Difference in systemic inflammation and predictors of acute exacerbation between smoking-associated COPD and tuberculosis-associated COPD

Figures & data

Table 1 Baseline characteristics of patients with S-COPD and T-COPD

	S-COPD (N=78)	T-COPD (N=92)	P-value
Age, years	66.0 (59.0–72.5)	67.0 (63.0–71.8)	0.261
Sex, male	72 (92.3)	61 (66.3)	<0.001
BMI, kg/m^2	23.6 (21.1–26.0)	23.5 (21.6–25.5)	0.605
Smoking status
Never	9 (11.5)	43 (46.7)	<0.001
Former	35 (44.9)	35 (38.0)
Current	34 (43.6)	14 (15.2)
Smoking amount (pack-year)	40.0 (20.0–45.3)	0.0 (0.0–30.0)	<0.001
Comorbidities
DM	3 (3.8)	9 (9.8)	0.132
CVD	9 (11.5)	8 (8.7)	0.538
Heart disease	31 (39.7)	34 (37.0)	0.709
GERD	6 (7.7)	4 (4.3)	0.356
Depression	2 (2.6)	4 (4.3)	0.530

Note: Data are presented as median (IQR) for continuous variables and number (percentage) for categorical variables.

Abbreviations: BMI, body mass index; CVD, cerebrovascular disease; DM, diabetes mellitus; GERD, gastroesophageal reflux disease; S-COPD, smoking-associated COPD; TOPD, tuberculosis-associated COPD.

Table 2 Pulmonary function tests, symptom scores, and outcomes of patients with COPD and TOPD

	S-COPD (N=78)	T-COPD (N=92)	P-value
Pulmonary function tests
FEV1 %	64.5 (46.8–71.0)	57.5 (45.0–72.5)	0.717
FVC %	84.5 (74.8–93.3)	77.0 (64.3–88.0)	0.003
FEV1/FVC %	55.0 (41.0–62.0)	56.5 (45.3–66.0)	0.080
FEF 25%–75%	23.5 (16.0–34.5)	23.0 (16.0–37.8)	0.999
VC %	93.0 (82.0–103.0)	86.0 (72.0–99.5)	0.007
TLC %	107.5 (102.8–116.0)	103.5 (91.3–112.8)	0.005
IC %	74.5 (58.8–93.3)	65.5 (53.0–86.0)	0.066
FRC %	140.0 (123.8–160.5)	130.5 (109.3–148.5)	0.011
RV %	142.0 (130.0–155.5)	143.5 (118.8–154.0)	0.547
DLCO%	80.5 (65.8–95.3)	75.5 (62.0–89.0)	0.187
Symptom scores
mMRC	1.0 (0.0–1.0)	1.0 (0.0–1.0)	0.216
CAT	14.0 (10.0–19.0)	16.0 (10.0–21.0)	0.116
SGRQ	17.5 (9.3–29.7)	22.5 (14.5–33.0)	0.029
FEV1 decline mL/year	10.5 (−48.5 to −170.0)	50.0 (−17.5 to −140.0)	0.323
AE	26 (33.3)	33 (35.9)	0.729

Note: Data are presented as median (IQR) for continuous variables and number (percentage) for categorical variables.

Abbreviations: AE, acute exacerbation; CAT, COPD assessment test; DL_CO, diffusing capacity of the lung for carbon monoxide; FEF FRC, functional residual capacity; FEF 25%–75%, forced expiratory flow at 25%–75% of FVC; IC, inspiratory capacity; mMRC, modified Medical Research Council; RV, residual volume; S-COPD, smoking-associated COPD; SGRQ, St George Respiratory Questionnaire; TLC, total lung capacity; TOPD, tuberculosis-associated chronic obstructive disease; VC, vital capacity.

Figure 1 Comparison of inflammatory biomarkers in patients with S-COPD and T-COPD.

Notes: (A) C-reactive protein in patients with S-COPD and T-COPD (P<0.001). (B) Erythrocyte sedimentation rate in patients with S-COPD and T-COPD (P=0.002). (C) IL-6 in patients with S-COPD and T-COPD (P<0.001).
Abbreviations: CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; S-COPD, smoking-associated COPD; T-COPD, tuberculosis-associated COPD.

Table 3 Parameters associated with acute exacerbation in patients with S-COPD

Characteristics	Univariate analysis		Multivariate analysis*
	OR (95% CI)	P-value	OR (95% CI)	P-value
Age	0.998 (0.948–1.051)	0.947	–	–
Gender (male)	0.469 (0.088–2.507)	0.376
BMI	0.945 (0.831–1.075)	0.392	–	–
Smoking amount	1.003 (0.984–1.023)	0.762	–	–
FEV1	0.930 (0.897–0.964)	<0.001	0.941 (0.901–0.983)	0.006
CAT	1.040 (0.967–1.118)	0.294	–	–
SGRQ	1.046 (1.011–1.082)	0.010	1.026 (0.987–1.065)	0.194
CRP	1.016 (0.950–1.087)	0.634	–	–
IL-6	1.595 (1.137–2.239)	0.007	1.407 (0.950–2.083)	0.088

Note:

* Variables with a P-value <0.1 on univariate analysis were analyzed using multivariate logistic regression analysis.

Abbreviations: BMI, body mass index; CAT, COPD assessment test; CRP, C-reactive protein; S-COPD, smoking-associated COPD; SGRQ, St George Respiratory Questionnaire.

Table 4 Parameters associated with acute exacerbation in patients with T-COPD

Characteristics	Univariate analysis		Multivariate analysis*
	OR (95% CI)	P-value	OR (95% CI)	P-value
Age	0.992 (0.934–1.053)	0.795	–	–
Gender (male)	0.975 (0.395–2.404)	0.956	–	–
BMI	1.066 (0.921–1.229)	0.383	–	–
Smoking amount	0.998 (0.981–1.016)	0.831	–	–
FEV1	0.979 (0.955–1.003)	0.084	0.994 (0.962–1.027)	0.994
CAT	1.091 (1.001–1.189)	0.047	1.048 (0.973–1.129)	0.212
SGRQ	1.024 (1.000–1.048)	0.054	1.013 (0.987–1.040)	0.339
CRP	1.110 (1.000–1.231)	0.049	1.005 (0.919–1.100)	0.905
IL-6	1.148 (1.047–1.259)	0.003	1.109 (1.004–1.225)	0.041

Note:

* Variables with a P-value <0.1 on univariate analysis were analyzed using multivariate logistic regression analysis.

Abbreviations: BMI, body mass index; CAT, COPD assessment test; CRP, C-reactive protein; SGRQ, St George Respiratory Questionnaire; T-COPD, tuberculosis-associated COPD.

Figure 2 Receiver-operating-characteristic curve of IL-6 as a predictor of acute exacerbation in T-COPD.

Note: IL-6 >2.04 pg/mL was a cutoff for predicting exacerbation of T-COPD (sensitivity 84.8%, specificity 59.3%, P<0.001).
Abbreviation: T-COPD, tuberculosis-associated COPD.