RESULTS
Characteristics of patients. Eighteen cobalamin-deficient
patients were randomized to oral cyanocobalamin (Tables 1 and
2) and 15 to intramuscular treatment (Tables 3 and 4). A
majority in both groups were elderly women. All were white
except for 1 Latina patient. All but 1 or 2 patients in each group
were outpatients and most were not anemic. In 1 patient (no. 4),
the serum creatinine was increased (1.7 mg/dL). In 2 anemic
patients in the parenteral group (Table 3), iron deficiency
appeared to contribute to the anemia. The erythrocyte mean cell
volume (MCV) was elevated (.100 fL) in 7 and 8 patients,
respectively, in the 2 groups. Four patients in each group had
mild to moderate neurologic symptoms consistent with cobalamin
deficiency.
All patients had a low serum cobalamin; 2 in each group had
a decreased serum folate (Tables 2 and 4). Serum methylmalonic
acid was greater than 3 SD above the mean in normal
controls in all except no. 33 in the parenteral group. Serum total
homocysteine was greater than 3 SD above the normal mean in
10 and 12 patients, respectively, in the oral and parenteral
groups. The 2 groups did not differ significantly in mean age,
pretreatment hematocrit, MCV, serum cobalamin, folate, methylmalonic
acid, or total homocysteine.