International context

The Netherlands is not the first country to consider taking into account environmental impact in health care decision making. England’s National Institute for Health and Care Excellence has for some time been engaged in studies of the feasibility of evaluating the environmental impacts of pharmaceuticals and medical interventions (8). Similarly, Canada’s Drug Agency is doing research into criteria that can serve as a guideline when an environmental assessment should be part of the decision-making process for a health technology (9). The guidelines of the Medical Services Advisory Committee in Australia include a statement that “[i]f there are particular concerns about the environmental impacts of the proposed health technology, or a significant advantage in the way the proposed technology reduces environmental impact compared to the comparator, these can be outlined” (10) (p. 229). A recent article issued by the Environmental Sustainability in HTA Working Group (ESHTA) concludes that integrating environmental sustainability into health technology assessment may help make health care more sustainable, but that further work is necessary to allow ecological sustainability to be actually used in healthcare decision making (Reference Holtorf, Pegg, Mueller and McMeekin11).

While we agree that more research is necessary, we also believe that the severity of the impending ecological crisis requires us to start moving ahead based on what we do know and what we can do. There is an abundant scientific literature on the environmental impact of health care activities, including methods for the measurement of these impacts. This literature is particularly rich on health care’s climate impact (e.g., (Reference Lenzen, Malik and Li12;Reference Braithwaite, Smith and Leask13)). Also, several authors have already outlined approaches for taking into account health care’s environmental impact in health care decisions (e.g., (Reference Walpole, Weeks and Shah14–Reference Toolan, Walpole and Shah16)), sometimes including quantitative measures that can be used on the same footing as conventional criteria like effectiveness and cost-effectiveness. In particular, an Incremental Carbon Footprint Effectiveness Ratio (ICFER) has been proposed, which relates the carbon dioxide emissions of a medical intervention to the quality-adjusted life years (QALYs) gained, just as the Incremental Cost Effectiveness Ratio (ICER) relates financial costs to QALYs gained (Reference Kindred, Shabrina and Zakiyah17).

Two criteria to assess climate impact

Greenhouse gas emissions have been more intensively documented than other environmental impacts of health care activities, and can be expressed in a single metric (CO₂ equivalents). We have, therefore, focused our proposals on the measurement of climate impact. Our specific recommendations for this new criterion have been summarized in the box, together with a simple example. Decisions on inclusion of interventions for reimbursement or in guidelines usually involve a comparison of two interventions, for example, a new one with an existing treatment. In order to compare the climate impact of these interventions, two measures are needed: (1) the difference in greenhouse gas emissions per patient, and (2) the difference in total greenhouse gas emissions for all patients receiving the intervention.

Measure (1), which we have labeled “incremental climate impact,” can be expressed as “greenhouse gas emissions per QALY” if the interventions to be compared are not equally effective. In this form, the measure resembles the ICFER proposed in the literature. It gives the health gain of a treatment a “climate price tag,” just like the ICER gives it a financial price tag. This allows decision makers to choose the alternative with the most favorable ratio between health gain and climate damage.

However, this first measure does not yet allow decision makers to judge the urgency of taking into account the climate impact of the intervention. For that, they also need to know the total greenhouse gas emissions for that intervention at the national level. This does not only depend on the greenhouse gas emissions per patient, but also on the total number of patients who will receive the intervention. The second measure that we propose, and that we have labeled “total climate impact,” is analogous to the criterion of “budget impact,” which is currently used in the Netherlands to assess the financial feasibility of reimbursing new expensive drugs. It can be compared with the greenhouse gas emissions of the entire Dutch health care system, and with the remaining “carbon budget” of the Dutch health care system. This “carbon budget” follows from the international agreements to limit global warming to 1.5 °C, which limit the total amount of CO₂ that may still be emitted. The larger the share of an intervention in the greenhouse gas emissions of the entire health care system, and the larger its burden on the remaining health care carbon budget, the more weight its climate impact should be given in reimbursement and guideline decisions. As the example in Box 1 shows, even a single intervention can have a large “total climate impact.”

Readers may note that, while the health effects of an intervention affect a number of individuals in a specific country (i.e., the Netherlands), the climate impact of the intervention will ultimately affect the whole world. This difference in scope may seem unusual, but it is not unlike the difference in scope inherent in an incremental cost-effectiveness ratio: while the health benefits of an intervention accrue to a specific group of people, the costs are usually borne by all tax- or premium-payers. This reflects the moral conviction that taking care of the sick is a collective responsibility. In the case of our proposed measures of climate impact, the difference in scope reflects the moral conviction that national health care systems are accountable for their worldwide environmental impacts.

