Doubts over lung function tests as basis for prevention
Lung tests fail to spot COPD risk
By Daniel Cressey
Testing lung function is not a valid way of determining if COPD patients need preventive treatment, a new study concludes.
The researchers called for guidance to change after finding lung function tests failed to predict a patient's risk of exacerbations. Current international guidelines recommend steroid preventive therapy for those with a history of exacerbations whose FEV1 is less than 50 per cent of predicted.
But the new study of 127 patients, published online by the Primary Care Respiratory Journal, found exacerbations were only slightly more common in patients below the FEV1 cut-off than in those above it.
Patients with an FEV1 lower than 50 per cent than expected experienced 2.5 exacerbations per year, compared with 2.2 for those whose lung function was above the threshold.
Study leader Dr John O'Reilly, consultant in general medicine at University Hospital Aintree in Liverpool, warned: 'This study shows FEV1 is not an accurate discriminator for exacerbations. The lung function-based criteria for management of COPD patients with recurrent exacerbations should be re-evaluated in the light of these data.'
GP respiratory experts said the results supported calls to look beyond lung function, with a second study published online by Respiratory Medicine finding walking distance was an accurate predictor of exacerbations.
Dr Kevin Gruffydd-Jones, committee member of the General Practice Airways Group and a GP in Box, Wiltshire, said: 'These findings are very interesting and show the level of lung function is not an accurate predictor of who has exacerbations of COPD.
'These studies suggest current guidelines for the man-
agement of COPD should be altered so combination inhaled steroids/LABA therapy should be based on the criteria that a patient is already experiencing exacerbations irrespective of lung function.'
Dr Rupert Jones, a GP in Plymouth and head of the respiratory research unit at Peninsula Medical School, said: 'If you look at a COPD patient you need to consider their lung function, number of exacerbations, MRC dyspnoea scale and smoking status.
'You need to look at COPD not just in terms of lung function.'
Gold guidelines say consider preventive therapy:
• With at least one exacerbation requiring oral steroids or antibiotics in previous 12 months and an FEV1 <50 per="" cent="">50>
ATS/ETS advise treatment in:
• Those with repeated exacerbations and FEV1 <50 per="" cent="">50>
But new study found:
• FEV1 does not accurately predict exacerbations
• Majority of patients with FEV1 =50 per cent predicted had at least one exacerbation
Researchers suggest also considering:
• previous exacerbations
• MRC dyspnoea scale
• smoking status