Prediction of exercise-induced desaturation in COPD patients without resting hypoxemia: a retrospective study

Yang, Lulu; Shi, Minghui; Situ, Xuanming; He, Jiaze; Qumu, Shiwei; Yang, Ting

doi:10.1186/s12890-022-02174-w

BMC Pulmonary Medicine

Table 2 Comparison of relevant indicators between different groups

From: Prediction of exercise-induced desaturation in COPD patients without resting hypoxemia: a retrospective study

Variables	new-EID patients (n = 13)	original-EID patients (n = 64)	P	EID patients (n = 77)	non-EID patients (n = 47)	P	P*
Male (n, %)	11 (84.62%)	56 (87.5%)	0.778	67 (87.01%)	34 (72.34%)	0.041
Age (y)	63.85 ± 9.08	64.44 ± 10.10	0.846	64.34 ± 9.88	63.21 ± 11.30	0.562	0.853
Height (m)	1.67 (1.58, 1.76)	1.64 (1.62, 1.72)	0.623	1.64 ± 20.57	1.66 ± 7.83	0.544	0.112
Weight (kg)	62.00 (57.00, 72.00)	64.25 (55.73, 72.30)	0.739	65.46 ± 13.18	64.06 ± 11.68	0.550	0.983
BMI (kg/m²)	21.51 (20.84, 24.45)	23.09 (20.58, 25.13)	0.545	23.14 ± 4.24	23.94 ± 3.53	0.280	0.291
GOLD stage (I: II: III: IV)	2:4:5:2	10:24:15:15	0.724	12:28:20:17	12:15:13:7	0.481	0.879
Baseline 6MWT
6MWD (m)	397.85 ± 112.56	415.78 ± 92.18	0.540	411.45 ± 94.54	464.85 ± 100.28	0.003	0.042
SpO_2rest (%)	96.00 (95.00, 97.00)	96.00 (95.00, 97.00)	0.699	96.00 (94.00, 97.00)	95.00 (94.00, 97.00)	0.329	0.576
SpO_2min (%)	91.00 (88.50, 93.50)	83.00 (80.00, 88.70)	< 0.001	87.00 (80.00, 90.00)	94.00 (94.00, 95.00)	< 0.001	< 0.001
SpO_2end (%)	94.00 (93.50, 96.00)	86.00 (84.00, 91.00)	< 0.001	88.00 (84.00, 92.00)	95.00 (94.00, 97.00)	< 0.001	0.027
SpO_2rest–SpO_2min (%)	4.00 (4.00, 8.00)	10.50 (7.00, 16.80)	< 0.001	9.00 (6.00, 15.00)	2.00 (0.00, 3.00)	< 0.001	< 0.001
SpO_2rest–SpO_2end (%)	2.00 (0.00, 3.00)	8.50 (6.00, 12.00)	< 0.001	6.00 (4.00, 11.00)	0.00 (-2.00, 2.00)	< 0.001	0.005
Lung function index
FVC (L)	3.07 ± 0.78	2.98 ± 0.83	0.751	3.00 ± 0.82	2.88 ± 0.91	0.454	0.505
FVC% pred (%)	94.69 ± 24.48	87.04 ± 22.83	0.295	88.24 ± 23.10	88.70 ± 21.46	0.915	0.406
FEV₁ (L)	1.47 (0.76, 2.60)	1.35 (0.84, 1.87)	0.786	1.43 ± 0.68	1.42 ± 0.59	0.953	0.650
FEV₁% pred (%)	61.72 (34.15, 96.00)	51.57 (29.76, 70.54)	0.663	53.05 ± 25.96	57.29 ± 22.89	0.202	0.963
D_LCO SB (mmol/min/kPa)	5.01 ± 1.85	4.63 ± 1.74	0.497	4.69 ± 1.76	5.72 ± 1.52	0.002	0.117
D_LCOSB% pred (%)	63.79 ± 22.09	56.37 ± 20.31	0.240	58.76 ± 22.29	72.66 ± 22.51	0.001	0.096
D_LCO/VA (mmol/min/kPa/L)	1.14 ± 0.32	1.00 ± 0.34	0.189	1.02 ± 0.34	1.31 ± 0.37	< 0.001	0.145
D_LCO/VA% pred (%)	84.88 ± 22.24	75.06 ± 22.98	0.162	75.10 ± 23.15	93.13 ± 23.17	< 0.001	0.176
Questionnaires
mMRC dyspnea scale	2 (1, 3)	2 (1, 3)	0.709	2 (1, 3)	2 (1, 2)	0.019	0.049
CAT score	19 (11, 26)	20 (15, 25)	0.978	20 (14.5, 25)	12 (7, 18)	< 0.001	0.009
