Australia’s most common sexually transmitted infection, chlamydia, is unlikely to be eliminated by opportunistic testing in general practice, a landmark trial has revealed, with researchers recommending greater emphasis on improving chlamydia management.

Chlamydia is hard to control because many people are unaware they have it. If left untreated, it can cause serious infections of the uterus or fallopian tubes (pelvic inflammatory disease) in women that can lead to hospital admission in severe cases and can ultimately cause infertility.

This has led health departments in many high-income countries to recommend widespread testing for young adults.

Australian guidelines recommend “opportunistic” testing in general practice, which means testing any young person visiting their GP for any reason, whether or not they have symptoms, to reduce the number of people with chlamydia.

But in research published in The Lancet, a team led by the University of Melbourne has found that although GPs were able to increase testing among 16 to 29-year-olds by 150 per cent, it did not reduce the overall proportion contracting chlamydia.

The researchers argue that, rather than continue to focus on increasing chlamydia testing, GP resources would be better spent improving chlamydia management, which includes getting sexual partners tested and treated.

“While GPs should continue to test young men and women, we recommend focusing on better management of chlamydia once it’s been diagnosed as the best way to reduce the harm caused by chlamydia,” said Jane Hocking, lead researcher and sexual health epidemiologist.

“One of the biggest risk factors for developing pelvic inflammatory disease in women is getting re-infected with chlamydia. So we need to stop re-infection by getting sexual partners tested and treated, in order to reduce the number of cases that develop into pelvic inflammatory disease.”

The research found that increasing opportunistic chlamydia testing for 16 to 29-year-olds did reduce the incidence of severe pelvic inflammatory disease requiring hospital admission, but did not reduce milder cases in the community.

“But only a small number of chlamydia-associated pelvic inflammatory disease cases require hospitalisation. Most cases have mild symptoms only and remain undetected by a doctor,” Professor Hocking said. “If it’s detected early enough it can be managed relatively simply, reducing the risk of tubal damage and infertility. Ideally, it will be caught in general practice, and not end up with a hospitalisation.”

Professor Hocking and her team of collaborators from Monash University, University of New South Wales, Deakin University and University of Bern ran the trial from 2009-2015, involving 130 rural GP clinics in Victoria, New South Wales, Queensland and South Australia, over 1200 GPs and more than 90 000 people aged 16-29. It is the world’s largest and most comprehensive trial of opportunistic chlamydia testing in primary care.

The trial included several rounds of annual testing and measured the multiple biological outcomes of chlamydia prevalence, pelvic inflammatory disease in women and epididymitis in men (an inflammation in the testes, which can be caused by chlamydia infection).

“Ultimately, the best way to use our resources, and GPs’ limited time, is to focus on preventing the potentially devastating outcomes for women who contract pelvic inflammatory disease,” she said.