While the guideline has several strengths, the proposal to replace the term ‘pernicious anaemia’ with ‘autoimmune gastritis’ is, in our opinion, a notable limitation. PA is considered to develop in advanced stages of autoimmune gastritis (AIG) rather than being entirely synonymous with it [6]. It is important to acknowledge that PA and AIG represent different stages of the same disease continuum. Autoimmune gastritis, characterised by advanced atrophy of the gastric oxyntic mucosa with a spared antrum, forms the pathological basis for PA. However, PA specifically refers to the clinical manifestation associated with IF deficiency and subsequent B12 malabsorption. Therefore, these conditions should not be referred to as identical entities but recognised as distinct stages within the natural history of the same disease. This change could exacerbate current confusion and add further uncertainty regarding the diagnosis and management of PA. The guidelines state, “However, pernicious anaemia in its true sense (that is, life-threatening anaemia) is now extremely rare because of developments in testing and treatment for, and greater awareness of, vitamin B12deficiency.”

In one sense, this statement is correct: the term ‘pernicious anaemia,’ when taken literally, implies a severe, life-threatening form of anaemia, which is uncommon in modern practice due to improvements in testing and treatment, such severe manifestations are typically prevented, as the condition is more likely to be diagnosed earlier or treated with B12. However, changing the name overlooks the broader clinical context of PA, which is not just an issue of anaemia but rather a condition characterised by the autoimmune-mediated destruction of parietal cells leading to IF deficiency and lifelong B12 malabsorption [1]. Three other points warrant mentioning. First, there is also a separate autoimmune-mediated attack on IF that will lead to PA. Second, not all AIG diagnoses translate to PA. PA occurs in only about 15–20% of AIG patients, highlighting the inaccuracy of using AIG as a substitute for PA [7, 8]. The life-course of PA development has not been studied, but there is sufficient information to highlight that the timelines are highly varied among patients. For instance, some individuals may develop PA as early as 1 year after the onset of AIG, while others may not progress to PA until 15 or more years after AIG onset [9]. Thus, whilst PA is acknowledged as a consequence of AIG, conflating the two terms risks oversimplifying the disease process and ignoring the clinical specificity of PA as an advanced manifestation. Third, over 50% of individuals with symptomatic B deficiency test negative for IF or parietal cell auto-antibodies, and the true prevalence of AIG in the UK is not known, as individuals with B deficiency rarely undergo endoscopy.

Whilst renaming PA as AIG can add confusion and uncertainty, the name PA has its own shortcomings, which is perhaps why NICE proposed to change it. The term ‘pernicious anaemia’ suggests that anaemia is a defining characteristic of the disease. However, anaemia is present in only 15–20% of PA diagnoses [2, 10]. Practitioners unfamiliar with PA are commonly misled by the term ‘anaemia’, as all ICD-10 (D51.0-9) codes for B deficiency incorrectly include the term anaemia. The term ‘pernicious’ is also an anachronism, predating the 1948 discovery of B as an effective treatment. It was first coined by Anton Biermer in 1871 to describe the fatal anaemia cases seen prior to the discovery of effective treatments. It is important to note that even though anaemia occurs in a minority of PA patients, this represents an important subgroup of patients that requires a different management approach. The current guidelines do not address how to specifically diagnose and manage this subgroup of patients, representing a significant gap in knowledge and warranting further research.

The definition and our understanding of the condition has evolved significantly since Biermer’s original description. We now know that PA often presents with predominantly neurological symptoms [3, 11]. Therefore, if a name change is warranted, it should be one that better reflects the current clinical presentation of the disease.

The persistent use of the term ‘pernicious anaemia’ in both clinical practice (primary, secondary and tertiary care) and state-of-the-art research highlights a disconnect between these guidelines and current clinical practice. It is important to highlight that the adoption of new and more appropriate terminology would require universal acceptance by clinicians, carers and patients who would have lived with the name PA for most of their lives. While changing established medical terminology may take decades—potentially one to two generations of doctors—before it is fully adopted in clinical language, emphasising that such a change, if it were to happen, would be gradual and require effective dissemination.

However, a name change could offer significant advantages by reflecting the current understanding of PA and encouraging clinicians to investigate neurological symptoms associated with PA [11]. This would be achieved through a concerted effort to educate doctors by incorporating this knowledge into the curriculum, which will dispel misconceptions commonly ascribed to PA patients by doctors and promote a deeper understanding of PA’s complexity.