Table 3 EBC pH values according to RV/TLC quartiles in our study population
From: Exhaled breath condensate pH as a biomarker of COPD severity in ex-smokers
| Â | Â | 1stQuartile | 2ndQuartile | 3rdQuartile | 4thQuartile | p-value |
|---|---|---|---|---|---|---|
COPD all | RV/TLC | ≤0.50 | 0.50-0.58 | 0.58-0.66 | >0.66 |  |
| Â | EBC pH | 7.52 (6.88, 8.01) | 7.19 (6.69, 7.69) | 7.27 (7.08, 7.78) | 6.93 (5.46, 7.19)# | <0.001 |
COPD ex-smokers | RV/TLC | ≤0.52 | 0.52-0.60 | 0.60-0.68 | >0.68 |  |
|  | EBC pH | 7.64 (6.88, 7.91) | 7.10 (6.68, 7.45) | 7.27 (7.08, 7.64) | 6.92 (5.79, 7.07) †| 0.006 |
COPD current smokers | RV/TLC | ≤0.47 | 0.47-0.55 | 0.55-0.63 | >0.63 |  |
| Â | EBC pH | 7.48 (7.06, 8.03) | 7.36 (6.71, 7.95) | 7.23 (6.47, 7.88) | 7.13 (5.36, 7.84) | 0.398 |