Table 2 Baseline characteristics of 511 diabetic patients with chronic obstructive pulmonary disease, stratified by metformin use
Characteristic | Total | Metformin | Non-metformin | P value |
|---|---|---|---|---|
N = 511 | N = 282 | N = 229 | ||
Age, years | 73.0 ± 9.4 | 72.1 ± 9.3 | 74.0 ± 9.3 | 0.025 |
  ≥ 65 | 407 (80) | 211 (75) | 196 (86) | 0.003 |
Male gender | 419 (82) | 232 (82) | 187 (82) | 0.858 |
BMI (N = 482; 266; 216) | 24.6 ± 4.3 | 24.8 ± 4.4 | 24.4 ± 4.1 | 0.251 |
  < 18.5 | 31 (6.4) | 17 (6.4) | 14 (6.5) | 0.712 |
 18.5–24 | 198 (41) | 105 (40) | 93 (43) |  |
  > 24 | 253 (53) | 144 (54) | 109 (51) |  |
GOLD stage | ||||
 1 | 139 (27) | 88 (31) | 51 (22) | 0.110 |
 2 | 242 (47) | 127 (45) | 115 (50) |  |
 3 | 115 (23) | 61 (22) | 54 (24) |  |
 4 | 15 (2.9) | 6 (2.1) | 9 (3.9) |  |
Comorbidity | ||||
 Hypertension | 309 (61) | 165 (59) | 144 (63) | 0.315 |
 Cerebrovascular disease | 56 (11) | 29 (10) | 27 (12) | 0.588 |
 Heart failure | 72 (14) | 22 (7.8) | 50 (22) | < 0.001 |
 Coronary artery disease | 164 (32) | 84 (30) | 80 (35) | 0.215 |
 Malignancy | 92 (18) | 42 (15) | 50 (22) | 0.042 |
Hospitalization, No.a | 0.04 ± 0.22 | 0.03 ± 0.17 | 0.06 ± 0.27 | 0.113 |
  ≥ 1 | 20 (3.9) | 8 (2.8) | 12 (5.2) | 0.164 |
HbA1c, % (N = 494; 275; 219) | 7.1 ± 1.1 | 7.1 ± 1.1 | 7.1 ± 1.2 | 0.972 |
Antidiabetic class, No. | ||||
  < 2 | 401 (79) | 192 (68) | 209 (91) | < 0.001 |
  ≥ 2 | 110 (22) | 90 (32) | 20 (8.7) |  |