Australian GPs Ordering More Imaging Tests Than Ever Before

July 25, 2014

General practitioners in Australia are increasingly ordering imaging tests, with an increase of 45 percent over the past decade.

There has been a 45 percent increase in the number of imaging studies ordered by general practitioners in Australia, according to a survey released by the University of Sydney.

Researchers from the university sought to determine how general practitioners were ordering imaging tests and if there were any changes since the most recently published report from 2001. Data obtained were based on the Bettering the Evaluation and Care of Health (BEACH) program of 9,802 general practitioners - more than 980,000 GP-patient encounter records - between 2002 and 2012. The BEACH program is a continuous, randomized national study of general practice activity in Australia.

The study periods were divided into Period 1, April 2002 to March 2005 (inclusive) and Period 2, April 2009 to March 2012 (inclusive). The factors examined were the number of physician/patient encounters, the number of problems managed during the encounters and the rate of tests ordered by the physician to manage the problems.

“Over time (from Period 1 to Period 2), there were statistically significant increases in almost all of these factors,” the authors wrote. “The only factor to remain steady was the number of tests ordered once the decision to test was made.”

 Period 1Period 2
Average number of GP encountersApproximately 23 million per yearApproximately 120 million per year
Problems managed by GPs during the encountersAverage of 149.1 per 100 encountersAverage of 157.6 per 100 encounters
Rate of imaging tests ordered8.7 per 100 encounters10.2 per 100 encounters

“Extrapolation of this result suggests an average 8.45 million imaging tests ordered by GPs per year in Period 1 and 12.23 million per year in Period 2, an increase of 44.7 percent, equating to approximately 3.78 million more orders per year over the three years in Period 2 than in the years of Period 1,” the authors noted.

The researchers found that the likelihood of ordering an imaging during the management of problems increased from 5.3 percent to 5.8 percent, while the average number of imaging tests ordered per 100 tested problems remained steady (111.0 per 100 tested problems in Period 1 and 112.1 in Period 2).

When looking at specific imaging modalities, the researchers found that general radiographs were ordered less frequently but those for ultrasounds, CTs and MRIs were ordered more often.

Annual orders:

 Period 1Period 2
Radiography32.7 orders per 1,000 clinical problems29.8 per 1,000 clinical problems
Ultrasound17.1 orders per 1,000 clinical problems23.5 orders per 1,000 clinical problems
CT5.9 orders per 1,000 clinical problems7.4 orders per 1,000 clinical problems
MRI0.3 orders per 1,000 clinical problems1.0 orders per 1,000 clinical problems

 

 

Common use:

 Common reasons for orders
General radiographyOsteoarthris, back problems, fractures, sprains, strains
UltrasoundPregnancy, abdominal pain, shoulder problems
CTBack
MRIBack problems, knee problems, osteoarthritis, sprains, strains, musculoskeletal injuries or problems

 

 

 

 

"Most imaging tests ordered by GPs comply with expert guidelines," lead author Dr. Helena Britt said in a release. "However, the study indicates that GPs are too quick to order imaging tests during their initial assessment of back problems. GPs are twice as likely to order an imaging test during the initial examination of new back-problems compared to follow-up consultations.”

There were four strong predictors of whether general practitioners would order imaging tests. These included:

• How many problems were presented at each encounter – each extra problem increased the probability of testing by 41 percent

• The type of medical problem – musculoskeletal, female genital issues, pregnancy and family planning issues

• Patient characteristics – females, those aged 45 and older, and new patients

• GP characteristics – women, GPs aged 35 to 44, those in solo practice and those in a practice co-located with an imaging service.