The many faces of COPD in real life: a longitudinal analysis of the NOVELTY cohort

Abstract

Background: The diagnosis of COPD requires the demonstration of non-fully reversible airflow limitation by spirometry in the appropriate clinical context. Yet, there are patients with symptoms and relevant exposures suggestive of COPD with either normal spirometry (pre-COPD) or preserved ratio but impaired spirometry (PRISm). Their prevalence, clinical characteristics and associated outcomes in a real-life setting are unclear.

Methods: To investigate them, we studied 3183 patients diagnosed with COPD by their attending physician included in the NOVELTY study (clinicaltrials.gov identifier NCT02760329), a global, 3-year, observational, real-life cohort that included patients recruited from both primary and specialist care clinics in 18 countries.

Results: We found that 1) approximately a quarter of patients diagnosed with (and treated for) COPD in real life did not fulfil the spirometric diagnostic criteria recommended by the Global Initiative for Chronic Obstructive Lung Disease (GOLD), and could be instead categorised as pre-COPD (13%) or PRISm (14%); 2) disease burden (symptoms and exacerbations) was highest in GOLD 3-4 patients (exacerbations per person-year (PPY) 0.82) and lower but similar in those in GOLD 1-2, pre-COPD and PRISm (exacerbations range 0.27-0.43 PPY); 3) lung function decline was highest in pre-COPD and GOLD 1-2, and much less pronounced in PRISm and GOLD 3-4; 4) PRISm and pre-COPD were not stable diagnostic categories and change substantially over time; and 5) all-cause mortality was highest in GOLD 3-4, lowest in pre-COPD, and intermediate and similar in GOLD 1-2 and PRISm.

Conclusions: Patients diagnosed COPD in a real-life clinical setting present great diversity in symptom burden, progression and survival, warranting medical attention.

FIGURE 1

Scatter plot of post-bronchodilator forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) (%) values versus post-bronchodilator FEV₁ (% predicted) in patients with a physician-assigned diagnosis of COPD included in this analysis (n=3183). According to their measured spirometric values, patients are categorised as pre-COPD, preserved ratio but impaired spirometry (PRISm), Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1–2 or GOLD 3–4. Proportions indicate the prevalence of each diagnostic category.

FIGURE 2

Alluvial plot of annual changes of the four diagnostic categories analysed here during follow-up, which includes all patients with complete data at all time points (n=995) and sets the minimum group change to 10 patients for visual clarity. Proportions denote the percentage of patients in each group. PRISm: preserved ratio but impaired spirometry; GOLD: Global Initiative for Chronic Obstructive Lung Disease.

FIGURE 3

Mean values of health status as assessed by a) total St George's Respiratory Questionnaire (SGRQ) score or b) total Chronic Airways Assessment Test (CAAT) score; c) moderate/severe annual exacerbations; and d) proportion of patients with more than one hospitalisation because of a COPD exacerbation per year in patients with pre-COPD, preserved ratio but impaired spirometry (PRISm), Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1–2 or GOLD 3–4, at baseline and each year during the 3-year follow-up. This graph includes all patients with data per visit, irrespective of whether they have data at other visits.

FIGURE 4

a) Mean±sem of forced expiratory volume in 1 s (FEV₁) values determined at baseline and during follow-up (3 years) versus mean age (years) in patients with pre-COPD, preserved ratio but impaired spirometry (PRISm), Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1–2 and GOLD 3–4 with valid data in all four visits (n=995). The mean±sem rate of absolute annual FEV₁ decline is shown for each group. b) FEV₁ values in each group at years (Y)1, 2 and 3 of follow-up, expressed as a percentage of the baseline (BSL) value (calculated as 100×(FEV_{1(Y1, Y2, Y3)} – FEV_1BSL)/FEV1_BSL).

FIGURE 5

All-cause mortality during 3-year follow-up in pre-COPD, preserved ratio but impaired spirometry (PRISm), Global Initiative for Chronic Obstructive Lung Disease (GOLD) 1–2 and GOLD 3–4 patients.