How difficult is it to diagnose people with COPD?

This article is aimed at challenging some of our conscious and unconscious views about chronic obstructive pulmonary disease (COPD) and the patients with COPD we care for.

Here, we’ll look at some of the more common areas of diagnosis with a slightly different perspective. I hope it will allow you to reflect on your own practice and those of your colleagues, and think about challenging our current system.

Of course, it will be grounded in the major English guidelines from the National Institute for Clinical Excellence (NICE)^[1] and the strategy and report produced on behalf of the Global Initiative for Chronic Obstructive Lung Disease (GOLD).^[2]

COPD assumptions

Perhaps the first thing to consider is the assumption that everyone who smokes will develop COPD, and those who don’t smoke will be fine.

Firstly, is it only people who smoke who develop COPD? Although tobacco smoking is a key environmental risk factor of COPD, it is now recognised that around 30% of all COPD cases in the world occur in never-smokers.^[3]

In a research programme of 5,176 adults, the prevalence of COPD (FEV₁/FVC<lower limits of normal) in never-smokers was 6.4%, constituting 27% of all COPD subjects.^[4]

Through dedicated research it’s been highlighted that disease processes can begin in early life, that there is a complex interplay of a range of risk factors in addition to smoking – including genetics, respiratory infections, and air pollution – and that COPD is a spectrum of lung disease that needs personalised treatment approaches.^[5] This fits in with the 2022 Lancet Commission work on improving the care of people with COPD, which argues that it is time for a fundamental change in thinking about COPD.^[5]

Secondly, do all smokers develop COPD? Well, data from the World Health Organization suggests tobacco smoking accounts for over 70% of COPD cases in high-income countries, and in low-and-middle-income countries, 30–40% of COPD cases.^[6]

We should also be thinking about our patients who are smoking heroin and marijuana with tobacco,^[7],[8] who appear prone to developing COPD as those smoking water (shisha pipes),^[9] where estimates suggest that in a shisha session, a shisha smoker can inhale the same amount of smoke as a cigarette smoker consuming over 100 cigarettes.^[10]

Changes in diagnosing COPD

The diagnosis is simple if you look at the NICE COPD summary – which emphasises the importance of a good history and examination, with a full blood count, measurement of the body mass index, a chest X-ray all suggesting COPD which would be confirmed by post bronchodilator spirometry showing an obstructive picture.^[1]

We should remember a diagnosis of COPD (emphysema or chronic bronchitis) was often made based on symptoms of a cough for more than three months usually with a smoking history and with hyperinflation on a chest X-ray.^{[11],[12],[13]} A personal audit of new patients in my practice (2014-2018) unfortunately has demonstrated that more than 60% of people who join our list with a new or previous diagnosis of COPD when there was no spirometry available have normal spirometry when we tested. Many had been diagnosed in both primary and secondary care on the basis of symptoms or an X-ray appearance.

We are all aware that since the pandemic there have been problems with access to spirometry across our healthcare system and that new diagnoses of COPD have reduced dramatically.^[14] This is something that we need to aim to improve as a healthcare system – but this still demands a robust diagnosis to inform treatment.

We are also now more aware of GOLD suggesting using a fixed ratio of FEV₁/ FVC,^[2] whereas NICE has moved to suggesting use of more clinical judgement and the lower limit of normal guidance,^[1] like the Primary Care^[15] and ARTP guidance.^[16]

This is on top of the increasing number of people who are having computed tomography (CT) scans performed as part of investigations who are found to have evidence of emphysema, for which NICE have produced some outline management advise on evaluation.^[1]

Looking forward

It has been estimated that the lung cancer screening in the 60-75 year old population with a previous history of smoking will result in around 68-73% having radiological evidence of emphysema on their scan.^[17] This correlated to 57% having (pre) bronchodilator spirometry suggesting COPD.^[17]

As the move towards lung cancer screening (lung health checks) progresses, it would be hoped that spirometry is performed in this cohort and that findings both radiologically and spirometrically are managed well on top of potentially detecting early lung cancer.^[17]

In summary, the diagnosis of COPD is not quite as straightforward as it appears, and we need to use clinical expertise along with appropriate tests and assessment to help our patients. We should not assume that all smokers will develop COPD – and that it is only smokers who develop COPD.

