NICE should redraw COPD diagnosis guidelines because they are likely causing overdiagnosis in men and underdiagnosis in women, respiratory experts have said.
Dr Mark Levy, a GPSI in respiratory medicine based in Harrow, and Professor Martin Miller, from the University of Birmingham, warn up to 13% of people thought to have COPD may have been misdiagnosed with the condition, while one in eight cases are likely to be missed.
NICE adopted use of a single, ‘pragmatic’ measure of airways obstruction from the Global Initiative for Obstructive Lung Disease (GOLD) in 2010, which means people are diagnosed with COPD if they have a post-bronchodilator ratio of FEV1/FVC cut-off of less than 0.7, regardless of any other factors.
However, writing in a BMJ commentary, Dr Levy and Professor Miller say this is causing over-diagnosis in some patients – particularly older men. Many of these will have heart disease that is left undiagnosed as a result of their breathlessness being put down to COPD, they say – a risk compounded by the known cardiac side effects of certain COPD inhalers.
Meanwhile evidence shows COPD can be missed in other patients using the NICE/GOLD fixed ratio, particularly women under 50.
The experts call for the NICE criteria to be modified to apply lower limit of normal (LLN) standards – which take into account natural variations in lung function according to age, sex, height and ethnicity – to the FEV1/FVC reading.
In the meantime they say GPs should start using the LLN when assessing patients for COPD.
They write: ‘Adoption of this criterion, which is programmed for spirometry software, will help to improve patient care through more accurate diagnosis of obstructive airflow diseases as well as leading to other investigations for alternative diagnoses when appropriate.’
NICE said guidelines for COPD management are due for review next year when a decision would be made on whether to update the diagnostic criteria.
A spokesperson said: ‘The NICE COPD guideline is due to be reviewed in March 2016; at this point a formal check will be conducted to identify any relevant evidence that may impact the recommendations and a decision will be made as to whether any recommendations need updating. We welcome any new research that will help further develop our guidance.’