Severe hypoalbuminemia is a strong independent risk factor for acute respiratory failure in COPD: a nationwide cohort study

Figures & data

Figure 1 Flow chart of patient enrollment.

Table 1 Demographic and clinical characteristics of COPD patients with and without hypoalbuminemia

Characteristics	No hypoalbuminemia (n=40,871)	Hypoalbuminemia (n=1,861)	P-value
Duration of follow-up, months
Mean ± SD	73.96±44.08	67.21±48.27	<0.001
Sex
Female	17,660 (43.21)	601 (32.29)	<0.001
Male	23,211 (56.79)	1,260 (67.71)
Age (years)
40–54	10,268 (25.12)	120 (6.45)	<0.001
55–64	8,463 (20.71)	191 (10.26)
65–74	10,751 (26.30)	544 (29.23)
75+	11,389 (27.87)	1,006 (54.06)
Mean ± SD	65.69±13.23	74.66±10.78	<0.001
Occupation*
I	15,368 (37.60)	546 (29.34)	<0.001
II	7,071 (17.30)	199 (10.69)
III	10,396 (25.44)	598 (32.13)
IV–VI	8,036 (19.66)	518 (27.83)
Urbanization of living area
I (highest)	10,865 (26.71)	432 (23.29)	<0.001
II	11,295 (27.77)	439 (23.67)
III	6,728 (16.54)	336 (18.11)
IV (lowest)	11,785 (28.97)	648 (34.93)
ESRD
Without	40,508 (99.11)	1,831 (98.39)	<0.001
With	363 (0.89)	30 (1.61)
DM
Without	27,817 (68.06)	1,083 (58.19)	<0.001
With	13,054 (31.94)	778 (41.81)
Hypertension
Without	13,711 (33.55)	436 (23.43)	<0.001
With	27,160 (66.45)	1,425 (76.57)
IHD
Without	24,146 (59.08)	822 (44.17)	<0.001
With	16,725 (40.92)	1,039 (55.83)
Stroke
Without	34,898 (85.39)	1,261 (67.76)	<0.001
With	5,973 (14.61)	600 (32.24)
Parkinson disease
Without	38,429 (94.03)	1,653 (88.82)	<0.001
With	2,442 (5.97)	208 (11.18)
Malignancy
Without	37,802 (92.49)	1,577 (84.74)	<0.001
With	3,069 (7.51)	284 (15.26)
Steroid
Without	36,764 (89.95)	1,623 (87.21)	<0.001
With	4,107 (10.05)	238 (12.79)
Blood transfusion
Without	34,204 (83.69)	300 (16.12)	<0.001
With	6,667 (16.31)	1,561 (83.88)
ARF
Without	36,578 (97.58)	4,293 (81.80)	<0.001
With	906 (2.42)	955 (18.20)

Notes: Data values are presented as number (%) unless otherwise stated.

* The occupations of patients were presented as four types according to the classification of beneficiaries in NHI; type I included civil servants, most employees, employers, and independently practicing professionals or technicians; type II included workers without particular employers or those who were self-employed, seamen or master mariners serving on foreign vessels; type III were mostly farmers and fishermen; type IV–VI mainly included members of low-income families, veterans and their families, and others.

Abbreviations: ARF, acute respiratory failure; ESRD, end-stage renal disease; DM, diabetes mellitus; IHD, ischemic heart disease; NHI, Taiwan’s National Health Insurance; SD, standard deviation.

Table 2 Demographic and clinical characteristics of COPD patients with (n=5,248) and without (n=37,484) developing ARF

