Risk of incident chronic obstructive pulmonary disease during longitudinal follow-up in patients with nontuberculous mycobacterial pulmonary disease

Table 2 Result of pulmonary function test in the study population

Variables	Total (n = 91,803)	Control group (n = 90,088)	NTM-PD group (n = 1,715)	p	Matched control group (n = 6,860)	NTM-PD group (n = 1,715)	p
Interval between baseline and follow-up spirometry tests, years	3.3 ± 3.0	3.3 ± 3.0	3.3 ± 2.6	0.394	3.2 ± 2.7	3.3 ± 2.6	0.053
Baseline spirometry
FVC, L	3.8 ± 0.8	3.8 ± 0.8	3.3 ± 0.8	< 0.001	3.2 ± 0.7	3.3 ± 0.8	0.011
FVC, % predicted	94.9 ± 10.9	95.0 ± 10.8	92.7 ± 12.2	< 0.001	95.5 ± 12.2	92.7 ± 12.2	< 0.001
FEV₁, L	3.2 ± 0.7	3.2 ± 0.7	2.6 ± 0.6	< 0.001	2.7 ± 0.6	2.6 ± 0.6	0.017
FEV₁, % predicted	102.3 ± 13.5	102.4 ± 13.4	97.5 ± 12.9	< 0.001	105.4 ± 15.0	97.5 ± 12.9	< 0.001
FEV₁/FVC (%)	82.9 ± 5.5	83.0 ± 5.4	79.0 ± 6.3	< 0.001	81.4 ± 5.8	79.0 ± 6.3	< 0.001
Follow-up spirometry
FVC, L	3.7 ± 0.8	3.8 ± 0.8	3.1 ± 0.8	< 0.001	3.2 ± 0.7	3.1 ± 0.8	0.001
FVC, % predicted	93.8 ± 11.5	93.9 ± 11.3	86.3 ± 14.6	< 0.001	93.6 ± 13.7	86.3 ± 14.6	< 0.001
FEV₁, L	3.0 ± 0.7	3.0 ± 0.7	2.4 ± 0.6	< 0.001	2.5 ± 0.6	2.4 ± 0.6	< 0.001
FEV₁, % predicted	99.10 ± 14.3	99.1 ± 14.2	88.2 ± 15.2	< 0.001	98.5 ± 17.3	88.2 ± 15.2	< 0.001
FEV₁/FVC (%)	81.1 ± 6.3	81.2 ± 6.3	77.2 ± 8.5	< 0.001	79.0 ± 7.1	77.2 ± 8.5	< 0.001
COPD development	2,272 (2.5)	2,031 (2.3)	241 (14.0)	< 0.001	293 (4.3)	241 (14.0)	< 0.001
Change in lung function
FEV₁ decline, mL/year	38.4 ± 132.9	37.7 ± 131.8	77.6 ± 176.0	< 0.001	47.3 ± 126.6	77.6 ± 176.0	< 0.001
Rapid FEV₁ decline^*	34,794 (37.9)	34,017 (37.8)	777 (45.3)	< 0.001	2,598 (37.9)	777 (45.3)	< 0.001

Data are expressed as mean ± standard deviation or number (%)
^*Decline in FEV₁ > 60 mL/year is defined as a rapid FEV₁ decline
Abbreviations: NTM-PD, nontuberculous mycobacterial pulmonary disease; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 s; COPD, chronic obstructive pulmonary disease

ISSN: 1465-993X