Chlamydia screening programme may do more harm than good

By Emma Wilkinson

The Government's national chlamydia screening programme is not only unsupported by evidence but may actually do more harm than good, a wide-ranging analysis warns.

The systematic review found no randomised trials showing any benefit of opportunistic screening in under 25s except in women undergoing termination of pregnancy.

Researchers also found trial quality was generally poor, that there were no trials of the effect of more than one screening round and none examining potential adverse effects.

Study leader Dr Nicola Low, who was a member of the NHS-funded Chlamydia Screening Studies (ClaSS) Project Group, said decisions on introducing screening in the UK had been made without a full appraisal of the evidence – even though it was available at the time.

She told Pulse: ‘Screening programmes are extremely popular and everyone always thinks they're going to be beneficial when they rarely are. There was an overwhelming desire to do something and it was thought screening would be the right way to go about it.‘

Dr Low, reader in epidemiology and public health at the University of Bern in Switzerland, said trials were now needed to assess the best way to carry out and monitor screening, to prove it causes more good than harm and is not a waste of money.

‘We think the evidence is also not strong enough to say a systematic programme would work,' she said. ‘GPs should be aware of the limitations of the evidence on screening.'

Dr Sarah Jarvis, a GP in Hammersmith, west London, and RCGP spokesperson on women's health said it would not be the first time the Government had gone ahead with a strategy before the studies had been done. ‘I'm not for a second saying it wouldn't be valuable but the evidence we have so far is not enough.

‘It intuitively feels as though chlamydia screening is going to be a good thing. All we can say is it's not something which is going to give false negatives or false positives and it's a completely treatable condition.'

But Dr Richard Ma, a GP in Islington, north London, and member of the National Chlamydia Advisory Group, defended the decision to go ahead with a screening programme. He told Pulse: ‘Pilots were done, which showed screening was acceptable. Over a million people have now been screened and one in 10 was found to have chlamydia.'

- Of six systematic reviews, five randomised trials, one non-randomised comparative study and one time trend study, quality was generally poor, and methodological weaknesses could have biased all results
- Trials of opportunistic chlamydia screening have only been conducted in women undergoing surgical termination of pregnancy
- There was no evidence for the effectiveness of opportunistic screening in any other population, of multiple rounds of any screening approach or about the harms of chlamydia screening

Source: International Journal of Epidemiology 2008 5 December early online publication