Sustainability in HTA
Beyond Rhetoric to Responsibility
Sustainability has become a mantra in Health Technology Assessment (HTA) circles, but it is rarely defined, and even less frequently implemented. A good example of this is the recent International Network of Agencies for HTA (INAHTA) White Paper entitled ‘Advancing Environmental Sustainability Through HTA’. The report uses the term sustainability rhetorically to convey ethical legitimacy, align HTA with climate policy and expand the scope of HTA from economic evaluation to environmental impact assessment. The language is largely promotional and consensus-oriented, avoiding confrontational or critical framings (e.g., there are no references to unsustainable practices by name). Perhaps this is appropriate for a network representing a coalition of 22 international HTA agencies, but for the reader the absence of critical reflection is frustrating.
Notably absent is any definition or operationalisation of sustainability. The concept is treated as self-evident, with little disaggregation (e.g., into environmental, financial, or social dimensions). Ultimately, the INAHTA White Paper uses sustainability as a boundary concept – normatively appealing and rhetorically versatile. While it functions to align HTA with contemporary ethical and policy imperatives, it would benefit from clearer definitional work and acknowledgment of the complexities involved in operationalising sustainability within HTA.
This rhetorical approach risks diluting the analytical precision of the term. Additionally, the aspirational tone may obscure the trade-offs or tensions that may emerge when integrating environmental sustainability into HTA frameworks. For this reason, I believe it is important to examine the concept of sustainability in more detail.
What are we really talking about?
As a starting point, it is useful to reference back to the most common concept of sustainability, the definition of ‘sustainable development’ from the 1980s.
Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs
— Our Common Future (Brundtland Report, 1987)
This definition foregrounds intergenerational equity and integrates economic, social, and environmental domains. By contrast, the HTA literature to date seems to attach sustainability to any framework that captures environmental impacts.
Towards a framework for defining sustainability in HTA
To be meaningful, HTA’s contribution to sustainability must be situated within a broader framework of how environmentally damaging human activity leads to dangerous climate change with consequent impact on global human health. This is what the figure below attempts to convey. The health calculator at the bottom of the figure illustrates how this impact of climate change on health can be positively impacted by mitigation efforts (such as substituting fossil fuels with renewable energy sources) and adaptation efforts (such as improving flood defences), while acknowledging the problem of ‘mal-adaptation’ (such as the increasing reliance on air-conditioning to combat rising temperatures) which has a negatively reinforcing effect.
While economic growth drives environmental degradation and damaging climate change, it also has a potentially huge impact on human health. As Hans Rosling argued, economic growth has been responsible for bringing vast swathes of the global population out of poverty with consequent rise in life-expectancy and the narrowing of (health) inequalities. This increase in life-expectancy in turn increases the potential for economic growth (hence the double ended arrow).
How does the health sector (and by implication HTA) interface with this framework? Well there is clearly a positive impact on health based on existing (and innovative new) technologies. But this comes at the cost of contributing to environmental damage (the health sector contributes approximately 5% of global greenhouse gas emissions). While of course the health sector is an important contributor to economic growth.
Can we leverage this framework for helping to define a concept of sustainability for the health sector / HTA? The health calculator in the figure gives a sense of the net-health effects of climate change accounting for the different sectors of the economy’s influence on climate change and health including the net influence of the health sector on health. Since in Figure 1 above, the health sector’s net impact on health is positive, one could argue that this is a workable definition of sustainability. However, if we look only at the net effect on the global population then we miss the nuances that are important in relation to the equitable distribution of that health, and the dynamics of where likely changes due to climate change are to come in the future.
Two equity dimensions are particularly salient in the context of the dangerous climate change debate—inequity between rich and poor countries—and inequity between the current and the next (and future) generation(s). This is illustrated in the second figure below that looks only at the net effect of the health sector on health.
What we see in Figure 2 is the same net-effect of health illustrated in Figure 1 but now split between rich countries and poor countries. The illustration suggests that rich countries have a greater proportional net-health impact than poor countries on the assumption that poorer countries will likely bear more of the ill-effects of dangerous climate change. But just as importantly, the figure contrasts the current generation (split between rich and poor countries) with the next generation (also split between rich and poor countries). Overall, the anticipated effects of dangerous climate change is that the overall situation will be worse in the next generation reducing the net impact on health. Most importantly however, there is the potential for compounding of the disadvantage such that is the poor countries in the next generation that could suffer most of the ill-effects of dangerous climate change with the potential that they could experience a negative net overall effect on health. This, I would argue, is the antithesis of sustainability, and this is what we need to be most concerned about.
From concept to calculation
Operationalising the framework requires dynamic modelling that embeds the health sector within the macro-economy. Computable general equilibrium (CGE) models with embedded health functions offer one promising path. These can help simulate how climate-driven shocks, policy interventions, and health system responses interact over time and across regions.
Concluding comments
The impacts of climate change are not distributed evenly. High-income countries consume far more resources per capita but often focus their HTA on marginal improvements to specialist care for their own populations. Meanwhile, low-income countries face the most severe consequences of climate instability—with far fewer resources to adapt. The INAHTA report makes only glancing reference to this reality and this is reflected more broadly in the HTA literature which often treats sustainability concerns in HTA as synonymous with capturing environmental impact of technologies.
Yet any serious discussion of sustainability in HTA must foreground global equity. Who bears the environmental cost of technology production? Who is left out of adaptation strategies? Whose baseline emissions are considered “normal”? HTA must not become a mechanism by which rich countries optimise their own carbon pathways while externalising environmental risk to poorer ones.
Sustainability as it relates to health economics and HTA, properly understood, is not just about environmental impact. If HTA is to serve future populations—not just current decision-makers—it must begin by asking who counts, who pays, and who is left behind.