SUBDIAGNÓSTICO DE LA DEFICIENCIA DE VITAMINA B12 EN ATENCIÓN PRIMARIA DE SALUD: CÓMO LOS CRITERIOS DIAGNÓSTICOS DISTORSIONAN LAS ESTIMACIONES DE PREVALENCIA — UNA REVISIÓN SISTEMÁTICA DE ESTUDIOS OBSERVACIONALES
Resumen
Vitamin B12 deficiency is frequent and underdiagnosed among adults and older adults in primary health care, linked to hematological, neurological, and neuropsychiatric outcomes. Nonspecific presentation and variable diagnostic criteria contribute to heterogeneous prevalence estimates and delayed identification. Objective: To analyze the prevalence and underdiagnosis of vitamin B12 deficiency in adults in primary care between 2020 and 2025. Methods: This integrative review followed the PRISMA 2020 checklist. Searches were conducted in PubMed and LILACS using descriptors and free terms related to vitamin B12, primary care, prevalence, and underdiagnosis. Observational studies with adults ≥18 years were included. After identification, screening, eligibility, and inclusion, 26 studies composed the final sample, although methodological heterogeneity and scarcity of national studies limited comparisons. Results: Prevalence ranged from <1% to >40% according to population, age, and criteria. When subclinical or borderline states were considered, combined prevalence exceeded 50% in several settings. A consistent increase with aging was observed, associated with restrictive diets, food insecurity, and chronic metformin use. Evidence showed substantial underdiagnosis due to nonspecific symptoms, low clinical suspicion, and reliance mainly on total serum vitamin B12. Conclusion: Vitamin B12 deficiency is frequent and underdiagnosed in primary care, especially among older adults, reinforcing the need for systematic screening, early diagnosis, and evidence-based management. Standardizing markers such as methylmalonic acid and homocysteine may improve diagnostic accuracy. Training professionals to recognize this reversible condition can reduce neurological and cognitive complications. Brazilian studies are needed to strengthen locally applicable evidence for practice.
Biografía del autor/a
Residente 2 de Medicina da Família e Comunidade – FAMENE, João Pessoa - PB, Brasil.
Médica em Medicina da Família e Comunidade – FAMENE, João Pessoa - PB, Brasil.
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