Health-related quality of life and long-term prognosis in chronic hypercapnic respiratory failure: a prospective survival analysis

Table 1 Baseline characteristics of patients according to the aetiology of CHRF.

Parameter	All patients	COPD	RD	NMD	OHS/OL
N	231	98	49	15	69
Gender (f/m)	86/145	28/70	28/21 **	5/10	25/44
Age (yrs)	62.9 ± 10.2	64.6 ± 8.2	63.2 ± 12.0	62.8 ± 7.1	60.3 ± 11.4 ***
BMI (kg/m²)	33.2 ± 9.9	29.4 ± 7.0	29.3 ± 5.6	28.9 ± 10.0	42.3 ± 9.9 ***
Ventilator use (h/d)	6.76 ± 2.52	6.70 ± 2.81	7.16 ± 2.11	7.20 ± 2.37	6.47 ± 2.39
Duration of HMV (months)	28.9 ± 8.8	29.6 ± 28.3	45.2 ± 36.9 *	27.4 ± 25.5	32.1 ± 25.2
Hb (g/dL)	13.7 ± 1.6	13.9 ± 1.7	13.7 ± 1.5	13.7 ± 1.2	13.5 ± 1.7
Leukocyte number (10³/μL)	8.97 ± 3.13	10.1 ± 3.5	7.5 ± 2.3 ***	7.2 ± 2.5*	8.8 ± 2.6 *
Heart disease, N (%)	65 (28.1)	29 (29.6)	11 (22.4)	5 (33.3)	20 (29.0)
Diabetes, N (%)	41 (17.7)	20 (20.4)	4 (8.1)	2 (13.3)	15 (21.7)
Hyperlipidaemia, N (%)	27 (11.7)	11 (11.2)	7 (14.2)	1 (6.7)	8 (11.6)
Hypertension, N (%)	121 (52.4)	42 (42.8)	22 (44.9)	7 (46.7)	50 (72.5) ***
FEV₁ (L)	1.25 ± 0.71	0.85 ± 0.26	0.89 ± 0.34	1.25 ± 0.58 *	2.08 ± 0.68 ***
FEV₁ (%pred)	48.7 ± 22.3	32.7 ± 8.7	44.0 ± 14.6 **	50.3 ± 24.0 **	73.9 ± 17.1 ***
FEV/IVC (%)	61.9 ± 17.8	45.8 ± 9.2	74.3 ± 9.9 ***	87.4 ± 17.2 ***	70.3 ± 11.4 ***
IVC (L)	2.05 ± 0.95	1.91 ± 0.55	1.19 ± 0.44 ***	1.44 ± 0.66 **	2.98 ± 0.94 ***
IVC (%pred)	70.0 ± 21.2	56.3 ± 13.9	48.4 ± 16.5 **	46.2 ± 22.6 *	82.8 ± 16.3 ***
pH	7.42 ± 0.04	7.42 ± 0.03	7.42 ± 0.04	7. 43 ± 0.03	7.43 ± 0.04
PaO₂ (mmHg)	68.0 ± 16.0	66.8 ± 16.2	71.1 ± 18.1	69.2 ± 19.1	67.2 ± 13.3
PaCO₂ (mmHg)	44.2 ± 6.8	46.4 ± 6.7	44.7 ± 6.6	40.5 ± 6.0**	41.6 ± 6.2 ***
BE (mmol/L)	3.93 ± 3.04	4.76 ± 3.33	3.84 ± 2.57	2.86 ± 2.06*	3.06 ± 2.81 **

Data are shown as mean ± SD. Characteristics of patients with COPD were compared with those of patients with other diseases using the unpaired t-test, Mann-Whitney U-test, or Fisher's exact test. P-values for individual tests were *p < 0.05; **p < 0.017 (corresponding to an overall p < 0.05 using a Bonferroni correction for three comparisons); ***p < 0.001. Definition of abbreviations: COPD = chronic obstructive pulmonary disease; RD = restrictive disease; NMD = neuromuscular disease; OHS = obesity-hypoventilation syndrome; OL = overlap syndrome: BMI = body-mass index; HMV = home mechanical ventilation; Hb = haemoglobin; FEV₁ = forced expiratory volume in one second; IVC = inspiratory vital capacity; PaO₂ = arterial oxygen tension; PaCO₂ = arterial carbon dioxide tension; BE = base excess. Blood gas parameters were obtained while patients were breathing room air (n = 147) or their usual oxygen flow (n = 84).

ISSN: 1465-993X