Spirometry is underused in the diagnosis and monitoring of patients with chronic obstructive pulmonary disease (COPD)

Figures & data

Figure 1 Subject screening and recruitment summary.

Abbreviations: post-BD, post-bronchodilator; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity.

Table 1 Subject characteristics according to whether spirometry was ever performed

Parameter	All (N = 120)	With spirometry (n = 64)	Without spirometry (n = 56)	P-value
Male:female	111:9	58:6	53:3
Male %	92.5%	90.6%	94.6%	0.500a
Age (mean, SD)	71.8 (8.02)	71.7 (7.04)	71.9 (8.82)	0.883b
Smoking status
Never (n, %)	6 (5%)	4 (6.3%)	2 (3.6%)	–
Ex- (n, %)	88 (73.3%)	48 (75.0%)	40 (71.4%)	–
Current (n, %)	26 (21.7%)	12 (18.8%)	14 (25%)	0.407c
Pack-year (mean, SD)	58.4 (37.90)	59.2 (36.46)	57.6 (39.45)	0.226d
Worker occupation (n, %)	70 (58.3)	38 (59.4)	32 (57.1%)	0.805c
With old PTB (n, %)	20 (16.7%)	5 (7.8%)	15 (26.8%)	0.005c
Significant medical comorbiditye
At least one (n, %)	72 (60.0%)	38 (59.4%)	34 (60.7%)	0.881c
Duration of COPD in years (mean, SD)	9.8 (7.55)	9.6 (6.18)	10.1 (8.86)	0.431d
Post-BD FEV1 percentage predicted (mean, SD)	46.2 (19.89)	41.0 (17.57)	52.1 (20.72)	0.002d
Post-BD FVC percentage predicted (mean, SD)	71.7 (22.86)	66.6 (20.62)	77.5 (24.07)	0.027d
Peak expiratory ratio (FEV1/FVC) (mean, SD)	0.476 (0.131)	0.455 (0.126)	0.499 (0.133)	0.067d
FEV1 bronchodilator reversibility (mean, SD)
Volume change (mL)	122.5 (124.1)	104.8 (113.9)	142.7 (133.0)	0.145d
Percentage change	5.5 (5.5)	4.8 (5.0)	6.4 (5.9)	0.137d
GOLD stage (n, % of stage group, 95% CI)				0.003a
Stage I	10	2 (20%, −4.8%–44.8%)	8 (80%)
Stage II	38	15 (39.5%, 24%–55%)	23 (60.5%)
Stage III	46	27 (58.7%, 44.5%–72.9%)	19 (41.3%)
Stage IV	26	20 (76.9%, 60.7%–93.1%)	6 (23.1%)
BMI (mean, SD)	22.2 (3.84)	22.4 (3.56)	22.1 (4.13)	0.479d
6 MWD in meters (mean, SD)	253.7 (77.20)	256.7 (77.53)	250.2 (76.68)	0.650b
MRC dyspnea score (median, IQR)	2 (1)	2 (1)	2 (1)	0.941d
Clinic location
Respiratory specialist clinic (group 1)	30	29 (96.7%)	1 (3.3%)	0.000c
Medical specialist clinics (group 2)	30	20 (66.7%)	10 (33.3%)
Primary care clinics (group 3)	30	8 (26.7%)	22 (73.3%)
Tuberculosis and chest clinic (group 4)	30	7 (23.3%)	23 (76.7%)
Groups 2 + 3 + 4	90	35 (38.9%)	55 (61.1%)

Notes:

a Fisher’s exact test;

b independent-samples t-test;

c chi-square test;

d Mann–Whitney U-test;

e significant medical comorbidity includes hypertension, ischemic heart disease, congestive heart failure, cardiac arrhythmia, cerebrovascular disease, diabetes mellitus with or without complications, chronic liver disease, chronic renal disease, obstructive sleep apnea, rheumatoid arthritis, tumors, malignancies, depression, and schizophrenia.

Abbreviations: SD, standard deviation; PTB, pulmonary tuberculosis; COPD, chronic obstructive pulmonary disease; post-BD, post-bronchodilator; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease; BMI, body mass index; 6 MWD, 6-minute walking distance; MRC, Medical Research Council; CI, confidence interval; IQR, interquartile range.

Table 2 Factors associated with spirometry ever done – multivariate analysis (logistic regression by backward elimination)

	Adjusted odds ratio	95% CI	P-value
With old pulmonary tuberculosis	0.138	(0.026–0.726)	0.019
Clinic location (compared with group 1)
Group 2	0.049	(0.005–0.472)	0.009
Group 3	0.009	(0.001–0.092)	0.000
Group 4	0.008	(0.001–0.080)	0.000
GOLD stage (compared with stage I)			NS
Post-BD FEV1 percentage predicted			NS
Post-BD FVC percentage predicted			NS
Peak expiratory ratio (FEV1/FVC)			NS
FEV1 bronchodilator reversibility change (mL)			NS
FEV1 bronchodilator reversibility change (%)			NS

Abbreviations: CI, confidence interval; GOLD, Global Initiative for Chronic Obstructive Lung Disease; post-BD, post-bronchodilator; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; NS, non significant.

Table 3 Comparison of use of spirometry and chest radiograph

	Spirometry	Chest radiograph	P-value
Done at diagnosis	22 (18.3%)	96 (80%)	0.000a
Done ever	64 (53.3%)	117 (97.5%)	0.000a
Mean time before study visit (months)	39.1	12.1	0.000b
Range (months)	1–132	0.5–84.0	NA

Notes:

a Mcnemar’s test;

b t-test for two related samples; NA, not applicable.

Figure 2 Timeframe of performing spirometry according to groups.