Factors correlating to the propensity of general practitioners to substitute borderline vitamin B12 deficiency

Objective: This study aims to identify factors which correlate to the propensity of general practitioners (GPs) to prescribe supplementation for borderline vitamin B12 deficiency. Design: Cross-sectional surveys were distributed in person. Setting: Conferences held in Cairns, Palm Cove Beach, Mt Isa; educational meetings in Atherton; and meetings with individual general practices within the Cairns and Hinterland region. All located in Queensland, Australia. Subjects: 128 practicing GP specialists and registrars (practitioners in training). Main outcome measures: Responses to the Likert scale statements with its five options scaling from ‘strongly disagree’ to ‘strongly agree’ were recoded to have binary outcomes for analysis. Results: A survey response rate of 89% was achieved. Participants who felt patient demands influence the management of borderline vitamin B12 deficiency were more likely to prescribe supplementation (OR 2.4, p = 0.037). Participants who perceived an overuse of vitamin B12 were less likely to prescribe B12 (OR 0.39, p = 0.019). Participants who often saw patients with vitamin B12 deficiency were less likely to request for the complementary biomarkers plasma methylmalonic acid or total homocysteine (OR 0.41, p = 0.045). Conclusions: KEY POINTS: General practitioners hold different thresholds for commencing supplementation in cases of borderline vitamin B12 deficiency. Participants from Australia were asked to fill out a cross-sectional survey to explore factors which correlate with the propensity to prescribe in clinical practice. Our study identified that patient demands and a practitioner’s perception of whether there is an overuse of vitamin B12 in the community influenced the propensity to treat for deficiency. The results give insight into reasons for initiating supplementation, and will help inform general practitioners on their current management.