Exploring the Association Between Emphysema Phenotypes and Low Bone Mineral Density in Smokers with and without COPD

Figures & data

Figure 1 Flowchart showing the inclusion of the participant.

Table 1 Baseline Clinical, Radiographic and Densitometric Characteristics of Patients with and without Low Bone Mineral Density (Osteopenia and Osteoporosis)

Characteristics	Normal Bone Density (n=38)	Low Bone Mineral Density (n=115)	p value
Demographic
Age years-old, Mean (SD)	61.4 (9.3)	63.5 (7.6)	0.175
Male, No (%)	28 (73.7)	56 (49.1)	0.008
BMI Kg/m^2, Mean (SD)	29.7 (4.3)	26.4 (4.5)	<0.001
Clinical
Active smoker, No (%)	15 (39.4)	59 (51.3)	0.206
Pack-years of smoking, Median (IQR)	43.9 (28.5)	47.6 (28.9)	0.491
COPD, No (%)	22 (59.5)	82 (71.9)	0.155
Inhaled steroids, No (%)	7 (19.4)	32 (28.1)	0.304
Radiographic
Emphysema, No (%)	10 (26.3)	76 (66.1)	<0.001
Type of emphysema, No (%)			<0.001
Centrilobular alone	3 (7.9)	36 (31.3)
Centrilobular and paraseptal	5 (13.2)	35 (30.4)
Paraseptal alone	2 (5.3)	5 (4.3)
Severity of emphysema, by NETT (0–4), Median (IQR)	0.5 (1)	1.1 (1)	0.004
Pulmonary function tests
FVC-L, Mean (SD)	4.1 (0.9)	3.5 (1.2)	0.052
FVC-%, Mean (SD)	114.5 (20.6)	114.9 (24.6)	0.952
FEV1-L, Mean (SD)	2.5 (0.7)	2 (0.8)	0.007
FEV1-%, Mean (SD)	88.8 (19.2)	81.1 (25.6)	0.161
FEV1/FVC, Median (IQR)	62.6 (12.4)	56.9 (14)	0.077
DLCO-mL/min/mmHg, Mean (SD)	20.7 (5.7)	18.8 (6.2)	0.008
DLCO-%, Mean (SD)	80.3 (18.9)	69.2 (21.1)	0.026
6MWT-meters, Median (IQR)	534.2 (103.5)	479 (109.2)	0.031

Abbreviations: SD, standard deviation; BMI, body mass index; IQR, interquartil range (25–75 percentile); NETT, national emphysema treatment trial; COPD, Chronic Obstructive Pulmonary Disease; GOLD, Global Initiative for Chronic Obstructive Lung Disease; BODE, Body-mass index, airflow Obstruction, Dyspnea, and Exercise; FVC, forced vital capacity; FEV1, forced expiratory volume-one second; DLCO, diffusing capacity for carbon monoxide; 6WMT, six minutes walking test.

Table 2 Predictors of Low Bone Mineral Density (Osteopenia/Osteoporosis) in Current and Former Smokers, Univariate Analysis

Variables	OR	IC 95%	P value
Age years-old	1.03	0.98–1.08	0.176
Male	0.34	0.15–0.77	0.010
BMI Kg/m^2	0.84	0.76–0.92	<0.001
Active smoker	1.61	0.76–3.40	0.208
Pack-years	1	0.99–1.01	0.490
Inhaled steroids	1.61	0.64–4.06	0.307
COPD	1.74	0.80–3.78	0.157
BODE	1.51	0.92–2.47	0.099
Post-bronchodilator FEV1 (L)	0.43	0.24–0.80	0.008
DLCO (mL/min/mmHg)	0.90	0.83–0.97	0.012
6MWT meters	0.99	0.98–0.99	0.034
Emphysema	5.45	2.40–12.37	<0.001
Severity of emphysema, by NETT (0–4)	1.83	1.19–2.81	0.006
Type of emphysema
Centrilobular alone	8.61	2.40–30.79	0.001
Centrilobular and paraseptal	5.02	1.74–14.43	0.003
Paraseptal alone	1.79	0.32–9.92	0.503

Abbreviations: COPD, Chronic Obstructive Pulmonary Disease; BMI, body mass index; NETT, national emphysema treatment trial; FEV1, forced expiratory volume-one second; DLCO, diffusing capacity for carbon monoxide; 6WMT, six minutes walking test.

Table 3 Predictors of Low Bone Mineral Density (Osteopenia/Osteoporosis) in Current and Former Smokers, Multivariate Analysis

Variables	OR	IC 95%	P value
Age years-old	1.02	0.94–1.10	0.577
Male	0.39	0.09–1.61	0.194
BMI Kg/m^2	0.91	0.76–0.92	<0.001
Post-bronchodilator FEV1 (L)	0.54	0.23–1.27	0.161
Severity of emphysema, by NETT (0–4)	0.46	0.17–1.19	0.112
Type of emphysema
Centrilobular alone	26.19	1.71–399.44	0.019
Centrilobular and paraseptal	23.53	2.03–272.62	0.011
Paraseptal alone	4.23	0.31–57.68	0.278

Abbreviations: BMI, body mass index; NETT, national emphysema treatment trial; FEV1, forced expiratory volume-one second.