Interaction of Acute Respiratory Failure and Acute Kidney Injury on in-Hospital Mortality of Patients with Acute Exacerbation COPD

Figures & data

Table 1 Characteristics of Participants Categorized by ARF and AKI

Variables	Neither ARF nor AKI (n = 932)	ARF Only (n = 358)	AKI Only (n = 200)	Both ARF and AKI (n = 157)	P value
Demographics
Gender (male), n (%)	722 (77.5)	265 (74.0)	157 (78.5)	117 (74.5)	0.476
Age (years)	77 (70–83)	78 (69–83)	82 (76–85)	80 (76–86)	<0.001
Comorbid conditions, n (%)
Hypertension	480 (51.5)	176 (49.2)	126 (63.0)	90 (57.3)	0.007
Anemia	237 (25.4)	115 (32.1)	85 (42.5)	67 (42.7)	<0.001
Diabetes mellitus	138 (14.8)	60 (16.8)	38 (19.0)	28 (17.8)	0.412
Coronary artery disease	244 (26.2)	78 (21.8)	85 (42.5)	65 (41.4)	<0.001
Chronic cor pulmonale	288 (30.9)	214 (59.8)	85 (42.5)	84 (53.5)	<0.001
Atrial fibrillation	92 (9.9)	25 (7.0)	35 (17.5)	22 (14.0)	0.001
Cerebrovascular diseases	187 (20.1)	63 (17.6)	84 (27.0)	40 (25.5)	0.026
Laboratory tests
Albumin (g/L)	35.7 (33.1–38.3)	34.4 (32.1–37.2)	34.9 (32.1–37.7)	32.5 (29.0–35.4)	<0.001
Neutrophil ratio (%)	74.8 (66.6–82.8)	81.2 (72.8–88.2)	80.1 (73.0–88.4)	86.8 (80.1–91.0)	<0.001
Platelet count (10^9/L)	188 (147–228)	177 (135–222)	181 (146–216)	155 (121–203)	<0.001
Triglyceride (mmol/L)	0.80 (0.62–1.11)	0.82 (0.66–1.07)	0.88 (0.67–1.18)	0.91 (0.70–1.16)	0.125
Total cholesterol (mmol/L)	3.96 (3.35–4.65)	3.94 (3.39–4.65)	3.94 (3.30–4.77)	3.54 (2.97–4.49)	0.005
High density lipoprotein (mmol/L)	1.18 (0.97–1.39)	1.16 (0.94–1.40)	1.11 (0.90–1.36)	1.03 (0.80–1.25)	<0.001
Low density lipoprotein (mmol/L)	2.35 (1.82–2.94)	2.34 (1.92–2.95)	2.42 (1.84–2.96)	2.05 (1.49–2.77)	0.124
Outcome
In-hospital mortality, n (%)	7 (0.8)	25 (7.0)	15 (7.5)	47 (29.9)	<0.001

Abbreviations: ARF, acute respiratory failure; AKI, acute kidney injury.

Table 2 Univariate Logistic Analysis of Risk Factors for in-Hospital Death in Patients with AECOPD

Variables	All Patients (n=1647)	Survival Group (n=1553)	Death Group (n=94)	P value
Demographics
Gender (male)	1261 (76.6)	1192 (76.8)	69 (73.4)	0.456
Age (years)	78 (71–84)	78 (70–83)	81 (78–86)	<0.001
Comorbid conditions, n (%)
Hypertension	872 (52.9)	824 (53.1)	48 (51.1)	0.707
Anemia	504 (30.6)	463 (29.8)	41 (43.6)	0.005
Diabetes mellitus	264 (16.0)	246 (15.8)	18 (19.1)	0.396
Coronary artery disease	472 (28.7)	433 (27.9)	39 (41.5)	0.005
Chronic cor pulmonale	671 (40.7)	620 (39.9)	51 (54.3)	0.006
Atrial fibrillation	174 (10.6)	160 (10.3)	14 (14.9)	0.160
Cerebrovascular diseases	344 (20.9)	321 (20.7)	23 (24.5)	0.379
Laboratory tests
Albumin (g/L)	35.0 (32.4–37.8)	35.2 (32.6–37.9)	31.7 (27.8–35.1)	<0.001
Neutrophil ratio (%)	78.4 (69.6–86.0)	77.9 (69.0–85.5)	86.0 (79.6–90.8)	<0.001
Platelet count (10^9/L)	182 (141–224)	184 (142–225)	161 (124–209)	0.007
Triglyceride (mmol/L)	0.82 (0.64–1.12)	0.82 (0.64–1.11)	0.95 (0.68–1.21)	0.030
Total cholesterol (mmol/L)	3.93 (3.31–4.63)	3.94 (3.32–4.63)	3.75 (3.08–4.59)	0.110
High density lipoprotein (mmol/L)	1.15 (0.94–1.38)	1.16 (0.94–1.38)	1.06 (0.83–1.32)	0.014
Low density lipoprotein (mmol/L)	2.32 (1.81–2.93)	2.35 (1.82–2.93)	2.10 (1.64–2.65)	0.012
Complications of ARF and AKI, n (%)
Neither ARF nor AKI	932 (56.6)	925 (59.6)	7 (7.4)
ARF only	358 (21.7)	333 (21.4)	25 (26.6)	<0.001
AKI only	200 (12.1)	185 (11.9)	15 (16.0)	<0.001
Both ARF and AKI	157 (9.5)	110 (7.1)	47 (50.0)	<0.001

Abbreviations: ARF, acute respiratory failure; AKI, acute kidney injury; AECOPD, acute exacerbation of chronic obstructive pulmonary disease.

Table 3 Multivariate Logistic Analysis of Risk Factors for in-Hospital Death in Patients with AECOPD

Variables	Mortality (%)	OR	95% CI	P value
Albumin	–	0.88	0.83–0.93	<0.001
Complications of ARF and AKI
Neither ARF nor AKI	0.8% (7/932)	Reference	Reference
ARF only	7.0% (25/358)	8.53	3.64–19.99	<0.001
AKI only	7.5% (15/200)	8.99	3.58–22.55	<0.001
Both ARF and AKI	29.9% (47/157)	39.13	17.02–89.97	<0.001

Abbreviations: ARF, acute respiratory failure; AKI, acute kidney injury; AECOPD, acute exacerbation of chronic obstructive pulmonary disease; OR, odds ratio; CI, confidence interval.

Table 4 Measures for Estimation of Biological Interaction Between ARF and AKI for the Risk of in-Hospital Death in Patients with AECOPD

Measures of Biological Interaction	Estimate	95% CI
RERI	22.62	0.31–44.93
AP	0.59	0.36–0.79
SI	2.46	1.44–4.20

Abbreviations: ARF, acute respiratory failure; AKI, acute kidney injury; AECOPD, acute exacerbation of chronic obstructive pulmonary disease; RERI, relative excess risk due to interaction; AP, attributable proportion; SI, synergy index; CI, confidence interval.

Figure 1 Relative risk with contributions from ARF, AKI, or a combination of both.

Abbreviations: ARF, acute respiratory failure; AKI, acute kidney injury.