Evidence-based decisions around screening are vital says research
National recommendations on whether to screen newborn babies for rare conditions do not always assess the evidence on the key benefits and harms of screening, according to researchers.
The warning was made by researchers at the University of Warwick in a study published by the BMJ.
Decisions about which conditions to screen for vary widely between countries, despite similar populations and healthcare systems, said the paper. Effective screening programmes can save lives, whereas ineffective programmes can do more harm than good.
Reasons for the differences are unclear, but it has been suggested that the evidence review process used to generate policy – in particular the use of systematic reviews – may play a role.
To explore this further, a team of researchers led by Dr Sian Taylor-Phillips associate professor at Warwick Medical School, assessed whether use of a systematic review affects national decisions on whether to screen for a range of conditions using the newborn blood spot test, which is offered to every baby to detect rare but serious health conditions.
Their analysis included 93 reports that assessed 104 conditions across 14 countries, giving a total of 276 recommendations.
Screening was favoured in 159 (58%) recommendations, not favoured in 98 (36%), and not recommended either way in 19 (7%).
Only 60 (22%) of the recommendations were based on evidence from a systematic review. Use of a systematic review was associated with a reduced probability of screening being recommended (38% vs 63%).
Evidence for test accuracy was not considered in 115 (42%) of recommendations, while evidence around the benefits of early detection and the potential harm of over diagnosis were not considered in 83 (30%) and 211 (76%) of recommendations, respectively.
Dr Sian Taylor-Philips said: ‘This study shows that many national policy decisions about whether to screen for conditions are being made without systematically reviewing the evidence.
‘Yet it remains essential to make evidence-based policy decisions because once screening programmes are started they are difficult to stop.’
She called for further research to understand why policy makers do not employ systematic review methods in their evaluations of evidence.
Read the full paper here.