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Thorax 2010;65:150-156 doi:10.1136/thx.2009.115063
  • Chronic obstructive pulmonary disease

Longitudinal change of prebronchodilator spirometric obstruction and health outcomes: results from the SAPALDIA cohort

  1. N M Probst-Hensch1,
  2. I Curjuric2,
  3. B Pierre-Olivier3,
  4. U Ackermann-Liebrich2,
  5. R W Bettschart4,
  6. O Brändli5,
  7. M Brutsche6,
  8. L Burdet7,
  9. M W Gerbase3,
  10. B Knöpfli8,
  11. N Künzli2,
  12. M G Pons9,
  13. C Schindler2,
  14. J-M Tschopp10,
  15. T Rochat3,
  16. E W Russi11
  1. 1Chronic Disease Epidemiology, Institute of Social and Preventive Medicine, University of Zürich, Switzerland
  2. 2Institute of Social and Preventive Medicine at Swiss Tropical Institute, Basel, Switzerland
  3. 3Division of Pulmonary Medicine, University Hospitals of Geneva, Geneva, Switzerland
  4. 4Lungenzentrum, Hirslanden Klinik Aarau, Switzerland
  5. 5Zürcher Höhenklinik Wald, Switzerland
  6. 6Division of Pulmonary Medicine, Cantonal Hospital of St. Gallen, St. Gallen, Switzerland
  7. 7Hôpital Intercantonal de la Broye, Payerne, Switzerland
  8. 8FMH Pädiatrie, Pneumologie und Sportmedizin, Davos, Switzerland
  9. 9Dipartimento di Medicina, Ospedale Regionale di Lugano, Lugano, Switzerland
  10. 10Centre Valaisan de Pneumologie et Département de Médecine Interne du Centre Hospitalier du Centre du Valais, Crans-Montana, Switzerland
  11. 11Division of Pulmonary Medicine, University Hospital of Zürich, Zürich, Switzerland
  1. Correspondence to Dr N M Probst-Hensch, Institute of Social and Preventive Medicine, Chronic Disease Epidemiology, University of Zürich, Sumatrastr. 30, CH-8091 Zürich, Switzerland; Nicole.Probst{at}ifspm.uzh.ch
  • Received 13 February 2009
  • Accepted 13 October 2009
  • Published Online First 8 December 2009

Abstract

Background Understanding the prognostic meaning of early stages of chronic obstructive pulmonary disease (COPD) in the general population is relevant for discussions about underdiagnosis. To date, COPD prevalence and incidence have often been estimated using prebrochodilation spirometry instead of postbronchodilation spirometry. In the SAPALDIA (Swiss Study on Air Pollution and Lung Disease in Adults) cohort, time course, clinical relevance and determinants of severity stages of obstruction were investigated using prebronchodilator spirometry.

Methods Incident obstruction was defined as an FEV1/FVC (forced expiratory volume in 1 s/forced vital capacity) ratio ≥0.70 at baseline and <0.70 at follow-up, and non-persistence was defined inversely. Determinants were assessed in 5490 adults with spirometry and respiratory symptom data in 1991 and 2002 using Poisson regression controlling for self-declared asthma and wheezing. Change in obstruction severity (defined analogously to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) classification) over 11 years was related to shortness of breath and health service utilisation for respiratory problems by logistic models.

Results The incidence rate of obstruction was 14.2 cases/1000 person years. 20.9% of obstructive cases (n = 113/540) were non-persistent. Age, smoking, chronic bronchitis and non-current asthma were determinants of incidence. After adjustment for asthma, only progressive stage I or persistent stage II obstruction was associated with shortness of breath (OR 1.71, 95% CI 0.83 to 3.54; OR 3.11, 95% CI 1.50 to 6.42, respectively) and health service utilisation for respiratory problems (OR 2.49, 95% CI 1.02 to 6.10; OR 4.17 95% CI 1.91 to 9.13, respectively) at follow-up.

Conclusions The observed non-persistence of obstruction suggests that prebronchodilation spirometry, as used in epidemiological studies, might misclassify COPD. Future epidemiological studies should consider both prebronchodilation and postbronchodilation measurements and take specific clinical factors related to asthma and COPD into consideration for estimation of disease burden and prediction of health outcomes.

Footnotes

  • Additional figures and tables are published online only at http://thorax.bmj.com/content/vol65/issue2

  • NMP-H and IC contributed equally to this work.

  • Funding The Swiss National Science Foundation (grant nos 33CSCO-108796, 3247BO-104283, 3247BO-104288, 3247BO-104284, 3247-065896, 3100-059302, 3200-052720, 3200-042532, 4026-028099), the Federal Office for Forest, Environment and Landscape, the Federal Office of Public Health, the Federal Office of Roads and Transport, the canton’s government of Aargau, Basel-Stadt, Basel-Land, Geneva, Luzern, Ticino, Zurich, the Swiss Lung League, the canton’s Lung League of Basel Stadt/Basel Landschaft, Geneva, Ticino and Zurich.

  • Competing interests None.

  • Ethics approval The study was approved by the central ethics committee of the Swiss Academy of Medical Sciences and the respective Cantonal Ethics Committees of the eight study regions included in the study.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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