the facility with another that did not implement resource-saving measures during the same period, or to compare with survey results from before the facility's initiatives began. However, due to limitations in the information collected for this survey, this could not be examined.

Our investigation revealed the median consumption of electricity, gas, and water per hemodialysis patient: monthly electricity consumption was approximately 353 kWh, gas consumption was 17 m³, and water consumption was 9 m³. For comparison, the monthly average resource consumption per average household in Japan is as follows: 329 kWh of electricity, 16 m³ of gas, and 9 m³ of water per capita (16, 17). Put simply, we are constantly consuming one additional set of household resources daily to sustain the life of a patient with end-stage kidney disease: a fact that healthcare providers involved in dialysis therapy must recognize. In a society where resources are secure, dialysis care can be provided, so this reality remains hidden. However, disasters are an exception. The clinic in this study was affected by the 2011 Great East Japan Earthquake and has experience providing dialysis during major disasters. As part of business continuity plan measures, reducing energy consumption during emergencies is essential because medical facilities have the predominant mission of maintaining operations even during disasters to serve the community and protect lives. We consider it is critically important to practice conservation and energy efficiency on a daily basis to sustain medical facilities when relying on limited emergency self-generated power sources.

From an economical perspective, although all staff members have worked together and succeeded in implementing daily cost-saving measures, the reality is that expenses remain strained by soaring utility costs and rising prices. The main reasons for the surge in purchased electricity costs are rising international fuel prices, depreciation of the yen, increased surcharges for renewable energy adoption, and tight electricity supply and demand. Efforts to curb rising utility costs within the healthcare sector are considered difficult. Despite requiring some initial investment, measures such as improving the energy efficiency of medical equipment, implementing on-site power generation (18), conserving gas and water through heat recovery systems, and reducing unnecessary disinfection water usage in dialysis equipment will become increasingly necessary. These measures will also likely become new priorities for the healthcare industry. It is also necessary for the dialysis clinics to make the management decision to introduce energy-saving and low-environmental-impact initiatives. In addition to publishing this paper, it is believed that information sharing among physicians through study groups and the expansion of subsidy programs for introducing equipment will be necessary.

Research examining the sustainability of dialysis therapy from an environmental perspective has increased significantly in recent years. However, the lack of internationally comparable data stems from the absence of appropriate environmental inventories in healthcare. In the present analysis, it was relatively easy to calculate the carbon footprints for electricity, gas, and water services because the corresponding unit costs for the relevant time period were publicly available. In contrast, the carbon footprint for medical waste disposal is still unavailable in Japan. We can refer to a pioneering case study regarding environmental assessment for healthcare, conducted in England (19). In that study, the CFP per unit of hospital waste disposal varied because different base units were assigned depending on the treatment process, and none matched the current review. For example, infectious waste generates 338 kg CO₂e/ton from autoclave decontamination, 167 kg CO₂e/ton from low temperature incineration, and 64 kg CO₂e/ton from transportation, totaling 569 kgCO₂e/ton of waste. This clearly demonstrates that infectious waste accounts for a much higher CFP than general waste, which is typically incinerated or landfilled. The ideal method to reduce the weight of medical waste in hemodialysis therapy is to recycle dialysis membranes and circuits, but this is not currently practical due to economic costs, infection risks, and ethical considerations (20). Therefore, efforts by industry, such as reducing the weight of dialysis membrane housings and redesigning circuits, are also required.

Although not discussed at meetings of the resource-saving committee in the clinic, advanced facilities are aiming to reduce environmental impact by individualizing and optimizing dialysate volume. In Japan as well, reducing the dialysate flow rate (Qd) to 400 ml/min during hemofiltration dialysis according to the patient's physical condition and residual renal function has been adopted in clinical practice (21). A blood flow rate (Qb) to Qd ratio of approximately 1:2 is considered efficient, and the Qd is occasionally adjusted accordingly in our experience. Regarding optimization of Qd, a single-center, nonrandomized, open-label, cross-over pilot trial involving 30 hemodialysis patients in India demonstrated a water conservation strategy by increasing dialysate temperature while reducing Qd without compromising the adequacy and safety of dialysis in young and hemodynamically stable patients (22). In that study, reducing the Qd from 500 ml/min to 300 ml/min achieved a 40% reduction in water consumption (22). Recently, discussions have begun and intensified within Japanese dialysis-related academic societies regarding the individual optimization of Qd in hemodiafiltration. We need to pay attention to this as an attempt to reduce the total volume of dialysate used indiscriminately, without causing adverse health effects.

Furthermore, if these resource-saving efforts extend to healthcare providers and to patients' households, they will make an important contribution to healthcare sustainability. From an environmental perspective, reducing wasteful consumption also allows us to play a vital role under any circumstances. In 2023, Japan conducted its first environmental awareness survey for dialysis facilities, the “Green Survey” (23). The results revealed that environmental awareness was not still high among Japanese dialysis staff, and few have implemented environmental actions. In four-fifths of the facilities (n = 208/255, 81.6%), no “green team” or resource-saving committee had been formed to promote environmental protection. As more environmentally conscious healthcare professionals emerge, it is hoped that patient-optimized dialysis care can be achieved through cooperation and understanding among physicians, healthcare staff, patients, and dialysis-related companies.