Anello: Vitamin B12 injections for the elderly [CMAJ

Vitamin B₁₂ injections for the elderly

CMAJ 2000;162:1274

See response from: C.G. van Walraven, C.D. Naylor

In their article on the use of vitamin B₁₂ injections for elderly patients by primary care practitioners in Ontario, Carl van Walraven and David Naylor acknowledge that a major problem with their study is that overutilization is identified but underutilization is not [Evidence].¹ Patients with cobalamin deficiency, but with normal serum vitamin B₁₂ levels according to current definitions, may present with neuropsychiatric symptoms ranging from innocuous paresthesias and fatigue to dementia and psychosis.^2,3 Practitioners cognizant of the serious morbidity possible with cobalamin deficiency might opt to risk overutilizing this safe, inexpensive therapy: serum vitamin B₁₂ determinations cost the system approximately $20 and vitamin B₁₂ therapy is relatively inexpensive. Although functional biochemical testing of methylmalonic acid and homocysteine levels prior to commencing therapy would reduce overutilization (and underutilization), these tests, which cost $160 in total, are currently not covered by the Ontario Health Insurance Plan. This is an unacceptable financial burden for the elderly population.

Metabolic evidence from the Framingham study showed that cobalamin deficiency is present in 1 in 8 or 1 in 5 elderly people.⁴ Yao and colleagues suggested that serum cobalamin screening be done for every person aged 65 and older and that the normal range be increased to 250–300 pg/mL.⁵ Screening for cobalamin deficiency at our southwestern Ontario community health clinic yielded a 20% prevalence in the elderly.

Dementia and impaired cognitive functioning may result from vitamin B₁₂ deficiency, although most of the evidence is from observational studies.^4,5,6 The costs of misdiagnosing a potentially reversible dementia resulting from cobalamin deficiency may justify erring on the side of overutilization until more studies are done on the utility of vitamin B₁₂ treatment. Fewer interventions in primary care are as simple, safe and satisfying to both practitioner and patient as the detection and appropriate treatment of symptomatic cobalamin deficiency.

Francesco Anello
Family physician
Woolwich Community Health Centre
St. Jacobs, Ont.

Send a letter to the editor
Envoyez une lettre à la rédaction

References

van Walraven CG, Naylor CD. Use of vitamin B₁₂ injections among elderly patients by primary care practitioners in Ontario. CMAJ 1999;161(2):146-9. [MEDLINE]
Pennypacker L, Allen R, Kelly J, Matthews LM, Grigsby J, Kaye K, et al. High prevalence of cobalamin deficiency in elderly outpatients. J Am Geriatr Soc 1992;40:1197-204. [MEDLINE]
Healton EB, Savage DG, Brust CM, Garrett TJ, Lindenbaum J. Neurologic aspects of cobalamin deficiency. Medicine (Baltimore) 1991;70:229-45. [MEDLINE]
Lindenbaum J, Rosenberg I, Wilson P, Stabler S, Allen R. Prevalence of cobalamin deficiency in the Framingham elderly population. Am J Clin Nutr 1994;60:2-11. [MEDLINE]
Yao Y, Yao SL, Yao SS, Yao G, Lou W. Prevalence of vitamin B₁₂ deficiency among geriatric outpatients. J Fam Pract 1992;35:524-8. [MEDLINE]
Bell IR, Edman JS, Marby DW, Satlin A, Dreier T, Liptzin B, et al. Vitamin B₁₂ and folate status in acute geropsychiatric patients: affective and cognitive characteristics of a vitamin nondeficient population. Biol Psychiatry 1990;27:125-37. [MEDLINE]