Real-world characterization and differentiation of the Global Initiative for Chronic Obstructive Lung Disease strategy classification

Figures & data

Table 1 Physician-reported patient characteristics (n=1,659 unless otherwise stated)

Patient characteristics	Category	n (%) or mean (SD)
Sex	M	1,122 (67.63)
	F	537 (32.37)
Age in years		65.14 (10.44)
Ethnicity (1,644 patients)	White/Caucasian	1,517 (91.4)
BMI (1,594 patients)	kg · m^−2	26.77 (4.93)
Smoking status	Current smokers	533 (32.13)
	Ex-smokers	1,126 (67.87)
Lung function (FEV1) (1,073 patients)	FEV1 < 30	45 (4.19)
	FEV1 ≥ 30, FEV1 < 50	203 (18.92)
	FEV1≥50, FEV1<80	713 (66.45)
	FEV1 ≥ 80	112 (10.44)
COPD comanaged (more than one doctor), (1,645 patients)		685 (41.29)
How quickly disease is progressing (1,631 patients)	Slowly/average	1,542 (92.95)
	Rapid	89 (5.36)
Deyo–Charlson comorbidity index (CCI)a (1,528 patients)		1.40 (0.74)

Notes:

a Comorbid conditions as described by Deyo–Charlston index¹⁹ are mapped from as many as ten reported ICD-9-CM secondary diagnosis codes. A single summary cumulative value is represented. A score of 0 represents no comorbidities. Since COPD was a prerequisite in this research, minimum score was 1. Out of the 17 conditions, this research could accommodate 12: myocardial infarction, congestive heart failure, peripheral vascular disease, dementia, diabetes mellitus, cerebrovascular disease, COPD, connective tissue disease, mild liver disease, any malignancy including lymphoma and leukemia, AIDS, metastatic solid tumor.

Abbreviations: AIDS, acquired immunodeficiency syndrome; BMI, body mass index; COPD, chronic obstructive pulmonary disease; F, female; FEV₁, forced expiratory volume in 1 second; ICD-9-CM, international classification of disease, ninth revision, clinical modification; M, male; SD, standard deviation.

Table 2 Patient-reported patient COPD characteristics (n=1,659 unless otherwise stated)

Questions	Description	n (%) or mean (SD)
Breathing symptoms present in last 4 weeks, (1,514 patients)	Coughing up mucus and phlegm	649 (39.12)
	General tightness in chest	340 (20.49)
	Cough	878 (52.92)
Breathing condition’s effect on daily activities in past week: (1,631 patients)	0 No effect on daily activities	127 (7.66)
	1	194 (11.69)
	2	232 (13.98)
	3	262 (15.79)
	4	185 (11.15)
	5	130 (7.84)
	6	151 (9.10)
	7	124 (7.47)
	8	134 (8.08)
	9	55 (3.32)
	10 Condition prevented daily activities	37 (2.23)
Extent breathing condition has restricted normal life: (1,625 patients)	1 Not at all restricted	226 (13.62)
	2	460 (27.73)
	3	482 (29.05)
	4	353 (21.28)
	5 Completely restricted	104 (6.27)
Do you ever experience the following feelings, (1,623 patients)	Constant lack of energy	588 (35.44)
	Tiredness through lack of sleep	476 (28.69)
Impact breathing condition has on getting up and ready for the day: (1,634 patients)	1 No impact	413 (24.89)
	2	412 (24.83)
	3	268 (16.15)
	4	201 (12.12)
	5	167 (10.07)
	6	103 (6.21)
	7 Constant impact	70 (4.22)
Jenkins sleep scale (1,588 patients)	(scale 0–20, where 0= no problems with sleep and 20= high impact on sleep),	5.12 (4.65)

Abbreviations: COPD, chronic obstructive pulmonary disease; SD, standard deviation.

