A total of 1264 patients (922 females and 342 males) were enrolled in the analysis, and the mean age was 49.4 (range: 18–78) years. There were 39 smokers and 35 drinkers. A total of 577 patients were classified as overweight, and 171 patients were classified as obese. The postoperative pathology was benign in 361 patients and malignant in 903 patients. The mean operation time was 1.6 (range: 0.7–4.8) hours. Postoperative bleeding occurred in 19 patients, transient hypocalcemia occurred in 186 patients, and vocal cord palsy occurred in 11 patients.
A total of 359 patients had postoperative cough, and the overall prevalence was 28.4%. In patients with cough, 6 developed postoperative bleeding, and in patients without cough, 13 developed postoperative bleeding; the difference was not significant (p = 0.747). In patients with benign disease, postoperative cough occurred in 62 patients with an prevalence rate of 17.2%, in these 62 patients, 2 (3.2%) patients had postoperative bleeding, 4 (6.5%) patients had transient hypocalcemia, and 1 (1.6%) patients had vocal cord palsy, in 299 patients without cough, 2 (0.7%) patients had postoperative bleeding, 20 (6.7%) patients had transient hypocalcemia, and 1 (0.3%) patients had vocal cord palsy, the mean operation time was 1.3 (range: 0.7–2.4) hours.
In patients with malignant disease, postoperative cough occurred in 297 patients with an prevalence rate of 32.9%, in these 297 patients, 4 (1.3%) patients had postoperative bleeding, 42 (14.1%) patients had transient hypocalcemia, and 1 (0.3%) patients had vocal cord palsy, in 606 patients without cough, 11 (1.8%) patients had postoperative bleeding, 120 (19.8%) patients had transient hypocalcemia, and 8 (1.3%) patients had vocal cord palsy, and the mean operation time was 1.7 (range: 0.8–4.8) hours.
The differences regarding cough occurrence and operation time between patients with benign disease and patients with malignant disease were both significant (both p < 0.001). There were no differences in age, sex, or BMI between the two groups (all p > 0.05).
To identify the risk factors for postoperative cough in patients with benign disease, as described in Table 1, in the univariate analysis, the factors of smoking, operation time, and operation extent were associated with the occurrence of postoperative cough (all p < 0.05). In further multivariate logistic regression analysis (Table 2), the factors of smoking and operation time were related to the occurrence of postoperative cough (all p < 0.05).
Table 1
Univariate analysis of risk factors for postoperative cough in patients with benign thyroid disease.
Variables | Univariate |
| Cough (n = 62) | No cough (n = 299) | |
Age ≥45 | 42 | 184 | |
༜45 | 20 | 115 | 0.358 |
Sex Female | 48 | 200 | |
Male | 14 | 99 | 0.104 |
Smoker No | 54 | 289 | |
Yes | 8 | 10 | 0.002 |
Drinker No | 57 | 289 | |
Yes | 5 | 10 | 0.090 |
Operation time ༜1.3 h | 40 | 234 | |
≥1.3 h | 22 | 65 | 0.021 |
BMI Normal | 27 | 103 | |
24 ~ 28 | 24 | 129 | |
>28 | 11 | 67 | 0.380 |
Operation extent Unilateral | 24 | 167 | |
Bilateral | 38 | 132 | 0.014 |
Table 2
Multivariate analysis of risk factors for postoperative cough in patients with benign thyroid disease.
Variables | Multivariate analysis |
| p | HR [95% CI] |
Smoker | 0.001 | 3.336 [1.542–7.886] |
Operation time | 0.008 | 1.896 [1.278–4.481] |
Operation extent | 0.475 | 2.772 [0.664–5.112] |
Table 3
Univariate analysis of risk factors for postoperative cough in patients with malignant thyroid disease.
Variables | Univariate |
| Cough (n = 297) | No cough (n = 606) | |
Age ≥45 | 190 | 367 | |
༜45 | 107 | 239 | 0.322 |
Sex Female | 214 | 460 | |
Male | 83 | 146 | 0.211 |
Smoker Yes | 12 | 9 | |
No | 285 | 597 | 0.017 |
Drinker Yes | 10 | 10 | |
No | 287 | 596 | 0.100 |
Operation time ≥1.3 h | 203 | 300 | |
༜1.3 h | 94 | 306 | < 0.001 |
BMI Normal | 116 | 270 | |
24 ~ 28 | 141 | 283 | |
>28 | 40 | 53 | 0.056 |
Operation extent Unilateral | 83 | 308 | |
Bilateral | 214 | 298 | < 0.001 |
Number of positive nodes in level 6 | | | |
≥3 | 118 | 195 | |
<3 | 179 | 511 | < 0.001 |
Lateral neck dissection | | | |
Yes | 99 | 256 | |
No | 198 | 350 | 0.010 |
Cancer type | | | |
PTC | 287 | 577 | |
others | 10 | 29 | 0.325 |
PTC: papillary carcinoma |
To identify the risk factors for postoperative cough in patients with malignant disease, as described in Table 2, in the univariate analysis, the factors of smoking, operation time, operation extent, the number of positive nodes at level 6, and lateral neck dissection were associated with the occurrence of postoperative cough (all p < 0.05). In further multivariate logistic regression analysis (Table 4), the factors of smoking, operation time, operation extent, and the number of positive nodes at level 6 were related to the occurrence of postoperative cough (all p < 0.05).
Table 4
Multivariate analysis of risk factors for postoperative cough in patients with malignant thyroid disease.
Variables | Multivariate analysis |
| p | HR [95% CI] |
Smoker | 0.003 | 4.004 [1.672–8.462] |
Operation time | 0.005 | 2.556 [1.448–5.132] |
Operation extent | 0.014 | 2.988 [1.264–4.874] |
Number of positive nodes in level 6 | < 0.001 | 5.654 [2.003–9.439] |
Lateral neck dissection | 0.087 | 2.432 [0.922–7.583] |
In coughing patients with benign disease, the mean preoperative LCQ score was 21, and the mean LCQ score was 18.8 (SD: 3.7) at the second week after the operation; the difference was significant (p < 0.001). The mean LCQ score was 20.9 (SD: 0.2) at the fourth week after the operation, and when compared to the preoperative level, the difference was not significant (p = 0.961).
In coughing patients with malignant disease, the mean preoperative LCQ score was 21, and the mean LCQ score was 16.8 (SD: 5.7) the second week after the operation; the difference was significant (p < 0.001). The mean LCQ score was 20.8 (SD: 0.3) the fourth week after the operation, and when compared to the preoperative level, the difference was not significant (p = 0.903).
When comparing the scores among different time periods in patients with benign or malignant disease, there was no significant difference between the two groups at the preoperative and postoperative 4-week time periods (both p > 0.05), but patients with malignant disease had significantly lower LCQ scores than patients with benign disease at the postoperative 2-week time period (p = 0.001).