Vitamin D testing patterns among general practitioners in a major Victorian primary health care service.

Objective: To examine 25(OH)D testing patterns and frequency among general practitioners in a major community health service.

Method: A clinical audit of patient records at a community health centre in Melbourne was undertaken. Patients aged 18 years and above were included. Univariate and multivariate logistic regression was used to examine the association between vitamin D testing and socio-demographic characteristics while Poisson regression was used for the frequency of testing.

Results: There were 1,217 patients tested for serum 25(OH)D. The community health centre was served by 12 general practitioners and an infectious disease specialist. The odds of vitamin D testing showed a positive, albeit weak, association with age (OR 1.01, 95%CI 1.00-1.02, p<0.05), were higher among females than males (OR 1.42, 95%CI 1.18-1.70, p<0.05) and higher among migrants compared to non-migrants (OR 2.57, 95%CI 2.14-3.09, p<0.05). The frequency of testing was also higher among females than males (IRR 1.17, 95%CI 1.07-1.28, p<0.05) and higher among migrants than non-migrants (IRR 1.19, 95%CI 1.08-1.31, p<0.05).

Conclusion: Advancing age, being female and being a migrant were associated with an increased likelihood of vitamin D testing.

Implications: Development of evidence-based policies and guidelines are needed to manage over-testing of vitamin D in Australia. Studies that include health services from different areas are required to understand vitamin D testing patterns among the general practitioners.