About COPD and associated comorbidities

Comorbidity

People with chronic obstructive pulmonary disease (COPD) often have other chronic and long-term conditions. This is called ‘comorbidity’, which describes any additional disease that is experienced by a person with a disease of interest (the index disease). Comorbidities often share common risk factors, and are increasingly seen as acting together to determine the health outcome.

Australians diagnosed with one or more chronic conditions often have complex health needs, die prematurely and have poorer overall quality of life (AIHW 2018). In terms of comorbidities, in 2017–18 one in five Australians (20%) had two or more chronic conditions (ABS 2018). As people age, they are more likely to have more than one chronic condition. Because COPD is more likely to occur in older people, people with COPD also commonly experience a range of other chronic conditions (Chatlia et al. 2008; Divo et al. 2012). These comorbidities contribute to ill health and risk of death in all stages of COPD, and the incidence of hospitalisation for non-respiratory causes is increased in patients with COPD (Franssen & Rochester 2014). As well, when people are admitted for non-respiratory causes, they have a longer length of hospital stay and are more likely to die if they also have COPD (Holguin et al. 2005).

The chronic conditions that have been selected for this COPD comorbidity analysis are: arthritis, asthma, back problems, cancer, diabetes, heart, stroke and vascular disease, kidney disease, mental and behavioural conditions and osteoporosis. They have been selected because they are common in the general community and cause significant burden. Other chronic conditions that are found commonly in people with COPD, and that can impact COPD, include bronchiectasis and obstructive sleep apnoea (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019). COPD is also associated with an increased risk of lung cancer and gastro-oesophageal reflux disease (GORD) (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).

In February 2019, the Department of Health released the National Strategic Action Plan for Lung Conditions (the Action Plan), which includes COPD in its scope. The Action Plan ‘provides a detailed, person-centred roadmap for addressing one of the most urgent chronic conditions facing Australians’ (Department of Health 2019). The Action Plan ‘outlines a comprehensive, collaborative and evidence-based approach to reducing the individual and societal burden of lung conditions and improving lung health’ (Department of Health 2019). The Action Plan acknowledges as with most chronic conditions, lung disease may co-exist with other common chronic conditions. The Action Plan addresses these comorbidities when clinically relevant to a patient living with lung condition(s) (Department of Health 2019). For more information, see National Strategic Action Plan for Lung Conditions.

Treatment and management

Comorbidities can complicate management options and multiply the effects of chronic conditions (Van der Molen 2010). Physicians may need to prescribe medications for one condition that may exacerbate another existing comorbid condition. For example, some bronchodilator medications prescribed for COPD may worsen glaucoma (increased pressure in the eyes), or can cause urinary problems in men with an enlarged prostate. Use of steroid tablets for COPD exacerbations (or flare-ups) may contribute to weakening of the bones (osteoporosis) (AIHW 2019).

COPD has a high rate of comorbidity with cardiovascular disease (CVD) (Bhatt et al. 2014). Beta‑blocker medications are recommended for management of acute coronary syndromes, cardiac failure and sometimes for irregular heartbeat and hypertension. However, these medications can cause severe flare-ups in people with asthma and so have frequently been withheld from people with COPD (AIHW 2019). Despite this, recent evidence suggests that beta-blockers may be safe and helpful for managing COPD (Bhatt et al. 2016), though the COPD-X Plan states that despite a paucity of evidence to suggest harm, beta-blockers are still under-utilised in COPD for guideline-based indications such as systolic heart failure (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).

Establishing a better understanding of the common comorbidities of COPD may help with the diagnosis of comorbid conditions. For example, coronary artery disease is common in patients with COPD and is underdiagnosed (Reed et al. 2012). Optimal management of any individual patient with COPD should include identification and management of comorbidities and anticipation of increased risks associated with those comorbidities in the presence of COPD (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).

Prevention and diagnosis can be improved by a better understanding of risk factors for the development of COPD. Tobacco smoking, air pollution, poor nutrition and serious childhood lung infections are all known risk factors for developing COPD (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019). More information on risk factors can be found in the section Risk factors associated with COPD.

Treatment strategies that target modifiable behaviours can be used to manage various chronic diseases, for example, diet, exercise, weight control, and smoking cessation or reduction (Bauer et al. 2014). Smoking cessation is the most important intervention to prevent the worsening of COPD (Lung Foundation Australia & the Thoracic Society of Australia and New Zealand 2019).