Medicare restrictions fail to curb rising vitamin D testing rates

Doctors appear to be ignoring Medicare restrictions on ordering of vitamin D tests, which have failed to contain rising rates of unnecessary screening, according to new research.

Levels of vitamin D testing have continued to increase despite clinical criteria being added to MBS item descriptors in 2014 in an attempt to halt inappropriate and costly screening, Queensland researchers say.

In the decade prior to the introduction of Medicare restrictions, rates of vitamin D deficiency testing increased steeply from 0.4 to 36.5 tests per 1000 population, and the cost to Medicare rose from $1.1 million in 2000 to $151 million in 2012–13, they write in the MJA.

In November 2014, new MBS items were introduced with descriptors that limited testing to people with a history of osteomalacia or osteoporosis, elevated alkaline phosphatase levels, hyperparathyroidism, hypo- or hyper-calcaemia, hypophosphataemia, malabsorption, chronic renal failure, deeply pigmented skin or chronic and severe lack of sun exposure, or a diagnosis of vitamin D deficiency, and people who used medications that reduce 25-hydroxyvitamin D levels.

But researchers from the QIMR Berghofer Medical Research Institute, Brisbane say that Medicare figures show only a transient drop in vitamin D testing rates in 2015, and since then the rates have continued to increase, particularly for elderly people.

They note that the vitamin D testing rate increased by 34% between 2015 and 2019, from 119 to 159 tests per 1000 population and the cost to Medicare rebounded by 42%, from $73.7 million to $104.7 million a year.

The most marked increases were for people aged 85 years or over, for whom the 2019 testing rate (women, 447 tests per 1000 population; men, 364 tests per 1000 population) exceeded the 2012 levels.

Vitamin D testing rates for young people aged 0–25 years did not markedly change.

They say the findings show that education of practitioners, evidence-based guidelines and Medicare criteria have failed to contain the enthusiasm for vitamin D testing.

“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,” they write.

They add that vitamin D testing is costly ($30 per test) and unnecessary for the majority of people at risk of vitamin D deficiency, who could be treated without testing, with supplements  that cost only $2.25 per month.

“High quality research is needed to provide evidence for informing interventions that curb the use of low value tests in a health system that encourages a high volume of services, but not necessarily better value care,” they conclude.

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