TABLE 6.
POST-HOC CORRELATION ANALYSIS TO DETERMINE RELATIONSHIP BETWEEN BIOMARKERS IN SPUTUM AND SPIROMETRIC MEASUREMENTS IN HEALTHY SMOKERS AND SMOKERS WITH STAGE II CHRONIC OBSTRUCTIVE PULMONARY DISEASE
| FEV1, % Predicted |
FEV1/FVC Ratio |
|||
|---|---|---|---|---|
| Biomarker | Nonnormalized | Normalized | Nonnormalized | Normalized |
| Apolipoprotein A1 | −0.042 (0.73) | 0.17 (0.17) | −0.07 (0.54) | 0.21 (0.067) |
| Albumin | −0.057 (0.64) | 0.19 (0.13) | −0.18 (0.11) | 0.001 (0.99) |
| α2-HS glycoprotein | −0.061 (0.62) | 0.068 (0.58) | −0.2 (0.08) | −0.069 (0.54) |
| Transthyretin | −0.141 (0.25) | −0.04 (0.73) | −0.26 (0.02)* | −0.18 (0.11) |
| Lipocalin-1 | 0.07 (0.57) | 0.16 (0.34) | 0.29 (0.01)* | 0.31 (0.01)* |
| PLUNC | −0.13 (0.28) | −0.07 (0.56) | −0.08 (0.48) | −0.04 (0.71) |
| PSP94 | −0.17 (0.16) | −0.05 (0.71) | −0.21 (0.057) | −0.56 (0.62) |
Definition of abbreviations: α2-HS glycoprotein = α2-Heremans–Schmid glycoprotein; COPD 2 = stage II chronic obstructive pulmonary disease; PLUNC = palate, lung, and nasal epithelium clone protein; PSP94 = prostate secretory protein of 94 amino acids.
Analysis was performed using Kendall's tau b, comparing the quantity of each biomarker measured in sputum from healthy smokers and smokers with stage 2 COPD, with their corresponding FEV1 and FEV1/FVC values. Prebronchodilator lung function data were used for the comparison. Biomarker quantities were compared using raw values and also those normalized for protein content. Kendall's tau b values are shown, with P values in parentheses.
P < 0.05 (considered significant).