It is currently impossible to specify quantitative norms for when an intervention’s climate impact is too large for reimbursement or inclusion in clinical guidelines, or to specify fixed rules for when a more climate-friendly alternative should be preferred. This even applies to the relatively simple situation in which two interventions are equally effective but have different climate impacts, because they may still differ in, for example, financial costs. Such norms or rules can only be specified after more experience has been built up with weighing climate impact against other criteria, and after the range of possible outcomes has been mapped.

We have therefore proposed to use these two criteria, alongside the existing criteria (e.g., effectiveness, cost-effectiveness, necessity, budget impact, …), in a deliberative decision-making process, by bringing them to the table of the relevant decision-making bodies. In the Dutch context, this would be the advisory committee for reimbursement decisions ( Advies Commissie Pakket ) and the various guideline committees of professional medical associations. These bodies have extensive experience in weighing the existing criteria, using forms of structured deliberation, but would need one or more additional experts in the field of environmental sustainability to be able to effectively handle the new criteria.

Next steps

Our approach has several limitations:

• - The most important is that it considers climate impact only and ignores other environmental impacts. This creates a risk of favoring interventions that do better on greenhouse gas emissions, but worse on other environmental impacts, such as biodiversity loss or environmental pollution (Reference Steenmeijer, Rodrigues, Zijp and Waaijers-van der Loop1). Think, for example, of two pharmaceuticals, one of which is associated with low greenhouse gas emissions but high toxicity when released in the environment, while the other is less toxic but has a larger climate impact. Unfortunately, it is not yet possible to bring other environmental impacts on board in a similarly straightforward and transparent way as climate impact. When making decisions on specific interventions, it should therefore always be carefully assessed whether other impacts than climate impact are likely, for example, by eliciting expert advice. If so, this information can be considered during the final deliberations, when all criteria are evaluated and weighed against each other, as outlined above.

• - Another limitation is that adding climate impact to the existing criteria creates a risk of “double counting.” For example, some of the environmental impacts of an intervention may already be included in the cost-effectiveness estimates (e.g., when the costs of the intervention include the costs of a tax on carbon emissions). It could therefore be argued that climate impact (and other environmental impacts) should be integrated into one of the existing criteria. This would not only avoid any “double counting” but would also reduce the need for subjectively weighing environmental impacts against the other criteria. However, this is currently not yet feasible, partly because there is currently no consensus on what monetary values should be attached to climate impacts (Reference Pizzol, Laurent and Sala19), but this is certainly an area for further study.

Although we believe that climate impact should urgently be considered in health care decision making, we also acknowledge that more work is necessary before these criteria can routinely be used. In addition to the issues mentioned above, important areas of further work include:

• - Measurement of greenhouse gas emissions has not yet been adequately standardized, for example, in terms of the boundaries of the required life cycle analyses (Reference Kouwenberg, Cohen and Hehenkamp18;Reference Pizzol, Laurent and Sala19). It is therefore important to use one of the existing protocols, such as ISO 14040/44, and to use the same approach for each of the interventions that are being compared. Whenever more specific standards become available, such as the recent standard for environmental life cycle assessments of pharmaceuticals (https://standardsdevelopment.bsigroup.com/projects/9025-12045), these can be used. Even then, outcomes should be carefully evaluated against their sensitivity to methodological variations.

• - It should also be assessed to what extent there is support among policy makers, patients, professionals, and citizens for exclusion of interventions from reimbursement or guidelines based on their climate impact. Surveys in the Dutch general population and among patients indicate that there is some, but limited support for such decisions (Reference Verhaar, Menting and Knottnerus20;Reference Verhaar, Knottnerus, Brabers and Wagner21). This may change when the rationale of these new criteria has been communicated more widely and when the potential consequences of taking climate impact into account have become more visible.

Based on our advisory report, the National Health Care Institute has decided to start using the new criteria on an experimental basis. During a three-year testing period, valuable experience will already be built up while the above-mentioned problems are tackled, both in the Netherlands (e.g., with the help of a dedicated research program (22)) and abroad (e.g., within the framework of the European Union initiative to harmonize Life Cycle Assessments (23)). It should be remembered that the introduction of “cost-effectiveness” as a criterion for health care decisions took approximately fifteen years in the Netherlands. Although that is a delay we cannot afford in the area of climate change, it does illustrate that new criteria cannot be implemented overnight.