{
  "abstract": "Pernicious Anaemia is an autoimmune-mediated disorder of vitamin B12 absorption, managed using fixed-interval vitamin B12 replacement regimens. Despite treatment, many patients report persistent or recurrent symptoms, suggesting substantial inter-individual variability in treatment response. More tailored approaches may therefore be needed to reduce symptom burden and improve quality of life. This prospective observational study used high-frequency longitudinal digital symptom monitoring to characterise symptom dynamics and heterogeneity in treatment response. UK adults with pernicious anaemia, recruited via the Pernicious Anaemia Society, self-reported daily symptoms (severity 0-10) and vitamin B12 treatments over three months. Analyses quantified within- and between-person variability, injection-aligned symptom response kinetics, and differences in treatment response by injection frequency. Sixty-eight participants were included in the longitudinal analyses, providing >5,100 person-days of symptom data over a mean of 76 days (SD 28). Most symptom variance was attributable to stable between-person differences (ICC range, 0.58-0.80), indicating the persistence of individual symptom phenotypes. Vitamin B12 injections were followed by rapid symptom improvement, although magnitude and timing varied markedly by symptom domain. Seventy-one percent of participants were classified as responders for composite symptom burden (median 4.65 to 2.36; p<0.001), while 29% showed no meaningful multisystem improvement (3.59 to 3.58; p=0.63). Cognitive symptoms improved earliest, typically within 24-72 hours; fatigue and pain responses peaked at 3-5 days, and neuro-sensory symptoms at 4-6 days. Responses clustered within individuals, indicating distinct responder phenotypes. Overall symptom burden improved most among participants receiving monthly injections, whereas those injecting weekly or more often had higher pre-injection burden and smaller improvements. These findings suggest that fixed-interval vitamin B12 replacement may not adequately reflect individual variation in symptom recurrence and treatment response. High-frequency digital symptom monitoring may provide a practical framework for characterising these patterns and for evaluating more individualised, symptom-guided vitamin B12 management.",
  "abstract_shown": true,
  "affiliations": [
    "University College London"
  ],
  "article_type": "PUBLISHAHEADOFPRINT",
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "A. Thain"
    },
    {
      "name": "K. Hart"
    },
    {
      "name": "K. Burchell"
    },
    {
      "name": "P. Visser"
    },
    {
      "name": "K. R. Ahmadi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/aww5826ar7wkp.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.11.03.26367157",
  "fulltext_url": "https://www.medrxiv.org/content/10.64898/2026.11.03.26367157v1.full",
  "id": "aww5826ar7wkp",
  "issns": [],
  "landing_url": "https://www.medrxiv.org/content/10.64898/2026.11.03.26367157v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "medrxiv",
      "gastroenterology"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://www.medrxiv.org/content/10.64898/2026.11.03.26367157v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-03",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/aww5826ar7wkp.ris",
  "sources": [
    {
      "first_seen": "2026-11-05T00:20:40Z",
      "native_id": "10.64898/2026.11.03.26367157",
      "source": "medrxiv",
      "url": "https://www.medrxiv.org/content/10.64898/2026.11.03.26367157v1"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "medrxiv:gastroenterology",
      "subfield": "general"
    }
  ],
  "title": "Symptom variability and treatment response in pernicious anaemia: a longitudinal daily symptom tracking study",
  "title_text": "Symptom variability and treatment response in pernicious anaemia: a longitudinal daily symptom tracking study",
  "type": "preprint",
  "updated_at": "2026-11-06T00:20:55Z",
  "url": "https://research.draconitic.com/paper/aww5826ar7wkp",
  "venue": "medRxiv",
  "versions": []
}