Association of incidental emphysema with annual lung function decline and future development of airflow limitation

Figures & data

Table 1 Baseline characteristics at the initial visit

	Total	Emphysema (−)	Emphysema (+)	P-value
N	628	543	85
Age (years), median (Q1, Q3)	48 (40, 56)	48 (40, 56)	49 (42.5, 56)	0.16
Male sex	474 (75.5%)	403 (74.2%)	71 (83.5%)	0.08
Height (cm)	166.8±8.5	166.7±8.7	168.0±7.1	0.12
Body weight (kg)	67.1±10.9	66.8±10.9	69.0±10.3	0.10
BMI	24.0±3.0	24.0±2.9	24.4±3.3	0.21
Current smoker	271 (43.2%)	241 (44.4%)	30 (35.3%)	0.13
Noncurrent smoker
Ex-smoker	150 (23.9%)	121 (22.3%)	29 (34.1%)	0.71
Never smoker	207 (33.0%)	181 (33.3%)	26 (30.6%)
Pack years, median (Q1,Q3)	10.0 (0, 22.5)	10.0 (0, 22.5)	8.5 (0, 20)	0.87
FU duration (years)	3.1±1.4	3.1±1.4	3.2±1.4	0.87
PFT
FVC (L)	4.02±0.84	4.00±0.84	4.18±0.82	0.06
FVC (% predicted)	98.0±11.0	97.7±10.8	99.9±12.1	0.08
FEV1 (L)	3.26±0.69	3.24±0.68	3.38±0.70	0.09
FEV1 (% predicted)	105.7±12.4	105.3±12.5	107.9±12.2	0.08
FEV1/FVC (%)	81.2±5.5	81.3±5.5	80.7±5.5	0.37
%LAA−950, median (Q1, Q3)	1.8 (0.6, 7.0)	1.3 (0.5, 4.3)	13.3 (11.2, 17.3)	<0.001

Note: %LAA₋₉₅₀ is the percentage of low-attenuation area below −950 Hounsfield units measured by computed tomography quantification.

Abbreviations: N, Number; Q1, first quartile; Q3, third quartile; BMI, body mass index; FU, follow-up; PFT, pulmonary function test; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second.

Figure 1 Flowchart describing recruitment of study population.

Abbreviations: CT, computed tomography; PFT, pulmonary function test.

Table 2 Adjusted decline rate of lung function according to the presence of emphysema

Total*	FEV1				FVC				FEV1/FVC
	mL/yr	SE	Mean difference	P-value	mL/yr	SE	Mean difference	P-value	mL/yr	SE	Mean difference	P-value
Emphysema (−) (n=543)	−17.5	2.6	8.8 (−2.7, 20.3)	0.14	−18.8	2.4	15.2 (2.6, 27.8)	0.02	−0.45	0.05	0.12 (−0.2, 0.4)	0.35
Emphysema (+) (n=85)	−26.3	5.7			−33.9	6.0			−0.34	0.11

Note:

* Adjusted by age, sex, height, BMI, current smoking status, and baseline PFT.

Abbreviations: FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; yr, year; SE, standard error; BMI, body mass index; PFT, pulmonary function test.

Figure 2 Occurrence of airflow limitation rate during follow-up according to the presence of emphysema.