BODE index	2 (1.5, 5)	3 (1, 5)	0.863	3 (1.5, 5)	2 (1, 4)	0.02	0.113
CT defined emphysema
mean density (HU)	− 848.20 (− 882.06, − 822.97)	− 843.44 (− 868.22, − 813.52)	0.251	− 860.10 ± 36.15	− 836.41 ± 40.18	0.028	0.157
PD15 (HU)	− 946.82 ± 32.69	− 961.40 ± 25.08	0.094	− 959.23 ± 26.61	− 946.43 ± 26.21	0.014	0.967
emphysema volume (ml)	159.84 (59.93, 1930.92)	579.56 (207.13, 1458.54)	0.245	578.50 (178.75, 1473.75)	196.66 (77.26, 694.12)	0.003	0.350
%LAA (%)	3.77 (1.36, 33.06)	12.61 (4.47, 21.79)	0.218	11.00 (4.00, 22.00)	4.16 (1.88, 12.01)	0.005	0.280
mean density of right lung (HU)	− 849.18 (− 877.59, − 822.87)	− 843.42 (− 872.72, − 822.36)	0.391	− 850.50 (− 875.50, − 824.50)	835.57 (− 855.24,− 807.53)	0.066	0.159
PD15 of right lung (HU)	− 946.09 ± 31.73	− 960.14 ± 25.09	0.472	− 958.05 ± 26.42	− 945.10 ± 27.96	0.014	0.919
emphysema volume of right lung (ml)	92.82 (37.81, 914.22)	345.80 (92.20, 702.27)	0.251	311.50 (86.75, 798.5)	98.9 (41.26, 425.47)	0.004	0.471
%LAA of right lung (%)	4.28 (1.54, 29.21)	12.87 (4.35, 20.61)	0.218	12.50 (4.00, 22.00)	3.49 (1.63, 12.47)	0.004	0.388
mean density of left lung (HU)	− 847.17 (− 887.17, − 822.11)	− 850.85 (− 869.02, − 919.80)	0.399	− 851.00 (− 875.50, − 822.00)	− 832.31 (− 858.65, − 797.52)	0.012	0.434
PD15 of left lung (HU)	− 940.00 (− 986.00, − 920.00)	− 964.50 (− 980.00, − 942.50)	0.210	− 958.09 ± 28.97	− 946.67 ± 28.19	0.414	0.937
emphysema volume of left lung (ml)	69.02 (22.11, 1016.70)	306.92 (117.48, 797.10)	0.335	285.00 (93.75, 831.50)	104.83 (22.75, 280.71)	0.003	0.251
%LAA of left lung (%)	3.23 (1.09, 37.41)	12.91 (4.26, 21.76)	0.216	12.00 (4.00, 22.00)	5.33 (1.14, 14.01)	0.007	0.406

EID Exercise-induced desatuation; BMI Body mass index; 6MWT 6 min-walk test; 6MWD 6 min-walk distance; SpO_2rest Resting blood oxygen saturation at the beginning of the test; SpO_2min Minimum blood oxygen saturation during the test; SpO_2end Blood oxygen saturation at the end of the test; FVC Forced vital capacity; FVC%pred Forced vital capacity as a percentage of predicted value; FEV₁ Forced expiratory volume in the first second; FEV₁%pred Forced expiratory volume in the first second as a percentage of predicted value; D_LCO SB Lung carbon monoxide diffusion; D_LCO SB%pred Lung carbon monoxide diffusion as a percentage of predicted value; D_LCO/VA Lung carbon monoxide diffusion per liter of alveolar air volume; D_LCO/VA%pred Lung carbon monoxide diffusion per liter of alveolar air volume as a percentage of predicted value; mMRC Modified Medical Research Council; CAT COPD Assessment Test; PD15 15th percentile point; %LAA % Low attenuation area
P * means the comparison between the new-EID and non-EID groups

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