More patients with COPD are being misdiagnosed than correctly diagnosed, according to data from the Canadian Cohort Obstructive Lung Disease (CanCOLD) study.

Lead investigator Professor Jean Bourbeau told the Respiratory Insights Forum that the population-based study found undiagnosed and overdiagnosed COPD in the community was five times more common than correctly diagnosed COPD patients¹.

Professor Bourbeau, director of the COPD Clinic and Pulmonary Rehabilitation Unit at the McGill University Health Centre, said the findings also showed high rates of hospitalisation, and visits to the emergency department and GP in the overdiagnosed group.

Another study from CanCOLD² showed the previously undiagnosed COPD patients were also having a significant impact on healthcare utilisation by presenting acutely for exacerbation-like events.

“The data suggests many patients are sick but not recognised as having a chronic condition. Can we change the course of these patients if we recognised and treated them appropriately?”

Professor Bourbeau said CanCOLD had also demonstrated the impact of both undiagnosed and diagnosed COPD in the workplace³.

The study found absenteeism was higher in people with physician-diagnosed COPD than in those undiagnosed with COPD before their entry into the study. However rates of presenteeism – being at work but not as productive – were similar in both groups.

“The data, especially Gershon and Labonte^1,3, are pretty definitive that misdiagnosis has a practical impact and certainly on the healthcare system. I’m always surprised that these studies are not given or receiving a lot of attention,” he told the limbic.

“One of the advantages of a population-based sample is that we can talk not only about the overdiagnosis – because overdiagnosis is a big topic right now and something you can assess relatively easily – but underdiagnosis, which is not something that has been assessed very well.”

“And there is a cost not only to overdiagnosis as we know that patients may be on treatment that is inappropriate and there may be side effects and costs. But underdiagnosis is something that we don’t know and what we don’t know about, we don’t care about.”

He said the fact a chronic condition was being treated acutely and not being diagnosed reflected the pre-eminance of the acute care model.

“It’s probably easier to do something acutely than recognise that there is a chronic disease.”

Imaging markers for COPD

Professor Bourbeau said there was a need for new markers in COPD additional to spirometry.

“In other chronic diseases there are a lot of blood tests that can be done and very often blood tests that are quite easily accessible and standardised.”

More work from CanCOLD suggested imaging held some promise in identifying early disease and guiding therapy⁴.

The study found CT emphysema and bronchial wall thickening discriminated between patients with and without airflow limitation and between levels of severity.

It supported the future use of radiological markers to identify patients with early COPD who do not demonstrate abnormal spirometry.

He added a total airway count on CT using commercially available software may reflect some of the airway attrition that occurs early in COPD – the so-called ‘quiet zone’ – and predict accelerated COPD progression⁵.

“It has to start with the research, and we are there now, to show using this technology if treatment is effective or to select the right population of patients. You don’t want to have a biological treatment with the costs and the potential side effects that is not for the right patients.”

“There is no payer who is going to pay for a treatment that is so expensive if it is not in a very select population – the right treatment for the right patient at the right time.”

References

1. Gershon AS et al. Health Services Burden of Undiagnosed and Overdiagnosed COPD. Chest. 2018:153(6):1336–1346. https://journal.chestnet.org/article/S0012-3692(18)30238-1/fulltext
2. Labonte LE et al. Undiagnosed Chronic Obstructive Pulmonary Disease Contributes to the Burden of Health Care Use. Data from the CanCOLD Study. AJRCCM. 2016;194(3). https://www.atsjournals.org/doi/abs/10.1164/rccm.201509-1795OC
3. de Sousa Sena R et al. Work productivity loss in mild to moderate COPD: lessons learned from the CanCOLD study. ERJ. 2017;50(3):1701154. http://erj.ersjournals.com/content/50/3/1701154.figures-only
4. Tan WC et al. Findings on Thoracic Computed Tomography Scans and Respiratory Outcomes in Persons with and without Chronic Obstructive Pulmonary Disease: A Population-Based Cohort Study. PLoS ONE. 2016:11(11): e0166745. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0166745
5. Kirby M et al. Total Airway Count on Computed Tomography and the Risk of Chronic Obstructive Pulmonary Disease Progression. Findings from a Population-based Study. AJRCCM. 2018;197(1):56-65. https://www.ncbi.nlm.nih.gov/pubmed/28886252