Diagnosis of chronic obstructive pulmonary disease, simpler is better. Complexity and simplicity

Spirometry is not enough to diagnose COPD in epidemiological studies: a follow-up study

A hallmark of the diagnosis of chronic obstructive pulmonary disease (COPD) is the measurement of post-bronchodilator (post-BD) airflow obstruction (AO) by spirometry, but spirometry is not enough for the provision of a clinical diagnosis. In the majority of previous epidemiological studies, COPD diagnosis has been based on spirometry and a few clinical characteristics. The aim of our study was to identify outcomes in patients newly diagnosed with airflow obstruction (AO) based on a diagnostic work-up conducted as part of a population-based cross-sectional study in North-Western Russia. Spirometry was performed before (pre-BD) and after BD administration, and AO was defined using the FEV1/FVC <0.70 and FEV1/FVC Collapse

Key Words Collapse

MESH Headings

• Bronchodilator Agents/therapeutic use
• Cross-Sectional Studies
• Female
• Follow-Up Studies
• Forced Expiratory Volume/drug effects
• Humans
• Male
• Middle Aged
• Pulmonary Disease, Chronic Obstructive/diagnosis
• Pulmonary Disease, Chronic Obstructive/drug therapy
• Pulmonary Disease, Chronic Obstructive/epidemiology
• Russia/epidemiology
• Spirometry
• Vital Capacity/drug effects

Collapse

Grants Collapse

Affiliation(s)

Elena Andreeva Institute of Health and Society, Université Catholique de Louvain, IRSS, Clos Chapelle-aux-Champs, 30/10.15, 1200, Brussels, Belgium Department of Family Medicine, Northern State Medical University, pr. Troitsky, 51, 163000, Arkhangelsk, Russia
Marina Pokhaznikova Department of Family Medicine, North-Western State Medical University named after I.I. Mechnikov, Kirochnaya str., 41, 191015, St. Petersburg, Russia
Anatoly Lebedev Department of Family Medicine, North-Western State Medical University named after I.I. Mechnikov, Kirochnaya str., 41, 191015, St. Petersburg, Russia
Irina Moiseeva Department of Family Medicine, North-Western State Medical University named after I.I. Mechnikov, Kirochnaya str., 41, 191015, St. Petersburg, Russia
Olga Kuznetsova Department of Family Medicine, North-Western State Medical University named after I.I. Mechnikov, Kirochnaya str., 41, 191015, St. Petersburg, Russia
Jean-Marie Degryse Institute of Health and Society, Université Catholique de Louvain, IRSS, Clos Chapelle-aux-Champs, 30/10.15, 1200, Brussels, Belgium. Department of Public Health and Primary Health Care, K.U.Leuven, Kapucijnenvoer 33, B3000, Leuven, Belgium.

Collapse

The Prevalence of Chronic Obstructive Pulmonary Disease by the Global Lung Initiative Equations in North-Western Russia

BACKGROUND

The prevalence of chronic obstructive pulmonary disease (COPD) varies in different countries, while the cut-off for airflow obstruction (AO) is still contested. No COPD prevalence data based on the Global Lung Initiative (GLI) 2012 equations are available in Russia.

OBJECTIVES

This study aims to assess AO prevalence by the GLI lower limit of normal (GLI-LLN) and the fixed cut-off, to identify AO risk factors and to assess the diagnostic value of respiratory symptoms in north-western Russia.

METHODS

In a north-western Russian population-based sample of 2,974 adults aged 35-70 years, data on socio-demographics, smoking, occupational exposures and respiratory symptoms were collected, and spirometry was performed before and after bronchodilator (BD) administration.

RESULTS

The AO prevalence was 6.8% (95% CI 5.8-7.9) based on the fixed and 4.8% (95% CI 3.9-5.7) based on the GLI-LLN cut-off. 22.5% of the participants with post-BD AO had a positive bronchodilator test, and 1% showed a paradoxical BD response. Of the environmental factors studied, only smoking was independently associated with AO (odds ratio 2.47, 95% CI 1.60-3.82). The positive predictive value of respiratory symptoms for AO was 11% based on the fixed and 8% based on the GLI-LLN cut-off.

CONCLUSIONS

In a sample of adults in north-western Russia, the AO prevalence by the GLI-LLN cut-off was lower than that by the fixed cut-off. The predictive value of respiratory symptoms was low.

Estimating population prevalence of potential airflow obstruction using different spirometric criteria: a pooled cross-sectional analysis of persons aged 40-95 years in England and Wales

OBJECTIVES

Consistent estimation of the burden of chronic obstructive pulmonary disease (COPD) has been hindered by differences in methods, including different spirometric cut-offs for impaired lung function. The impact of different definitions on the prevalence of potential airflow obstruction, and its associations with key risk factors, is evaluated using cross-sectional data from two nationally representative population surveys.

DESIGN

Pooled cross-sectional analysis of Wave 2 of the UK Household Longitudinal Survey and the Health Survey for England 2010, including 7879 participants, aged 40-95 years, who lived in England and Wales, without diagnosed asthma and with good-quality spirometry data. Potential airflow obstruction was defined using self-reported physician-diagnosed COPD; a fixed threshold (FT) forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) ratio <0.7 and an age-specific, sex-specific, height-specific and ethnic-specific lower limit of normal (LLN). Standardised questions elicited self-reported information on demography, smoking history, ethnicity, occupation, respiratory symptoms and cardiovascular disease.

RESULTS

Consistent across definitions, participants classed with obstructed airflow were more likely to be older, currently smoke, have higher pack-years of smoking and be engaged in routine occupations. The prevalence of airflow obstruction was 2.8% (95% CI 2.3% to 3.2%), 22.2% (21.2% to 23.2%) and 13.1% (12.2% to 13.9%) according to diagnosed COPD, FT and LLN, respectively. The gap in prevalence between FT and LLN increased in older age groups. Sex differences in the risk of obstruction, after adjustment for key risk factors, was sensitive to the choice of spirometric cut-off, being significantly higher in men when using FT, compared with no significant difference using LLN.

CONCLUSIONS

Applying FT or LLN spirometric cut-offs gives a different picture of the size and distribution of the disease burden. Longitudinal studies examining differences in unscheduled hospital admissions and risk of death between FT and LLN may inform the choice as to the best way to include spirometry in assessments of airflow obstruction.