#2769 The impact of carbon footprint in advanced chronic kidney disease treatments
Authors: Francés Francesc Moncho , Calatayud Susana Lomas , Giménez-Civera Elena , Gandia Lorena , Montesa Maria Jesus Puchades , Forquet Claudia , Candia Boris Marcelo Gonzales , Montomoli Marco , Velásquez Caterina Rodriguez , Nemiña María Belén Aguilar-Uriarte , Gonzalez Nayara Panizo , Teruel Jose Luis Górriz 
Published: May 2024

Abstract

Background and Aims
Climate change has been classified as “the greatest global threat to health in the 21st century”. The quantification of the carbon footprint (CF) currently stands as the most accepted model for assessing the ecological impact of various businesses and healthcare systems. Renal treatments have a significant impact on the CF of healthcare systems, especially in terms of supple chains and waste management. The choice of the most environmentally friendly treatment for pathologies arising from advanced chronic kidney disease (ACKD) or peritoneal dialysis (PD) can impact the amount of waste generated and energy consumed.
The objective was to analyze the carbon footprint (CF) impact resulting from the use of two different drugs in patients with the same medical condition: advanced chronic kidney disease (ACKD) or peritoneal dialysis (PD). One group received cinacalcet and another group received subcutaneous darbepoetin.

Method
Transversal observational study including 41 patients (19 receiving cinacalcet and 22 received darbepoetin alfa) that collected medication from the hospital pharmacy from February 1 to March 30, 2023.
The CF was calculated using analytical techniques from hybrid life cycle models of the analyzed medications. For this analysis, three groups were considered: patient travel (distance traveled, trips/year, pickup, mode of transportation, and type of fuel), energy (energy consumption for refrigeration), and waste disposal and transportation (self-administration or administration by a family member, disposal location, and recycling information received).
Quantification was performed using the formula: activity x emission factor (activity = sum of CF of the variables composing each group, emission factor = constant provided by the “Ministerio de transición ecológica” database: https://www.miteco.gob.es/es/cambio-climatico).

Results
Forty-one patients were included with a median age of 72 years [IQR 63-80]. Twenty-seven patients (65%) were male and 28 (68%) were on PD. Nineteen patients (46%) were on treatment with cinacalcet and 22 (54%) with darbepoetin alfa. There were no differences in calcium, phosphorus, parathormone or hemoglobin within the groups.
Overall impact:
The overall impact of the CF derived from the subcutaneous treatment process with darbepoetin alfa was 95,512.93 kg of CO2/year compared to that derived from cinacalcet treatment, which was 12,199.85 kg of CO2/year (p&lt; 0.001) (Fig. 1).
Patient travel to hospital and transportation of supplies
Group-wise analysis did not detect significant differences in consumption derived from patient's travel to collect darbepoetin alfa or cinacalcet in the hospital (15.97 [IQR 5.25-28.66] vs 10.20 [IQR 2.08-24.5] kg CO2/year, p = 0.45).
The CF of transporting supplies of darbepoetin alfa was 41,526.15 kg CO2/year compared with 10,361.54 kg CO2/year in cinacalcet group.
Waste generation and transportation
The waste derived CF of patients treated with darbepoetin alfa was 132 kg CO2/year [IQR 93.5-143] compared to patients treated with cinacalcet 36.4 kg CO2/year [IQR 36.3-36.5] with p-value &lt; 0,001. Moreover, the transportation of waste for darbepoetin alfa resulted in a carbon footprint of 42,224.55 kg CO2/year, mainly attributable to the disposal of sharp waste.
Energy:
The refrigeration of darbepoetin alfa was calculated with a total emission of 8,286.96 kg CO2. Cinacalcet treatment did not require any refrigeration.

Conclusion
The CF derived from the subcutaneous administration of darbepoetin alfa was significantly greater than the CF derived from oral medication like cinacalcet. This may represent a negative environmental impact of the administration of medications via the subcutaneous route compared to oral medications in this group of patients.
The use of drugs that do not require subcutaneous administration could be more sustainable, reducing the carbon footprint by 85%, as they do not require refrigeration or waste incineration.