Researchers have identified several factors that can predict which children with asthma are at high-risk of an asthma attack.

Presenting the findings at the British Thoracic Society Winter Meeting in London last week the At-Risk Child with Asthma group said the factors could easily be used in clinical practice.

Their systematic review of the literature  looked at risk factors in children aged five to 12. They then used an expert panel to identify factors that “greatly, moderately, slightly” or did not increase risk of asthma attacks.

An expert panel identified factors that “greatly, moderately, slightly” or did not increase the risk of asthma attacks.

Presenting the findings to delegates Hilary Pinnock, professor of primary care respiratory medicine at Edinburgh University, explained that the group was unable to carry out a meta-analysis of the results from 69 papers because of heterogeneity. Instead, the expert panel used studies’ odds ratios to ascertain the effect sizes of 32 candidate factors.

They found mostly cohort studies, 80% of them from the US.

Factors found to “greatly” increase the chances of an asthma attack were:

• previous asthma attack
• persistent asthma symptoms
• poor access to care (in a US setting).

“Moderate” risk factors were:

• suboptimal medications (with a low controller/total medicine ratio)
• comorbid atopy
• African American ethnicity (in a US setting)
• Vitamin D deficiency

“The picture that emerges is that we are looking for a child who has had previous attacks, who has persistent symptoms and is on a suboptimal medication regime,” said Professor Pinnock. “This is something that could be used tomorrow in clinical practice.”

She warned that factors such as poverty and poor access to care may not be directly translatable to non-US populations.

However, she said some factors did not provide sufficient information to assess risk sufficiently, or were too variable.

These included FeNO testing, currently recommended in the NICE asthma guidelines. In addition, some measures were confounded by severity – for example, children using a nebuliser were at higher risk of attack, but because a nebuliser was prescribed only for more severe asthma.