Cognitive status among patients with chronic obstructive pulmonary disease

Figures & data

Table 1 Characteristics of all patients with and without cognitive impairment according to MMSE scores

Variable	Excluded patients	Included patients	MMSE <27	MMSE ≥27	P-value
Sex, males (n, %)	233 (73.1%)a	762 (81.6%)	299 (81.7%)	463 (81.5%)	>0.99
Age, years (mean, SD)	66.8 (9.4)	67.7 (10.0)	69.6 (9.5)	66.5 (10.1)	<0.001
Coexistence (n, %)
Alone	55 (17.1%)	121 (13.0%)	50 (13.6%)	71 (12.5%)	<0.001b
With partner	212 (66.0%)	646 (69.2%)	224 (61.0%)	422 (74.4%)
With family	47 (14.6%)	141 (15.1%)	75 (20.4%)	66 (11.6%)
Institutionalized	1 (0.3%)	12 (1.3%)	8 (2.2%)	4 (0.7%)
With professional caregiver	6 (1.9%)	14 (1.5%)	10 (2.7%)	4 (0.7%)
Educational level (n, %)
Basic literacy	47 (14.7%)a	74 (7.9%)	42 (11.4%)	32 (5.7%)	<0.001c
Primary level	190 (59.6%)	540 (57.9%)	251 (68.4%)	289 (51.1%)
Secondary level	62 (19.4%)	193 (20.7%)	52 (14.2%)	141 (25.0%)
Completed university	20 (6.3%)a	125 (13.4%)	22 (6.0%)	103 (18.2%)
COPD duration (mean, SD)	10.4 (6.4)	11.6 (7.7)	12.9 (8.0)	10.8 (7.4)	<0.001
Active smoker (n, %)	77 (25.8%)	206 (22.4%)	66 (18.4%)	140 (25.0%)	>0.99
Pack-years (mean, SD)	37.1 (20.4)	39.5 (21.8)	42.3 (24.8)	37.7 (19.4)	0.002
BMI (mean, SD)	27.5 (4.7)	27.8 (4.7)	27.9 (4.7)	27.7 (4.7)	0.52
Postbronchodilator spirometry (mean, SD)
FVC, mL	2,945 (977)	3,046 (977)	2,912 (922)	3,132 (1,001)	0.001
FVC, %	65.4 (21.2)a	71.0 (17.0)	71.3 (15.8)	70.8 (17.70)	0.55
FEV1, mL	1,805 (846)	1,886 (852)	1,778 (767)	1,957 (897)	0.002
FEV1, %	54.4 (21.0)	55.2 (17.8)	55.7 (17.9)	54.9 (17.7)	0.59
FEV1/FVC	56.6 (16.0)	58.5 (20.9)	57.2 (13.8)	59.4 (24.4)	0.13
Cough (n, %)	264 (85.7%)	770 (83.2%)	322 (89.7%)	448 (79.1%)	<0.001
Expectoration (n, %)	233 (78.4%)	669 (73.0%)	286 (79.7%)	383 (68.7%)	<0.001
Dyspnea, (n, %)	296 (94.0%)	891 (95.0%)	359 (97.5%)	532 (93.3%)	0.003
mMRC dyspnea score (mean, SD)	2.8 (0.9)	2.8 (0.9)	3.1 (0.9)	2.6 (0.9)	<0.001
Patient with exacerbations (n, %)	265 (79.6%)a	808 (86.0%)	351 (94.9%)	457 (80.2%)	<0.001
Number of hospital-treated exacerbations (emergency + admission) (mean, SD)	1.3 (0.5)a	1.4 (2.2)	1.8 (2.7)	1.0 (1.5)	<0.001
Oxygen therapy at home, (n, %)	65 (23.0%)	204 (23.4%)	130 (37.0%)	74 (14.2%)	<0.001
BODEx (mean, SD)	2.7 (1.8)	2.8 (1.9)	3.3 (1.8)	2.4 (1.9)	<0.001
Charlson comorbidity index (mean, SD)	1.3 (1.4)a	1.4 (1.4)	1.6 (1.5)	1.0 (0.6)	<0.001
BDI score (mean, SD)	9.3 (6.1)	9.0 (6.5)	11.7 (6.4)	7.2 (5.7)	<0.001
Suicidal ideation (n, %)	29 (9.4%)	123 (13.1%)	78 (21.2%)	45 (7.9%)	<0.001
Health status according to EQ-5D (mean, SD)	57.9 (17.1)	57.4 (19.2)	52.4 (18.2)	60.5 (19.2)	<0.001
Social tariff EQ-5D (mean, SD)	0.6 (0.2)	0.6 (0.2)	0.5 (0.2)	0.7 (0.2)	<0.001
CAT score (mean, SD)	21.6 (7.3)	21.6 (8.6)	25.2 (6.9)	19.3 (8.7)	<0.001
Physical activity grade (mean, SD)	4.1 (1.6)	4.3 (1.5)	3.7 (1.4)	4.6 (1.5)	<0.001
Minutes walked per day (mean, SD)	73.5 (68.2)a	64.2 (52.3)	56.1 (45.8)	68.8 (55.2)	0.001

