Variables. Main outcome variable: Cobalamin level standardization (yes/no). Secondary outcome variables: Adverse events. Adherence measurement of treatment. Health related quality of life questionnaire (Euroqol-5D). Satisfaction and preferences. Other variables: Gender. Age. Live alone. Vegetarian diet. Alcohols consume. Clinic Variables (symptoms and physical examination) and blood parameters. Drugs consume.~Causes of all losses and withdrawals. Number of patients (age and gender) who declined to participate.~All data (excluding patient identification data) will be record in an electronic database.~Intervention group: oral Optovite® B12 1000 gammas. Control group: idem intramuscular.~Analysis: Descriptive analysis (screening phase). Baseline comparison of the two intervention groups. Effect of cobalamin (main outcome variable). Security. Quality of life. Adherence measurement of treatment.
Objective: To determine the effectiveness of oral versus intramuscular Cobalamin (vitamin B12) by restore cobalamin parameter in blood at 8, 26 and 52 weeks in ≥ 65 aged patients with Cobalamin Deficiency.~Design: Noninferiority randomised controlled trial, pragmatic and multi-center in the primary healthcare setting (Madrid Region).~Participants: ≥ 65 aged patients with Cobalamin Deficiency. Patients give inform consent. Number of patients: 320 (160 each arm). Assignment: randomized simple (automatic system).~Variables. Main outcome variable: Cobalamin level standardization (yes/no). Secondary outcome variables: Adverse events. Adherence measurement of treatment. Health related quality of life questionnaire (Euroqol-5D). Satisfaction and preferences. Other variables: Gender. Age. Live alone. Vegetarian diet. Alcohols consume. Clinic Variables (symptoms and physical examination) and blood parameters. Drugs consume.~Causes of all losses and withdrawals. Number of patients (age and gender) who declined to participate.~All data (excluding patient identification data) will be record in an electronic database.~Intervention group: oral Optovite® B12 1000 gammas. Control group: idem intramuscular.~Analysis: Descriptive analysis (screening phase). Baseline comparison of the two intervention groups. Effect of cobalamin (main outcome variable). Security. Quality of life. Adherence measurement of treatment.