There is an important distinction between a treatment being cost-effective and it being affordable for the NHS as illustrated by the example of tirzepatide. NICE has concluded that tirzepatide is cost-effective in appropriately selected patients because of the health gains it delivers through reductions in obesity-related disease and its complications. However, the overall budget impact is a separate question. When millions of people could potentially be eligible for treatment, even a cost-effective intervention can create major financial pressures for the NHS.
We are still at a relatively early stage of implementation, yet tirzepatide has already become one of the NHS's highest-cost medicines. If access expands in line with NICE guidance over the coming years, expenditure will increase substantially unless drug prices fall significantly, prescribing criteria change or treatment strategies evolve.
Another important issue is that we still have key unanswered questions about long-term use. We know that many people regain weight when treatment stops, suggesting that many patients will require long-term treatment. That has major implications for affordability, NHS workforce capacity and service planning. While future oral GLP-1 medicines and increased market competition may reduce acquisition costs, the overall financial commitment could still be considerable because of the very large numbers of eligible patients.
It is also important not to view obesity solely through the lens of medication. These drugs are valuable additions to our therapeutic options, but they do not address the underlying drivers of obesity. Unless we make much greater progress in tackling the obesogenic environment - including poor diets, the marketing and availability of unhealthy foods, physical inactivity, socioeconomic disadvantage and wider health inequalities - we risk creating a system in which increasing numbers of people require lifelong medication for a condition that could, at least in part, have been prevented.
There are also additional costs associated with prescribing these medicines that are sometimes overlooked. Patients need access to comprehensive weight management services, including dietary advice, behavioural support, physical activity programmes, monitoring of treatment response, management of side effects and support for maintaining weight loss. The success of these medicines depends not only on the prescription itself but also on investment in the wider clinical infrastructure needed to support patients.
From a broader NHS perspective, there are also opportunity costs. Every additional pound spent on obesity medicines is a pound that cannot be spent elsewhere in the health service. Policymakers therefore need to balance the considerable health benefits of these medicines against competing demands for finite NHS resources.
That said, we should also recognise their potential long-term benefits. If these medicines substantially reduce rates of type 2 diabetes, cardiovascular disease, osteoarthritis and other obesity-related conditions, they could reduce future demand on the NHS. The challenge is that the costs are immediate and highly visible, whereas many of the health and financial benefits will accrue over many years and are difficult to quantify.
Ultimately, the debate should not be framed as "drugs versus prevention". The NHS needs both. Effective pharmacological treatments should be available to people who are most likely to benefit from them, but they must be part of a comprehensive obesity strategy that places much greater emphasis on prevention, tackling the commercial and social determinants of obesity, and creating environments that make healthy choices easier. Unless we invest in prevention alongside treatment, demand for these medicines will continue to grow, making it increasingly difficult for the NHS to sustain this level of expenditure over the long term.
Some of these comments were used in an article published in the BMJ.
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