Low cobalamin (vitamin B12) levels in multiple myeloma: a retrospective study.

BACKGROUND In patients with multiple myeloma a variety of metabolic events may occur. One of these are changes in the serum cobalamin (vitamin B12) concentration. Elevated as well as decreased serum cobalamin levels have been reported. The prevalence and clinical consequences of low cobalamin levels are largely unknown. OBJECTIVE To investigate the prevalence of low serum cobalamin levels in patients with multiple myeloma and to describe the clinical features, haematological parameters and outcome in patients with multiple myeloma with low and normal serum cobalamin levels. METHODS A retrospective study was conducted in the Deaconess Hospital in Eindhoven. Thirty-two patients were identified who fulfilled the diagnostic criteria for multiple myeloma and had at least one serum cobalamin level tested during the diagnostic or treatment period. A number of clinical characteristics, haematological parameters and outcome were scored. RESULTS Twenty-one (66%) patients had a normal serum cobalamin level, nine (28%) patients had a low one and two (6%) patients had an elevated serum cobalamin level. Between the group with a normal and a low serum cobalamin level there were no differences in patients characteristics such as sex and age, tumour characteristics such as the type of paraprotein, tumour load or tumour stage nor in haematological parameters such as haemoglobin level, mean corpuscular volume and megaloblastic changes in the bone marrow. The median survival was not statistically different between both groups.