March 3, 2023
Clinical course of COPD

Chronic obstructive pulmonary disease (COPD) is characterised by persistent airway symptoms and airflow limitation due to airway inflammation and irritation (chronic bronchitis) and / or alveolar abnormalities (emphysema). COPD is caused by significant exposure to noxious particles or gases. The main risk factor for developing COPD is tobacco smoking, but other environmental exposures, such as biomass fuel exposure and air pollution, may also contribute.

The most common airway symptoms are dyspnoea, a cough, and extensive sputum production, which may significantly impact daily life. Patients with COPD may experience exacerbations, periods of acute symptom worsening that require treatment with oral corticosteroids and / or antibiotics. The diagnosis of COPD is made in patients over 40 years of age with respiratory symptoms, a relevant smoking history (more than 10 pack years), or other relevant exposure, and a persistent airflow limitation during spirometry testing after maximal bronchodilation (Z-score of the FEV1 / FVC ratio < -1.64). Usually, COPD is diagnosed by the GP.

Management of COPD involves stop-smoking counselling, dietary advice to prevent being under or overweight, exercise advice, the prescription of inhaled bronchodilators, and regular monitoring of symptoms and limitations. In case of the insufficient effect of one long-acting bronchodilator, a second bronchodilator from the other group can be added. If patients show frequent exacerbations, inhaled corticosteroids can be prescribed. A combination of two different types of bronchodilators plus corticosteroid inhalators is called ‘triple therapy’.

How is COPD recorded in FaMe-Net?

In ICPC-2, COPD (including chronic bronchitis) is recorded as R95. Exacerbations of COPD cannot be recorded separately within ICPC-2.

Epidemiology of COPD in FaMe-Net

The incidence of COPD is 0.8 per 1000 patient years. Incidence is highest in patients ≥ 75 years (4.1 per 1000 patient years) with more male than female patients being diagnosed (5.1 versus 3.3 per 1000 patient years in those aged 75+). This means that, per 1000 patients aged 75+ in a year, four new diagnoses of COPD are made (five among men and three among women aged 75+). The incidence of COPD has gradually decreased over the last years. Link/Figure 1

COPD has a mean prevalence of 12.0 patients per 1000 patient years, meaning that among 1000 patients in a year, 12 patients have COPD and sought help for COPD from their GP throughout the year. Among patients older than 65, more men than women have been diagnosed with COPD. The prevalence is highest in patients aged 75+ years (78.1 per 1000 patient years). Link/Figure 2

In patients aged over 65 years COPD is the 14th most commonly present condition in the GP patient population. Link/Table 3 The prevalence of COPD has decreased noticeably since 2014, meaning that the proportion of the patient population of GPs who have COPD and contact the GP for COPD has decreased. Link/Figure 2

The higher number of prevalence compared to incidence indicates that COPD is a chronic disease, requiring continued GP attention after diagnosis.

Which initial RFEs do patients with COPD present to their GP?

The two most common symptoms as initial reasons for encounter (RFE) for COPD are shortness of breath (R02) and cough (R05). Link/Table 4 More female than male patients present with shortness of breath as the initial RFE: 27% of all new diagnoses in women (Link/Table 5) versus 16% in men (Link/Table 6). In men, a new diagnosis of COPD is more likely to start with self-suspected COPD (RFE R95) at initial contact (in 7%, compared to <1% in women) or, more commonly (in 22%), with an administrative procedure (RFE *62). This means that the diagnosis is for the first time reported in a specialist letter, or that the episode starts with a request for a letter / declaration. In women, RFE *62 is the initial RFE in 13% of episodes only.

How do FaMe-Net GPs act?

In one calendar year, in 78% of the episodes of COPD, medication is prescribed by the GP. Only in 7% of the episodes are patients referred to a specialist (Link/Table 7) throughout the year, generally to a pulmonologist. Link/Table 8 In 3% of the episodes, patients are referred to the physical therapist, in the course of one calendar year. Link/Table 9 These percentages may seem relatively low but note they are calculated per calendar year, not throughout the entire episode of COPD.

When prescribing medication, GPs mostly prescribe inhaled bronchodilators, such as anticholinergics and selective beta-2 adrenoreceptor agonists. Link/Table 10 Since 2015, the Dutch College of General Practitioners’s COPD guideline recommends prescribing inhaled corticosteroids only to patients with two or more exacerbations or at least one hospital admission due to COPD in one year. This advice did not seem to affect the prescription behaviour of GPs as, since 2016, the percentage of prescriptions of inhaled corticosteroids as a single device or in combination with one or more bronchodilators (ATC codes R03AK, R03BA, and R03AL) is still as high as in previous years (50% in 2014-2015 (Link/Table 10) versus 51% in 2016-2021 (Link/Table 11), respectively). Since the introduction of so-called ‘triple therapy’ inhalers in 2017, the percentage of prescriptions for these inhalers (R03AL) has shown a tremendous increase, up to 25%, in 2021. Link/Table 12