Characteristics	ARF		Crude HR (95% CI)	P-value
	Without, %	With, %
Hypoalbuminemia
Without	89.5	10.5	Ref
With	48.68	51.32	5.35 (4.98–5.74)	<0.001
Steroid
Without	89.09	10.91	Ref
With	75.6	24.4	2.25 (2.10–2.41)	<0.001
Blood transfusion
Without	91.09	8.91	Ref
With	73.6	26.4	2.70 (2.50–2.86)	<0.001
Sex
Female	90.46	9.54	Ref
Male	85.67	14.33	1.55 (1.46–1.64)	<0.001
Age (years)
40–54	97.66	2.34	Ref
55–64	94.25	5.75	2.59 (2.22–3.02)	<0.001
65–74	85.68	14.32	6.18 (5.40–7.08)	<0.001
75+	76.68	23.32	11.33 (9.93–12.92)	<0.001
Occupation*
I	90.86	9.14	Ref
II	93.04	6.96	0.77 (0.69–0.85)	<0.001
III	83.9	16.1	1.73 (1.62–1.86)	<0.001
IV–VI	82.25	17.75	1.88 (1.75–2.02)	<0.001
Urbanization of living area
I (highest)	90.33	9.67	Ref
II	89.08	10.92	1.12 (1.03–1.21)	0.007
III	86.93	13.07	1.37 (1.26–1.50)	<0.001
IV (lowest)	84.43	15.57	1.60 (1.49–1.73)	<0.001
ESRD
Without	87.81	12.19	Ref
With	77.86	22.14	1.67 (1.35–2.07)	<0.001
DM
Without	89.3	10.7	Ref
With	84.42	15.58	1.36 (1.29–1.44)	<0.001
Hypertension
Without	91.59	8.41	Ref
With	85.8	14.2	1.52 (1.42–1.62)	<0.001
IHD
Without	90.21	9.79	Ref
With	84.22	15.78	1.39 (1.32–1.47)	<0.001
Stroke
Without	90.87	9.13	Ref
With	70.41	29.59	3.16 (2.99–3.34)	<0.001
Parkinson disease
Without	88.49	11.51	Ref
With	76.04	23.96	2.00 (1.84–2.17)	<0.001
Malignancy
Without	87.84	12.16	Ref
With	86.28	13.72	0.99 (0.90–1.09)	0.818

Notes:

* The occupations of patients were presented as four types according to the classification of beneficiaries in NHI; type I included civil servants, most employees, employers, and independently practicing pro fessionals or technicians; type II included workers without particular employers or those who were self-employed, sea men or master mariners serving on foreign vessels; type III were mostly farmers and fishermen; type IV–VI major included members of low-income families, veterans and their families, and others.

Abbreviations: ARF, acute respiratory failure; HR, hazard ratio; CI, confidence interval; Ref, reference group; ESRD, end-stage renal disease; DM, diabetes mellitus; IHD, ischemic heart disease; NHI, Taiwan’s National Health Insurance.

Table 3 Adjusted hazard ratio of ARF related to patient’s characteristics

Parameters	AHR	95% CI	P-value
Hypoalbuminemia
With vs without	2.87	2.65–3.10	<0.001
Use of steroid
Ever vs never	1.97	1.84–2.11	<0.001
Blood transfusion
Ever vs never	0.74	0.70–0.79	<0.001
Age (years)
40–54	Ref
55–64	2.36	2.02–2.75	<0.001
65–74	4.63	4.02–5.34	<0.001
75+	7.48	6.51–8.60	<0.001
Sex
Male vs female	1.32	1.24–1.40	<0.001
Occupation*
I	Ref
II	1.01	0.91–1.12	0.866
III	0.95	0.87–1.03	0.222
IV–VI	1.08	1.00–1.16	0.060
Urbanization of living area
I (highest)	Ref
II	1.06	0.97–1.15	0.188
III	1.17	1.07–1.28	0.001
IV (lowest)	1.25	1.15–1.37	<0.001
ESRD
With vs without	1.27	1.02–1.57	0.031
DM
With vs without	1.12	1.06–1.18	0.000
Hypertension
With vs without	0.83	0.77–0.89	<0.001
IHD
With vs without	0.93	0.88–0.99	0.019
Parkinson’s disease
With vs without	1.11	1.02–1.20	0.021
Stroke
With vs without	1.90	1.79–2.02	<0.001
Malignancy
With vs without	0.72	0.65–0.79	<0.001

Notes:

* The occupations of patients were presented as four types according to the classification of beneficiaries in NHI; type I included civil servants, most employees, employers, and independently practicing pro fessionals or technicians; type II included workers without particular employers or those who were self-employed, sea men or master mariners serving on foreign vessels; type III were mostly farmers and fishermen; type IV–VI major included members of low-income families, veterans and their families, and others.

Abbreviations: ARF, acute respiratory failure; AHR, adjusted hazard ratio; CI, confidence interval; Ref, reference group; ESRD, end-stage renal disease; DM, diabetes mellitus; IHD, ischemic heart disease; NHI, Taiwan’s National Health Insurance.

Figure 2 Adjusted hazard ratios of risk of acute respiratory failure associated with annual average dose of albumin supplementation.

Note: Severe hypoalbuminemia is defined as average dose of albumin supplementation >13.8 g per year.
Abbreviations: HR, hazard ratio; yr, year.