Any advice given and opinions expressed in this article are those of the author and do not reflect the view of Chiesi Limited (Chiesi).  All content in this article is for informational and educational purposes only.  Although Chiesi strives to always provide accurate information, it is not responsible for and does not verify for accuracy any of the information contained within.

[1] National Institute for Clinical Excellence. NG 115 Chronic obstructive pulmonary disease in over 16s: diagnosis and management. NICE; 2019. Available at: https://www.nice.org.uk/guidance/ng115

[2] Global Initiative for Chronic Obstructive Lung Disease. 2024 Gold Report. Available at: https://goldcopd.org/2024-gold-report/

[3] Rodríguez García C, Ruano-Ravina A, Pérez Ríos M, et al. Clinical characteristics of chronic obstructive pulmonary disease in never-smokers: A systematic review. Respir Med. 2023; 214: 107284

[4] Tan WC, Sin DD, Bourbeau J, et al. Characteristics of COPD in never-smokers and ever-smokers in the general population: results from the CanCOLD study. Thorax. 2015; 70(9): 822-829

[5] The Lancet. Changing how we see COPD. Available at: https://www.thelancet.com/action/showPdf?pii=S2213-2600%2823%2900433-2

[6] World Health Organization. Smoking is the leading cause of chronic obstructive pulmonary disease. Available at: https://www.who.int/news/item/15-11-2023-smoking-is-the-leading-cause-of-chronic-obstructive-pulmonary-disease

[7] Bitar AN, Khan AH, Sulaiman SAS, Ali IABH, et al. The Association between Chronic Heroin Smoking and Chronic Obstructive Pulmonary Disease. J Pharm Bioallied Sci. 2021; 13(Suppl 2): S1215-S1223

[8] Tan WC, Lo C, Jong A, et al. Marijuana and chronic obstructive lung disease: a population-based study. CMAJ. 2009; 180(8): 814-820

[9] El-Zaatari ZM, Chami HA, Zaatari GS. Health effects associated with waterpipe smoking. Tob Control. 2015; 24 Suppl 1(Suppl 1): i31-i43

[10] British Heart Foundation. Shisha. Available at: https://www.bhf.org.uk/informationsupport/risk-factors/smoking/shisha

[11] Widysanto A, Mathew G. Chronic Bronchitis. In: StatPearls. Treasure Island (FL): StatPearls Publishing; November 28, 2022. Available at: https://www.ncbi.nlm.nih.gov/books/NBK482437/

[12] Watson RA, Pride NB. Early History of Chronic Obstructive Pulmonary Disease 1808-1980. COPD. 2016; 13(2): 262-273

[13] Friedman PJ. Imaging studies in emphysema. Proc Am Thorac Soc. 2008; 5(4): 494-500

[14] Asthma + Lung UK. Right test, right time. Available at: https://www.asthmaandlung.org.uk/diagnosing-problem-right-test-right-time-report

[15] Levy ML, Quanjer PH, Booker R, Holmes S, et al. Standards for diagnostic spirometry within session repeatability in primary care. Primary Care Respiratory Journal. 2012; 21(3): 252-3

[16] Sylvester KP, Clayton N, Cliff I, et al. ARTP statement on pulmonary function testing 2020. BMJ Open Respir Res. 2020; 7(1): e000575

[17] Ruparel M, Quaife SL, Dickson JL, et al. Prevalence, Symptom Burden, and Underdiagnosis of Chronic Obstructive Pulmonary Disease in a Lung Cancer Screening Cohort. Ann Am Thorac Soc. 2020; 17(7): 869-878