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Table 4 Correlations between gas trapping measures and quantitative outcomes in subjects with severe emphysema (Insp -950HU > 15% ex-smokers, Insp -950HU > 14% current smokers)

From: Paired inspiratory-expiratory chest CT scans to assess for small airways disease in COPD

 

Correlations

 

N

Mean (SD)

Exp−856

E/I MLA

RVC856-950

Residual

FEV1 % predicted

1185

41.2 (19.9)

−0.69‡

−0.73‡

−0.73‡

−0.16‡

FVC % predicted

1185

75.7 (21.1)

−0.49‡

−0.56‡

−0.57‡

−0.17‡

FEV1/FVC

1185

0.40 (0.12)

−0.66‡

−0.62‡

−0.62‡

−0.08*

FEF25-75

1185

0.42 (0.38)

−0.56‡

−0.61‡

−0.61‡

−0.18‡

FRC/TLC ratio

1188

0.69 (0.12)

0.80*

0.93*

0.87*

0.44*

6MWD

1135

1116 (404)

−0.31‡

−0.40‡

−0.43‡

−0.01NS

Exacerbation frequency

1188

0.8 (1.2)

0.10†

0.12‡

0.13‡

−0.02NS

SGRQ total

1188

44.9 (19.9)

0.32‡

0.41‡

0.43‡

0.09*

MMRC dyspnea

1183

2.5 (1.3)

0.34‡

0.38‡

0.42‡

0.01NS

  1. Pearson correlation coefficients are shown.
  2. *p < 0.01.
  3. †p < 0.001.
  4. ‡p < 0.0001.
  5. NS = not significant (p > 0.05).