Table 3 ROC curves analysis and kappa statistic analysis

Cut point	ROC Points			Kappa statistic (95% CI)
	Sensitivity (%)	Specificity (%)	Youden index (bootstrap 95% CI)
≥0	100.00	0.00
≥1	100.00	0.65	0.01 (0.00–0.01)	0.00 (0.00–0.01)
≥2	100.00	1.47	0.01 (0.01–0.02)	0.01 (0.01–0.02)
≥3	100.00	2.40	0.02 (0.01–0.03)	0.02 (0.01–0.02)
≥4	100.00	3.96	0.04 (0.03–0.05)	0.03 (0.02–0.04)
≥5	100.00	5.53	0.06 (0.04–0.07)	0.04 (0.03–0.05)
≥6	100.00	7.00	0.07 (0.06–0.08)	0.05 (0.04–0.06)
≥7	99.83	9.12	0.09 (0.07–0.11)	0.06 (0.05–0.07)
≥8	99.83	10.97	0.11 (0.09–0.13)	0.08 (0.06–0.09)
≥9	99.83	15.21	0.15 (0.13–0.17)	0.11 (0.09–0.13)
≥10	99.48	18.25	0.18 (0.15–0.20)	0.13 (0.11–0.15)
≥11	98.95	22.95	0.22 (0.19–0.24)	0.16 (0.14–0.19)
≥12	98.61	27.93	0.27 (0.24–0.29)	0.20 (0.18–0.23)
≥13	97.91	32.26	0.30 (0.27–0.33)	0.23 (0.21–0.26)
≥14	96.86	35.67	0.33 (0.30–0.36)	0.25 (0.22–0.29)
≥15	95.99	39.54	0.36 (0.32–0.38)	0.28 (0.25–0.31)
≥16	94.60	42.49	0.37 (0.34–0.41)	0.30 (0.27–0.33)
≥17	93.38	47.28	0.41 (0.37–0.44)	0.33 (0.30–0.39)
≥18	90.07	50.14	0.40 (0.36–0.44)	0.34 (0.30–0.37)
≥19	88.15	54.84	0.43 (0.39–0.47)	0.37 (0.33–0.40)
≥20	86.06	58.53	0.45 (0.41–0.49)	0.39 (0.35–0.43)
≥21	81.71	62.49	0.44 (0.40–0.48)	0.39 (0.35–0.43)
≥22	78.40	67.56	0.46 (0.42–0.50)	0.42 (0.38–0.46)
≥23	73.34	71.61	0.45 (0.40–0.50)	0.42 (0.42–0.38)
≥24	70.38	76.13	0.47 (0.42–0.51)	0.45 (0.40–0.49)
≥25	64.46	80.00	0.44 (0.40–0.49)	0.44 (0.40–0.49)
≥26	59.93	84.06	0.44 (0.40–0.49)	0.45 (0.40–0.50)
≥27	53.48	87.83	0.41 (0.36–0.46)	0.44 (0.40–0.48)
≥28	46.86	91.34	0.38 (0.34–0.42)	0.42 (0.37–0.46)
≥29	39.20	94.01	0.33 (0.29–0.38)	0.38 (0.33–0.42)
≥30	33.97	96.13	0.30 (0.26–0.34)	0.35 (0.30–0.39)
≥31	29.27	97.70	0.27 (0.23–0.30)	0.32 (0.28–0.36)
≥32	25.09	98.43	0.24 (0.20–0.27)	0.28 (0.24–0.32)
≥33	19.34	99.26	0.19 (0.15–0.22)	0.23 (0.19–0.27)
≥34	15.51	99.63	0.15 (0.12–0.18)	0.19 (0.15–0.22)
≥35	11.32	99.83	0.11 (0.09–0.14)	0.14 (0.11–0.17)
≥36	7.49	99.83	0.07 (0.05–0.09)	0.09 (0.07–0.12)
≥37	5.57	99.83	0.05 (0.03–0.07)	0.07 (0.05–0.09)
≥38	3.83	99.91	0.04 (0.02–0.05)	0.05 (0.02–0.07)
≥39	2.79	99.91	0.02 (0.01–0.04)	0.03 (0.02–0.05)
≥40	1.39	99.91	0.01 (0.00–0.02)	0.02 (0.00–0.03)
≥41	0.00	100.00

Notes: ROC: 1,659 patients; Area under the curve (standard error) =0.82 (0.01); 95% CI 0.80, 0.84. Bold font indicates where the Youden index and kappa statistic are maximized.

Abbreviations: CI, confidence interval; ROC, receiver operating characteristic.

Figure 1 Graphical representation of the ROC curves analysis for CAT and mMRC.

Abbreviations: CAT, Chronic Obstructive Pulmonary Disease (COPD) Assessment Test; mMRC, modified Medical Research Council dyspnea scale; ROC, receiver operating characteristic.

Figure 2 mMRC and CAT sized groups as defined by GOLD-recommended cut point (1,653 patients).

