Anemia and performance status as prognostic markers in acute hypercapnic respiratory failure due to chronic obstructive pulmonary disease

Figures & data

Table 1 The Early Warning Score (EWS)

Score	0	1	2	3
Heart rate	51–100	40–50	<40	>130
(beats per minute)		101–110	111–130
Systolic blood	101–160	81–100	70–80	<70
pressure (mmHg)		161–200	>200
Respiratory rate	9–14	15–20	<9	>30
(per minute)			21–30
Temperature	36.1–37.5	35.0–36.0	<35
(degrees celsius)		>37.5
Consciousness level	Alert	Responds to voice	Responds to pain	Unresponsive

Table 2 Inpatient demographics, COPD severity, comorbidities, and performance status¶

	Survived inpatient stay (n = 43)	Died as an inpatient (n = 22)
Total	66.2% (43/65)	33.8% (22/65)	P > 0.05
Male	58.6% (17/29)	41.4% (12/29)
Female	72.2% (26/36)	27.8% (10/36)
Age, years*	69.6 (9.5)	74.1 (1.49)	P > 0.05
FEV1, L/s	0.78 (0.38)	0.51 (0.26)	P < 0.05
FEV1, % predicted	34.8 (13.3)	26.5 (16.2)	P < 0.05
GOLD stage
2	13.9%	5.3%
3	18.6%	15.7%
4	67.4%	78.9%	P > 0.05
Admissions/year	1.30 (2.03)	1.45 (1.47)	P > 0.05
Previous AHRF	55.8%	59%	P > 0.05
LTOT	32.6%	59%	P < 0.05
Age adjusted CCI	4.0 (1.49)	4.3 (1.32)	P = 0.47
Body mass index
<18.5 Kg/m^2	26.8%	33.3%	P > 0.05
18.5–30 Kg/m^2	53.6%	47.6%	P > 0.05
>30 Kg/m^2	19.5%	19%	P > 0.05
Performance status	2 (0–4)	3 (1–4)	P < 0.001
(WHO-PS)
WHO-PS ≥ 3	21%	91%	P < 0.0001

Note: *Expressed as mean (SD) and ^¶expressed as median (range).

Abbreviations: AHRF, acute hypercapnic respiratory failure; CCI, Charlson comorbidity index (Charlson et al, 1987);¹⁴ COPD, chronic obstructive pulmonary disease; FEV₁, forced expiratory volume in 1 second; GOLD, global initiative for chronic obstructive lung disease; LTOT, long-term oxygen therapy; SD, standard deviation; WHO-PS, World Health Organization performance status.

Table 3 Physiological measurements on admission

	Survived inpatient stay (n = 43)	Died as an inpatient (n = 22)
Heart Rate/minute	100.0 (21.7)	110.0 (19.1)	P = 0.072
Respiratory Rate/minute	25.9 (7.2)	31.2 (8.9)	P < 0.05
BP systolic (mmHg)	140.4 (25.8)	127 (26.6)	P = 0.06
BP diastolic (mmHg)	75.4 (13.3)	66.6 (15.2)	P < 0.01
GCS	14.4 (1.3)	13.1 (2.8)	P < 0.05
EWS	3.5 (1.8)	4.7 (1.5)	P < 0.05

Abbreviations: BP, blood pressure; GCS, Glasgow Coma Scale; EWS, Early Warning Score.

Table 4 Laboratory variables on admission

	Survived inpatient stay (n = 43)	Died as an inpatient (n = 22)
pH prior to commencing noninvasive ventilation	7.24 (0.07)	7.19 (0.08)	P > 0.05
pH < 7.26	48.8%	59%	P > 0.05
pH < 7.20	16.3%	45.5%	P = 0.014
A–a gradient, mmHg	78.8 (168)	46.3 (138)	P > 0.05
pCO2, mmHg	82.9 (23.6)	98.5 (32.6)	P = 0.030
Hb, g/dL	13.3 (2.0)	11.5 (1.67)	P < 0.005
Anemia	27.9%	68.2%	P = 0.002
Albumin g/dL	37.1 (4.2)	34.8 (4.1)	P < 0.05
Hypoalbuminemia	22%	47.6%	P < 0.05
Urea, mmol/L	8.9 (5.1)	11.5 (8.8)	P > 0.05
Urea > 7 mmol/L	55.8%	54.5%	P > 0.05
CRP, mg/L	94.5 (120.2)	163.8 (150.1)	P < 0.05

Notes: Anemia was defined as Hb < 13.0 g/dL in males and Hb < 11.5 g/dL in females. Hypoalbuminemia was defined as albumin < 35 g/L.

Abbreviations: A–a, alveolar-arterial; CRP, C-reactive protein; Hb, hemoglobin; pCO₂, partial pressure of CO₂.

Table 5 Univariate analysis of variables associated with inpatient death

	OR	95% confidence interval		Significance
		Lower	Upper
WHO-PS ≥ 3	37.7	7.41	192.50	P < 0.0001
Long-term oxygen therapy	2.99	1.03	8.60	P < 0.043
Anemia	5.54	1.81	16.92	P = 0.003
Diastolic BP < 70 mmHg	4.20	1.41	12.51	P = 0.010
EWS ≥ 3	11.25	1.37	92.02	P < 0.024
pH < 7.20	3.65	1.17	11.37	P < 0.017
Albumin < 35 g/L	3.23	1.04	10.02	P = 0.042

Abbreviations: BP, blood pressure; EWS, Early Warning Score; OR, odds ratio; WHO-PS, World Health Organization performance status.

Figure 1 Kaplan–Meier curve of patient survival up to 1 year following hospital admission. The red crosses represent censored data.

Abbreviation: WHO-PS, World Health Organization performance status.

CharlsonMEPompeiPAlesKLMacKenzieCRA new method of classifying prognostic comorbidity in longitudinal studies: development and validationJ Chronic Dis19874053733833558716

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