Vitamin D deficiency testing on the climb again

The number of tests for vitamin D deficiency is on the rise again despite measures taken in late 2014 to restrict testing to people at particular risk of vitamin D deficiency, according to the authors of a Perspective published online today by the Medical Journal of Australia.

The number of tests for vitamin D deficiency in Australia rose steeply between 2000 and 2011, from 0.4 to 36.5 tests per 1000 population; the cost to Medicare increased from $1.1 million in 2000 to $95.6 million in 2010, and peaked at $151 million in 2012–13. Consequently, the Medical Benefits Schedule (MBS) items for testing (66608, 66609) were replaced in November 2014 by new items (66833–66837).

"The immediate effect of the new criteria was that the rate of vitamin D tests was 47% lower during 2014–16 than during 2013–14," wrote the researchers, led by Professor Rachel Neale, Group Leader of Cancer Aetiology and Prevention at QIMR Berghofer Medical Research Institute.

"Medicare data indicate that the testing rate has since increased, by 34% between 2015 and 2019, from 119 to 159 tests per 1000 population, and the cost to Medicare rose 42%, from $73.7 million to $104.7 million.

"The testing rate increased in all states; the rate for women increased by 30% (from 164 to 214 tests per 1000 population), and for men by 40% (from 74 to 105 tests per 1000 population). The most marked increases were for people aged 85 years or more, for whom the 2019 testing rate exceeded the 2012 levels. Testing rates for people aged 0–25 years did not markedly change between 2015 and 2019.

"The marked overall increase in testing since 2015 is not explained by changes in demographic or clinical factors, suggesting that at least some screening is unnecessary and that ordering doctors are either unaware of or do not support the new MBS vitamin D testing criteria," Neale and colleagues wrote.

"Evidence-based guidelines and MBS policy, accompanied by education and audit activities, have failed to contain the level of vitamin D testing.

"Further, people who are socio-economically disadvantaged or at particular risk of vitamin D deficiency, including Indigenous Australians, are still tested less frequently than other Australians."

The authors concluded that people at clear risk of vitamin D deficiency could be treated without testing, especially as the cost of supplementation—$2.25 per month—is only a fraction of the cost of testing ($30.05).

"High quality research is needed to provide evidence for informing interventions to curb the use of low value tests in a health system that encourages a high volume of services, but not necessarily better value care," wrote Neale and colleagues.