Notes:

a Excluded vs included patients.

b Alone vs professional caregiver.

c Basic literacy vs completed university.

Abbreviations: BDI, Beck Depression Inventory; BMI, body mass index; BODEx, Body mass index, airflow Obstruction, Dyspnea and Exacerbations index; CAT, COPD Assessment Test; COPD, chronic obstructive pulmonary disease; EQ-5D, EuroQoL-5 dimensions; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; mMRC, Modified Medical Research Council scale; MMSE, mini-mental state examination; SD, standard deviation.

Table 2 Factors associated with cognitive impairment in univariate and multivariate analysis

Variable	Univariate			Multivariate
	OR	95% CI	P-value	OR	95% CI	P-value
Age (per 5-year increment)	1.177	1.099–1.262	<0.001
Educational level (completed university vs basic literacy)	0.160	0.080–0.310	<0.001	0.069	0.011–0.447	0.014
Postbronchodilator FVC	0.977	0.963–0.991	0.001
Postbronchodilator FEV1	0.975	0.959–0.991	0.003
Cough	2.290	1.540–3.410	<0.001
Expectoration	1.780	1.300–2.430	<0.001
Presence of dyspnea (yes vs no)	2.850	1.360–5.960	0.005
Exacerbations in the previous year (yes vs no)	4.570	2.750–7.570	<0.001
Oxygen therapy	3.180	1.070–9.440	0.037
BODEx	1.280	1.179–1.389	<0.001
Charlson comorbidity index	1.590	1.435–1.762	<0.001
BDI score	1.125	1.098–1.152	<0.001
Suicide ideation	3.150	2.120–4.670	<0.001
Health status according to EQ-5D	0.799	0.742–0.860	<0.001
Social tariff EQ-5D	0.971	0.965–0.977	<0.001	0.967	0.950–0.983	<0.001
CAT score	1.098	1.078–1.118	<0.001
Physical activity grade	0.648	0.587–0.715	<0.001
Minutes walked per day	0.994	0.991–0.998	0.001

Abbreviations: BDI, Beck Depression Inventory; BODEx, Body mass index, airflow Obstruction, Dyspnea and Exacerbations index; CAT, COPD Assessment Test; CI, confidence interval; EQ-5D, EuroQoL-5 dimensions; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; OR, odds ratio.

Table 3 Factors associated with cognitive impairment in univariate and multivariate analysis, including only demographic and clinical variables

Variable	Univariate			Multivariate
	OR	95% CI	P-value	OR	95% CI	P-value
Age (per 5-year increment)	1.177	1.099–1.262	<0.001
Educational level (completed university vs basic literacy)	0.160	0.080–0.310	<0.001	0.063	0.010–0.394	0.010
Postbronchodilator FVC	0.977	0.963–0.991	0.001
Postbronchodilator FEV1	0.975	0.959–0.991	0.003
Cough	2.290	1.540–3.410	<0.001
Expectoration	1.780	1.300–2.430	<0.001
Dyspnea	2.850	1.360–5.960	0.005
Exacerbations	4.570	2.750–7.570	<0.001	11.070	1.450–84.534	0.020
Oxygen therapy	3.180	1.070–9.440	0.037
BODEx	1.280	1.179–1.389	<0.001	1.261	1.049–1.515	0.014
Charlson comorbidity index	1.590	1.435–1.762	<0.001	1.412	1.118–1.783	0.004
Suicide ideation	3.150	2.120–4.670	<0.001
Physical activity grade	0.648	0.587–0.715	<0.001
Minutes walked per day	0.994	0.991–0.998	0.001

Abbreviations: BODEx, Body mass index, airflow Obstruction, Dyspnea and Exacerbations index; CI, confidence interval; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; OR, odds ratio.

Figure 1 Flow diagram for the analysis.

Abbreviation: MMSE, mini-mental state examination.