No association between subnormal serum vitamin B12 and anemia in older nursing home patients
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Key summary points
To investigate the association between different clinical parameters, particularly subnormal serum vitamin B12 and anemia, in older nursing home patients.
No association was observed between subnormal B12 and anemia, while strong associations were observed between renal failure, inflammation/infection, iron deficiency and anemia.
Vitamin B12 probably plays a limited role in the etiology and treatment of mild/moderate anemia in older patients, living in a Western society, and not suffering from pernicious anemia.
Since evidence of an association between vitamin B12 (B12) deficiency and anemia in older people is limited and inconclusive, we wanted to investigate this association in old, frail nursing home patients.
The study includes patients admitted to short-term, post-acute care (n = 765) and residents in long-term care (LTC) (n = 1665), in the municipality of Bergen. Anemia was defined according to the WHO criteria: Hb < 13 g/dL in men and < 12 g/dL in women, and as Hb < 11 g/dL, in both sex (moderate/severe anemia). The presence of anemia was analyzed in patients with subnormal (< 250 pmol/L), normal (250–650 pmol/L) and high (> 650 pmol/L) B12, and the association between anemia and clinical parameters, and including B12, was analyzed using logistic regression models. The use of B12 supplementation was investigated in the LTC patients.
Mean age of the 2430 patients was 86 ± 7 years. WHO-defined anemia was seen in 1023 (42%), and moderate/severe anemia in 384 (16%) of the patients. In multiple logistic regression analyses, we found no statistically significant associations of subnormal B12 with WHO-defined anemia or moderate/severe anemia. Renal insufficiency, iron deficiency and CRP > 10 mg/L were significantly associated with both types of anemia, (p < 0.001). Among the LTC residents, 405 (24%) received B12 supplements, 112 (7%) of them had elevated B12 > 650 pmol/L.
In older nursing home patients, no association was observed between subnormal B12 and anemia. Older patients in Western societies with mild/moderate anemia should not be treated with B12 supplements without further investigation.
KeywordsOlder Nursing home Anemia Vitamin B12 Supplementation
JFA is the initiator, project leader and the first author of the manuscript. ALBM is responsible for the biochemical analyses and has contributed in the analyses of data. RMN has been supervising the statistical work. AHR has taken part in the initiation of the study and supervising the ongoing research. MR, EE and KK have been responsible for developing, managing and retrieving adequate data from the electronic database of the LTC patients. All authors have contributed to the manuscript preparation and critical review of the manuscript. All authors read and approved the final manuscript and agree to be accountable for all aspect of the work.
Part of this study, concerning the PAC patients, was funded by Western Norway Regional Health Authority (Grant number 911926). The funding source had no role in the study design, in the collection, analysis and interpretation of data, in the writing of the report or in the decision to submit the article for publication.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
The study protocol of the PAC patients that were enrolled in a prospective study was approved by the Regional Committees for Medical and Health Research Ethics (REC), (2011/1893/REK Vest). For the LTC patients, retrieval of anonymous data (blood samples, age and information on B12 supplements) from electronic patient records for quality surveillance purposes, was approved and performed as regularly by Department of Nursing Home Medicine in the Municipality of Bergen.
Written informed consent was obtained from the PAC patients, and in case of moderate/major cognitive impairment leading to a decline in judgement, from their closest proxy. For the LTC patients, no written informed consent was asked for since the limited dataset was truly anonymous, could not stigmatize any group, and blood sampling were performed routinely as part of half-yearly drug surveillance demanded by national authorities. This is in accordance with national legislation on anonymous data handling (https://oslo-universitetssykehus.no/personvern/hva-er-forskjellen-pa-avidentifisert-og-anonymt). All patients, (or in the majority of cases their nearest proxy) had accepted that blood tests were taken to get information that would aid a critical medication review.
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