Table 3. Results of logistic regression model to predict postoperative pulmonary complications (PPC) and assigned points based on regression coefficient to develop the PPC scoring index.
| Univariable analysis | Multivariable analysis | |||||||
| Variables | With PPC (n = 140) | Without PPC (n = 1919) | OR (95% CI) | p | Regression coefficient | OR (95% CI) | p | Assigned points |
| Age ≥70 yr | 82 (59) | 822 (43) | 1.89 (1.33–2.67) | <0.001 | 0.708 | 2.03 (1.37–3.00) | <0.001 | 2 |
| Sex, male | 102 (73) | 1186 (62) | 1.66 (1.13–2.44) | 0.010 | ||||
| Body mass index | ||||||||
| <18.5 kg/m2 | 12 (9) | 114 (6) | 1.40 (0.68–2.89) | 0.594 | ||||
| 18.5–25.0 kg/m2 | 87 (62) | 1158 (60) | 1.00 | Ref | ||||
| >25.0 kg/m2 | 41 (29) | 647 (34) | 0.84 (0.54–1.31) | 0.768 | ||||
| Current smoker within 2 months | 33 (24) | 267 (14) | 1.91 (1.27–2.88) | 0.002 | 0.482 | 1.62 (1.03–2.54) | 0.036 | 1 |
| Alcoholics | 4 (3) | 73 (4) | 0.75 (0.27–2.08) | 0.580 | ||||
| Malignancy | 78 (56) | 766 (40) | 1.89 (1.34–2.68) | <0.001 | ||||
| CHF | 7 (5) | 78 (4) | 1.24 (0.56–2.75) | 0.592 | ||||
| Confused mentality | 2 (1) | 33 (2) | 0.83 (0.20–3.49) | 0.797 | ||||
| Recent loss of body weight | 11 (8) | 65 (3) | 2.44 (1.26–4.73) | 0.009 | ||||
| ASA physical status ≥ class 2 | 109 (78) | 1201 (63) | 2.10 (1.40–3.17) | <0.001 | 0.466 | 1.59 (1.01–2.52) | 0.046 | 1 |
| Presence of airflow limitation | 68 (49) | 545 (28) | 2.38 (1.69–3.37) | <0.001 | 0.558 | 1.75 (1.18–2.58) | 0.005 | 1 |
| Serum albumin <4.0 g/dl | 61 (44) | 547 (29) | 1.95 (1.37–2.77) | <0.001 | 0.398 | 1.49 (1.00–2.21) | 0.049 | 1 |
| Serum hemoglobin <10 g/dl | 16 (11) | 129 (7) | 1.79 (1.03–3.10) | 0.039 | ||||
| Active lesion on chest radiography | 18 (13) | 192 (10) | 1.33 (0.79–2.22) | 0.284 | ||||
| General anesthesia | 129 (92) | 1640 (85) | 2.00 (1.06–3.74) | 0.031 | ||||
| Emergency surgery | 10 (7) | 74 (4) | 1.92 (0.97–3.80) | 0.062 | 0.768 | 2.16 (1.00–4.65) | 0.050 | 2 |
| Surgical specialty | ||||||||
| Others | 32 (23) | 969 (50) | 1.00 | Ref | 1.00 | |||
| Cardiac/aortic aneurysm repair/abdominal open surgery | 89 (64) | 415 (22) | 6.49 (3.89–10.85) | <0.001 | 1.949 | 7.02 (4.04–12.19) | <0.001 | 4 |
| Laparoscopic abdominal | 12 (9) | 219 (11) | 1.66 (0.72–3.81) | 0.432 | 0.551 | 1.74 (0.74–4.09) | 0.369 | |
| Neurosurgery | 7 (5) | 316 (16) | 0.67 (0.24–1.84) | 1.000 | −0.268 | 0.77 (0.25–2.30) | 1.000 | |
A multivariable analysis using a logistic regression model was conducted with backward step-wise selection with p<0.05 for inclusion of variables and p>0.10 for removal of variables from all variables used for Univariable analysis and only significant variables in a multivariable analysis were indicated in the table.
PPC, postoperative pulmonary complications; OR, odds ratio; CI, confidence interval; CHF, congestive heart failure; ASA, American Society of Anesthesiologists.
Hosmer-Lemeshow test, χ2 = 7.653, p = 0.468.