Pre- and post-bronchodilator airway obstruction are associated with similar clinical characteristics but different prognosis – report from a population-based study

Abstract

IntroductionAccording to guidelines, the diagnosis of COPD should be confirmed by post-bronchodilator (post-BD) airway obstruction on spirometry; however, in clinical practice, this is not always performed. The aim of this population-based study was to compare clinical characteristics and prognosis, assessed as mortality, between subjects with airway obstruction divided into pre- but not post-BD obstruction, post-BD airway obstruction (COPD), and subjects without airway obstruction.Materials and methodsIn 2002–2004, four adult population-based cohorts were reexamined with spirometry and structured interview. Subjects with airway obstruction, with a ratio of forced expiratory volume in 1 s to (forced) vital capacity <0.70 (n=993), were identified together with sex- and age-matched referents (n=993). These subjects were further divided into subjects with pre- but not post-BD airway obstruction (pre- not post-BD obstruction) and subjects with post-BD airway obstruction (COPD). Mortality data were collected until December 31, 2014.ResultsOut of 993 subjects with airway obstruction, 736 (74%) had COPD and 257 (26%) pre- not post-BD obstruction. Any respiratory symptoms, allergic rhinitis, asthma, exacerbations, and comorbidities were equally common among subjects with COPD and pre- not post-BD obstruction, but less common among nonobstructive subjects. Mortality was highest among subjects with COPD and higher in men than in women. In both sexes, COPD, but not pre- not post-BD obstruction, was associated with an increased risk for death compared to those without airway obstruction. When COPD was divided into Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages, GOLD 2 and 3–4 had an increased risk for death when compared to the nonobstructive group, also when adjusted for common confounders and comorbidities such as heart disease, diabetes, and anxiety/depression.ConclusionEven though subjects with COPD and pre- not post-BD obstruction had fairly similar presentation of clinical characteristics, only those with COPD, specifically GOLD stage ≥2, had increased risk for death when compared with nonobstructive subjects.

Incidence trends of airflow obstruction among European adults without asthma: a 20-year cohort study

“…The positive predictive value of AO for AO post-BD was lower in women than in men in our sample, which could be explained by differences among the subjects with AO. As reported by Sawalha and colleagues 5 , we also found that the percentage of ever smokers (79.7% vs 73.4%), the median number of lifetime pack-years (25 vs 20), and the percentage of subjects with productive cough (21.0% vs 14.5%), factors that may predict the occurrence of COPD 14 , were higher in men than in women with AO and valid post-bronchodilator spirometry at the 3 rd examination. In addition, our estimates of the positive predictive value (59.1% in males and 42.6% in females) were lower than the figure obtained by Schermer and colleagues (74.7% in both sexes) when the fixed cut-off definition of AO was used 4 .…”

“…spirometry, and the use of pre-bronchodilator measurements may lead to some misclassification of the disease 5 . However, post-bronchodilator spirometry has been adopted in epidemiological studies in recent years only.…”

The revised GOLD 2017 COPD categorization in relation to comorbidities

“…Indeed, the change in approach by GOLD was based on the observation that FEV 1 alone is not a strong predictor of exacerbation risk; consequently pharmacotherapy recommendations are now based on exacerbations and symptoms alone [6]. In view of the link between exacerbation risk and comorbidities, the revised approach is also in line with previous observations that spirometry alone does not correlate strongly with individual comorbidities [19,20]. Comorbidities definitely play a role in the impact and burden COPD, with cardiovascular events being one of the main causes of mortality [21,22].…”

Differences in diagnostic patterns of obstructive airway disease between areas and sex in Sweden and Finland - the Nordic EpiLung study

“…This was an unexpected finding and we cannot explain this difference between the countries. However, it has been argued that there are differences in clinical presentation between men and women with COPD, where for instance women present with more dyspnea but less sputum production than men (51,52). The prevalence of sputum production was similar among men and women in all the four study areas, while the prevalence of dyspnea was higher among women than among men.…”