Abbreviations: CAT, Chronic Obstructive Pulmonary Disease (COPD) Assessment Test; GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council dyspnea scale.

Figure 3 ROC and Cohen’s kappa-statistic sized segments as defined by ROC and kappa cut point (1,653 patients).

Abbreviations: CAT, Chronic Obstructive Pulmonary Disease (COPD) Assessment Test; GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council dyspnea scale; ROC, receiver operating characteristic.

Table 4 Regression analysis on movers

	Odds ratio	95% CI	P-value
GOLD-recommended cut points
Age <70 years	1.62	1.25–2.10	<0.001
Smoker	1.31	1.01–1.70	0.042
Cough in last 4 weeks	1.47	1.08–1.98	0.013
Condition having medium (3–5 on scale 0–10)a effect on daily activities in past week	1.79	1.34–2.40	<0.001
Condition having low restriction (1–3 on scale 1–5)b on living a normal life	2.76	1.86–4.09	<0.001
Not experiencing constant lack of energy	1.77	1.30–2.42	<0.001
Condition having no/low impact (1–2 on scale 1–7)c on getting up and ready for the day	2.84	1.75–4.60	<0.001
Condition having medium impact (3–4 on scale 1–7)c on getting up and ready for the day	1.85	1.17–2.93	0.009
Increased Jenkins sleep scale score (≥3 on a scale of 0–20)d	1.78	1.28–2.47	0.001
ROC-recommended cut points
Presence of cough in last 4 weeks	1.34	1.01–1.76	0.040
Condition having medium restriction (3 on a scale 1–5)b on living a normal life	4.15	2.79–6.17	<0.001
Condition having high restriction (4–5 on a scale 1–5)b on living a normal life	2.23	1.36–3.67	0.001
Condition having no/low/medium impact (1–4 on scale 1–7)c on getting up and ready for the day	1.96	1.27–3.04	0.003
Increased Jenkins sleep scale score (≥3 on a scale of 0–20)d	2.06	1.45–2.91	<0.001
Kappa statistic-recommended cut points
Age ≥55 years	1.56	1.08–2.24	0.017
Condition having medium/high restriction (3–5 on a scale 1–5)b on living a normal life	3.27	2.19–4.89	<0.001
Condition having medium impact (3–4 on scale 1–7)c on getting up and ready for the day	1.66	1.21–2.28	0.002
Condition having high impact (5–7 on scale 1–7)c on getting up and ready for the day	0.64	0.41–0.99	0.047
Increased Jenkins sleep scale score (≥3 on a scale of 0–20)d	1.72	1.20–2.47	0.003

Notes:

a Where 0= no effect and 10= prevented from undertaking daily activities;

b where 1= no restriction and 5= complete restriction on normal living;

c where 1= no impact and 7= constant impact on getting up and ready for the day;

d where 0= no impact on sleep and 20= high impact on sleep.

Abbreviations: CI, confidence interval; GOLD, Global Initiative for Chronic Obstructive Lung Disease; ROC, receiver operating characteristic.

Table 5 Regression analysis on moving left or righta

	Odds ratio	95% CI	P-value
ROC-recommended cut points
Not from France	2.45	1.20–5.02	0.014
Age <55 years	4.07	1.51–10.96	0.005
Presence of cough in last 4 weeks	2.11	1.29–3.43	0.003
Condition having little or no impact (1–2 on scale 1–7)b	1.82	1.05–3.16	0.032
On getting up and ready for the day
Increased Jenkins sleep scale score (≥7 on a scale 0–20)c	2.53	1.47–4.37	0.001
Kappa statistic-recommended cut points
Not from France	2.12	1.01–4.46	0.047
Age <55 years	3.78	1.62–8.80	0.002
Smoker	1.82	1.11–2.99	0.018
Presence of cough in last 4 weeks	2.38	1.41–4.02	0.001
Condition having little or no impact (1–2 on scale 1–7)b	2.18	1.24–3.84	0.007
On getting up and ready for the day
Increased Jenkins sleep scale score (≥7 on a scale 0–20)c	2.38	1.41–4.02	0.001

Notes:

a There were insufficient patients moving left to run this regression for GOLD-recommended cut points;

b where 1= no impact and 7= constant impact on getting up and ready for the day;

c where 0= no impact on sleep and 20= high impact on sleep.

Abbreviations: CI, confidence interval; GOLD, Global Initiative for Chronic Obstructive Lung Disease; ROC, receiver operating characteristic.

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