Background: Changes were made to the Australian guidelines for vitamin D testing in November 2014 which restricted the patients who could be tested and reimbursed under the Medical Benefits Schedule. A retrospective study was conducted to assess the impact of the changes.
Methods: Data from 588,021 cases tested for vitamin D over the period of 2014 to 2017 were obtained and the results in 149,808 cases tested before the change in guidelines were compared to 438,213 cases tested afterwards.
Results: The results showed an initial fall in requests took place after the introduction of changes, but request numbers had returned to pre-change levels by November 2016. Furthermore, following the intervention, there was a significant reduction in the number of cases of vitamin D deficiency (<50 nmol/L) detected after November 2014 (P < 0.001) with odds ratio (OR) calculations showing the strongest effect for the sub-cohort of 0-20 nmol/L (OR = 1.77). For patient vitamin D levels >71 nmol/L, the pattern of detection inverted with more cases of sufficiency being detected after the intervention than before (OR from 0.84 to 0.48, P <0.001).
Conclusions: The failure to show a sustained reduction in vitamin D testing is a common finding with demand management strategies to limit test requesting. More significant is the failure of the intervention to improve the detection of vitamin D deficiency. These failures highlight the need for better tools to manage test requesting including the use of audit and outcomes measurement to guide future interventions.
Keywords: Calcium; bone disorders; endocrinology.