Table 2.
Statistical Correlations Between Plasma Metabolites and COPD
| Non-COPD (n=80) | COPD (n=120) | *p-value of t-test | Linear Regression | ||||
|---|---|---|---|---|---|---|---|
| LSmean | SD | LSmean | SD | beta | *p-value | ||
| Ceramides (nM) | |||||||
| C14 | 2.70 | 0.05 | 2.78 | 0.05 | 0.3411 | 0.084 | 0.3411 |
| C16 | 5.61 | 0.04 | 5.61 | 0.03 | 0.8987 | 0.008 | 0.8987 |
| C18 | 4.80 | 0.07 | 4.76 | 0.05 | 0.7525 | 0.033 | 0.7525 |
| C18_1 | 3.03 | 0.06 | 3.00 | 0.05 | 0.7956 | 0.023 | 0.7956 |
| C20 | 4.91 | 0.07 | 4.94 | 0.05 | 0.7681 | 0.028 | 0.7681 |
| C24 | 7.92 | 0.06 | 7.96 | 0.05 | 0.6808 | 0.037 | 0.6808 |
| C24_1 | 7.09 | 0.06 | 7.05 | 0.05 | 0.6547 | 0.040 | 0.6547 |
| SM18_0 | 9.46 | 0.05 | 9.53 | 0.04 | 0.3057 | 0.076 | 0.3057 |
| SM18_1 | 8.70 | 0.05 | 8.76 | 0.04 | 0.4468 | 0.054 | 0.4468 |
| SM16_0 | 11.10 | 0.04 | 11.18 | 0.03 | 0.1743 | 0.079 | 0.1743 |
| SM24_0 | 9.72 | 0.06 | 9.90 | 0.04 | 0.0357 | 0.177 | 0.0357 |
| SM24_1 | 10.51 | 0.05 | 10.60 | 0.04 | 0.0265 | 0.086 | 0.0265 |
| Amino acids (μM) | |||||||
| Glycine | 4.68 | 0.10 | 4.73 | 0.07 | 0.7166 | −0.050 | 0.7166 |
| Alanine | 6.05 | 0.09 | 5.97 | 0.07 | 0.5640 | −0.078 | 0.5640 |
| Serine | 4.12 | 0.09 | 4.12 | 0.07 | 0.9783 | −0.003 | 0.9783 |
| Proline | 3.68 | 0.09 | 3.62 | 0.07 | 0.6830 | −0.055 | 0.6830 |
| Valine | 7.43 | 0.06 | 7.29 | 0.04 | 0.0894 | −0.139 | 0.0894 |
| Threonine | 4.32 | 0.09 | 4.26 | 0.07 | 0.6767 | −0.055 | 0.6767 |
| Taurine | 2.99 | 0.10 | 3.01 | 0.07 | 0.8997 | 0.017 | 0.8997 |
| t4_OH_Pro | 1.27 | 0.14 | 1.00 | 0.10 | 0.1722 | −0.268 | 0.1722 |
| Leucine | 6.26 | 0.06 | 6.12 | 0.05 | 0.1158 | −0.146 | 0.1158 |
| Isoleucine | 5.27 | 0.07 | 5.09 | 0.05 | 0.0701 | −0.172 | 0.0701 |
| Asparagine | 3.66 | 0.09 | 3.62 | 0.07 | 0.7211 | −0.045 | 0.7211 |
| Aspartate | 2.74 | 0.11 | 2.77 | 0.08 | 0.8780 | −0.023 | 0.8780 |
| Glutamine | 5.92 | 0.08 | 5.92 | 0.06 | 0.9854 | 0.002 | 0.9854 |
| Glutamate | 4.69 | 0.11 | 4.70 | 0.08 | 0.9693 | 0.006 | 0.9693 |
| Methionine | 7.11 | 0.13 | 6.87 | 0.10 | 0.2158 | −0.238 | 0.2158 |
| Histidine | 2.72 | 0.09 | 2.85 | 0.07 | 0.2937 | 0.134 | 0.2937 |
| Alpha_AAA | 0.84 | 0.11 | 0.83 | 0.08 | 0.9415 | 0.012 | 0.9415 |
| Phenylalanine | 4.05 | 0.05 | 3.97 | 0.04 | 0.3114 | −0.074 | 0.3114 |
| Arginine | 2.93 | 0.10 | 3.00 | 0.07 | 0.6114 | 0.072 | 0.6114 |
| Ac_Orn | −0.23 | 0.12 | 0.11 | 0.09 | 0.0552 | 0.338 | 0.0552 |
| Citrulline | 4.00 | 0.10 | 4.09 | 0.08 | 0.5656 | 0.085 | 0.5656 |
| Tyrosine | 3.35 | 0.09 | 3.33 | 0.06 | 0.8644 | −0.021 | 0.8644 |
| ADMA | −1.70 | 0.09 | −1.54 | 0.06 | 0.1981 | 0.160 | 0.1981 |
| SDMA | −1.33 | 0.10 | −1.18 | 0.07 | 0.2771 | 0.149 | 0.2771 |
| Tryptophan | 4.54 | 0.06 | 4.48 | 0.04 | 0.4283 | −0.069 | 0.4283 |
| Kynurenine | 1.01 | 0.08 | 1.05 | 0.06 | 0.7455 | 0.039 | 0.7455 |
| Ornithine | 5.39 | 0.07 | 5.17 | 0.05 | 0.0251 | −0.229 | 0.0251 |
| Met_SO | 6.80 | 0.06 | 6.67 | 0.04 | 0.1056 | −0.129 | 0.1056 |
Notes: *This p-value was used for the Student’s t-test and chi-square test for the analyses of the non-COPD and COPD groups followed by linear regression analysis, respectively. Here, bold values indicates a statistically significant correlation with a p-value less than 0.05. The data was adjusted for age, smoking, pack years, BMI, Gold grade, drug history, and CCI and then analyzed using log transformation.