Table 3

Informativeness* of spirometric Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades and ABCD groups related to all-cause mortality among participants with chronic obstructive pulmonary disease (COPD) in the HUNT2 Lung Study

Women (n=468)†Men (n=736)†
COPD classificationχ2(%)p Valueχ2(%)p Value
GOLD grades‡62.53(100)<0.00132.47(100)<0.001
ABCD groups§26.28(42)<0.00113.03(40)0.046
  • *The Cox null model included age (as the time scale), smoking (never, former, current, unknown) and education (<10, ≥10 years, unknown). The Cox alternative models included spirometric GOLD grades or ABCD groups in addition to all in the null model. The χ2 shows the difference in twice the log-likelihood between the null model and the alternative model. The most informative model has the highest value of χ2 and has been set to 100%.

  • †People with missing data on dyspnoea were excluded so that the results from the spirometric GOLD grades and the ABCD groups could be compared.

  • ‡COPD defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) <0.70 and graded as follows; GOLD 1=per cent predicted FEV1 (ppFEV1) ≥80; GOLD 2=50≤ ppFEV1 <80; GOLD 3=30≤ ppFEV1 <50; GOLD 4=ppFEV1 <30.

  • §ABCD groups defined as follows; A=dyspnoea ≤grade 1, GOLD 1 or 2, and ≤1 exacerbation last 12 months; B=dyspnoea ≥grade 2, GOLD 1 or 2, and ≤1 exacerbation last 12 months; C=dyspnoea ≤grade 1, and GOLD 3 or 4 or ≥2 exacerbations last 12 months; D=dyspnoea ≥grade 2, and GOLD 3 or 4 or ≥2 exacerbations last 12 months.