Prediction of COPD and Related Events Improves by Combining Spirometry and the Single Breath Nitrogen Test

• Chronic obstructive pulmonary disease (COPD) develops in small airways. Severity of small airway pathology relates to progression and mortality. The present study evaluated the prediction of COPD of a validated test for small airway disease, i.e. a slope of the alveolar plateau of the single breath nitrogen test (N-2-slope). The N-2-slope, spirometry, age, smoking habits, and anthropometric variables at baseline were obtained in a population-based sample (n = 592). The cohort was followed for first COPD events (first hospital admission of COPD or related conditions or death from COPD) during 38 years. During follow-up, 52 subjects (8.8%) had a first COPD event, of which 18 (3.0%) died with a first COPD diagnosis. In the proportional hazard regression analysis adjusted for age and smoking habits, the cumulative COPD event incidence increased from 5% among those with high forced expired volume in one second (FEV1) to 25% among those with low FEV1, while increasing from 4% among those with the lowest N-2-slope to 26% among those with the highest. However, combining the N-2-slope and FEV1 resulted in considerable synergy in the prediction of first COPD event and even more so when taking account of smoking habits. The cumulative COPD event incidence rate was 75% among heavy smokers with the highest N-2-slope and lowest FEV1, and less than 1% among never smokers with the lowest N-2-slope and highest FEV1. Thus, combining the results of the single breath N-2-slope and FEV1 considerably improved the prediction of COPD events as compared to either test alone.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Lungmedicin och allergi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Respiratory Medicine and Allergy (hsv//eng)

Nyckelord

Epidemiology

longitudinal study

COPD event

respiratory functions tests

obstructive pulmonary-disease

small-airway obstruction

heart-failure

lung-function

smokers

volume

hospitalizations

emphysema

n2-test

decline

Respiratory System

anescu dc

1987

american review of respiratory disease

v135

p585

Epidemiology

Publikations- och innehållstyp

ref (ämneskategori)

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