Table 1.
Baseline characteristics of the normal and low lymphocyte groups.
| Total (n = 451) | Normal lymphocytea (n = 409) | Low lymphocyteb (n = 42) | P value | |
|---|---|---|---|---|
| Sex, male | 437 (96.9) | 395 (96.6) | 42 (100) | 0.630 |
| Age, years | 67.5 ± 7.6 | 66.8 ± 7.3 | 66.6 ± 6.9 | 0.874 |
| Body mass index, kg/m2 | 22.9 ± 3.2 | 23.3 ± 3.2 | 21.6 ± 3.6 | 0.009 |
| Smoking status | 0.401 | |||
| Current smoker | 157 (34.8) | 145 (35.5) | 12 (28.6) | |
| Former smoker | 294 (65.2) | 264 (64.5) | 30 (71.4) | |
| Pulmonary function | ||||
| FEV1, L | 1.65 ± 0.56 | 1.69 ± 0.55 | 1.32 ± 0.55 | < 0.001 |
| FEV1, % predicted | 54.9 ± 16.2 | 55.7 ± 15.7 | 47.1 ± 19.1 | 0.001 |
| FVC, L | 3.50 ± 0.78 | 3.54 ± 0.78 | 3.12 ± 0.74 | 0.001 |
| FVC, % predicted | 90.4 ± 17.6 | 91.0 ± 17.2 | 84.9 ± 19.9 | 0.030 |
| FEV1/FVC, % | 47.1 ± 11.2 | 47.7 ± 11.0 | 41.6 ± 11.7 | 0.001 |
| GOLDc | 0.007 | |||
| GOLD I | 24 (5.3) | 22 (5.4) | 2 (4.8) | |
| GOLD II | 249 (55.3) | 234 (57.4) | 15 (35.7) | |
| GOLD III | 151 (33.6) | 134 (32.8) | 17 (40.5) | |
| GOLD IV | 26 (5.8) | 18 (4.4) | 8 (19.0) | |
| 6 MW distance, m | 422 ± 88 | 428 ± 85 | 360 ± 97 | < 0.001 |
| CAT Score | 13.8 ± 7.4 | 13.6 ± 7.3 | 15.8 ± 7.7 | 0.272 |
| SGRQ score | 32.2 ± 17.9 | 31.2 ± 17.5 | 41.9 ± 19.3 | < 0.001 |
| Number of exacerbation per year | 0.48 ± 0.79 | 0.46 ± 0.78 | 0.67 ± 0.85 | 0.100 |
| Follow-up duration, years | 6.0 ± 3.9 | 6.1 ± 3.9 | 4.9 ± 3.1 | 0.052 |
| Death during follow-up | 58 (12.9) | 46 (12.0) | 12 (28.6) | 0.006 |
Data are presented as numbers (percentages) or means ± standard deviation, unless otherwise indicated.
FEV1 forced expiratory volume in 1 s, FVC forced vital capacity, GOLD global initiative for chronic obstructive lung disease, 6 MW 6-min walking, CAT COPD assessment test, SGRQ St. George's respiratory questionnaire.
aNormal lymphocyte group was defined as those with serum lymphocyte percentage 20 to 51%.
bLow lymphocyte group was defined as those with serum lymphocyte percentage < 20%.
cP value for comparison between COPD patients with GOLD I–II and those with GOLD III–IV.