Table 4.
Clinical Characteristics of Participants without COPD by Spirometric Criteria by Presence of Emphysema on CT.
| Clinical characteristic | Mean or proportion of clinical characteristic among MESA COPD Study participants without COPD adjusted for age, gender, race-ethnicity, and smoking status (95% CI) | P-value* | |
|---|---|---|---|
| Emphysema absent N=138 |
Emphysema present N=28 |
||
| Body mass index | 28 (26 to 30) | 27 (26 to 29) | 0.41 |
| Pack-years | 31 (27 to 35) | 40 (33 to 47) | 0.03 |
| Proportion with mMRC dyspnea scale ≥2 – %a | 7.0 (2.9 to 11) | 0.0 (0.0 to 9) | 0.36 |
| Percent predicted FEV1 | 99 (95 to 102) | 101 (95 to 107) | 0.51 |
| Percent predicted FVC | 96 (93 to 99) | 100 (94 to 106) | 0.20 |
| FEV1/FVC | 0.78 (0.77 to 0.79) | 0.77 (0.75 to 0.79) | 0.16 |
| Percent predicted RV‡ | 74 (61 to 87) | 86 (69 to 103) | 0.17 |
| Percent predicted FRC‡ | 90 (80 to 101) | 104 (90 to 118) | 0.11 |
| Percent predicted TLC‡ | 89 (82 to 96) | 98 (88 to 107) | 0.07 |
| Percent predicted DLCO/VA‡ | 79 (72 to 86) | 73 (64 to 82) | 0.20 |
| Percent predicted 6MWDa | 94 (90 to 99) | 83 (75 to 91) | 0.01 |
| Percent emphysema<-950HU | 1.0 (0.8 to 1.3) | 0.9 (0.6 to 1.4) | 0.63 |
| Proportion with SpO2 ≤ 95% - % | 3.3 (0.1 to 15) | 12 (2.5 to 40) | 0.10 |
| White blood cell count – ·109/L | 6.2 (5.8 to 6.5) | 6.9 (6.2 to 7.5) | 0.06 |
P-values represent bi-variate comparison of mean or proportion using Chi-square, Fisher’s exact or Student t-test where appropriate.
Plethysmography and diffusing capacity were measured on validation participants only.
6MWD and mMRC dyspnea scale were measured in a subset of participants (n=145 and n=156 participants, respectively).
Abbreviations: MESA denotes Multi-Ethnic Study of Atherosclerosis, COPD chronic obstructive pulmonary disease, CI confidence interval, mMRC modified Medical Research Council, FEV1 forced expired volume in the first second, FVC forced vital capacity, RV residual volume, FRC functional residual capacity, TLC total lung capacity, DLCO/VA diffusing capacity of the lung for carbon monoxide divided by alveolar volume, 6MWD six minute walk distance, HU Hounsfield units, and SpO2 pulse-oximeter estimated arterial oxygen-hemoglobin saturation.