ST2 Predicts Mortality In Patients With Acute Hypercapnic Respiratory Failure Treated With Noninvasive Positive Pressure Ventilation

Figures & data

Table 1 Characteristics Of The Patients, As A Whole Group And Divided Into Subgroups

	Whole Group	AECOPD	AHF	AEOHS	P value^b
General characteristics
Number of patients	46	34	8	4
Age years: median (IQR)	77.1 (68.7–84.0)	76.9 (68.8–83.9)	82.3 (77.7–86.8)	65.4 (60.5–73.0)	0.035
BMI kg/m^2: median (IQR)	23.4 (20.5–36.1)	24.0 (18.8–28.2)	27.7 (21.7–39.2)	46.6 (39.3–55.2)	0.004
Gender female %	65% (30/46)	65% (22/34)	63% (5/8)	75% (3/4)	0.054
Active or ex-smokers %	87% (40/46)	97% (33/34)	63% (5/8)	50% (2/4)	<0.001
FEV1%: median (IQR)	31 (24–43)	29 (22–36)	47^a	43^a	0.058
Variables related to AHRF
pH: median (IQR)	7.28 (7.24–7.36)	7.31 (7.24–7.37)	7.24 (7.10–7.31)	7.30 (7.25–7.35)	0.17
pO2 kPa: median (IQR)	7.45 (6.33–8.73)	6.85 (6.10–8.48)	7.50 (5.60–9.58)	8.40 (8.23–10.68)	0.24
pCO2 kPa: median (IQR)	8.75 (7.78–10.5)	8.90 (7.78–10.35)	8.05 (6.38–10.73)	10.05 (8.45–11.73)	0.30
Base excess mEq/L: median (IQR)	5.1 (1–10)	6.4 (4–10)	− 3 (−7.5–0)	11.3^a	<0.001
Respiratory rate bpm: median (IQR)	26 (20–29)	26 (20–29)	24 (22–29)	25 (21–27)	0.89
CRP mg/L: median (IQR)	15.5 (8.3–76.5)	36.5 (9.7–93.0)	8.7 (6.4–11.0)	12.5 (7.5–37.0)	0.076
Laktat mmol/L: median (IQR)	1.40 (0.80–2.75)	1.10 (0.80–2.10)	3.80 (2.78–5.63)	1.20 (0.80–2.35)	0.09
NPPV use first 4 hrs: median (IQR)	3.57 (3.50–4.00)	3.67 (3.50–4.00)	3.50 (2.50–4.00)	3.75 (3.50–4.00)	0.67

Notes: ^aVariable number too small to analyse IQR. ^bWe used Kruskal–Wallis test for all but gender and smoking status, there we used Fisher´s exact test.

Abbreviations: IQR, interquartile range; AECOPD, acute exacerbation of COPD; AHF, acute heart failure; AEOHS, acute exacerbation of obesity hypoventilation syndrome; BMI, body mass index, FEV1, forced expiratory volume in 1 second; CRP, C-reactive protein; NPPV, noninvasive positive pressure ventilation.

Figure 1 Correlation between ST2 values measured with Olink biomarker panel and Presage ST2 clinical assay.

Table 2 Relationship Between ST2 And Risk Of 28 Days And 18 Months Mortality

ST2 On Admission vs 28 Days Follow-Up Mortality (Model 1 And 2)
Continuous ST2 Analysis (Per SD Increment)		P-value	Tertile 1	Tertile 2	Tertile 3	p For Trend
N/N events^a	46/13		15/0	16/2	15/11
HR (95% CI) (age and gender adjusted)	11.00 (1.8–67.2)	0.009	n/a^c	n/a^c	n/a^c	0.002
HR (95% CI) (age, gender and CRP adjusted)^b	12.55 (2.0–77.2)	0.006	n/a^c	n/a^c	n/a^c	0.001
ST2 On Admission vs 18 Months Follow-Up Mortality (Model 1 And 2)
Continuous ST2 Analysis (Per SD Increment)		P-value	Tertile 1	Tertile 2	Tertile 3	p For Trend
N/N events^a	46/30		15/7	15/10	16/13
HR (95% CI) (age and gender adjusted)	2.11 (1.4–3.2)	0.001	1.0 (ref)	1.54 (0.6–4.2)	5.50 (2.1 14.4)	0.001
HR (95% CI) (age, gender and CRP adjusted)^b	2.47 (1.6–3.9)	<0.001	1.0 (ref)	1.74 (0.7–4.6)	5.71 (2.2–4.7)	<0.001

Notes: ^aMortality within the follow-up period. ^bBackward elimination model. ^cAnalysis not possible due to zero number of events in the Tertile 1 group.

Abbreviations: SD, standard deviation; HR, hazard ratio; CI, confidence interval; CRP, C-reactive protein.

Figure 2 Kaplan–Meier plot showing cumulative mortality during 18 months follow-up period. Tertile 1 denotes the lowest values of ST2, and Tertile 3 the highest values.

Table 3 ST2, pCO₂ And pH Values Before Start Of Treatment, And After 4 And 12 hrs

	Before Start Of Treatment	After 4 hrs Of Treatment	After 12 hrs Of Treatment
ST2 (NPX) median (IQR)	5.15 (5.19–5.87)	5.69 (4.92–6.20)*	5.99 (5.21–6.35)*
pCO2 kPa median (IQR)	8.75 (7.78–10.50)	8.10 (6.55–8.70)*	7.40 (6.40–8.70)*
pH median (QR)	7.28 (7.24–7.36)	7.37 (7.34–7.40)*	7.39 (7.34–7.43)*

Notes: *Difference between values before the start of treatment and after 4 hrs or 12 hrs of treatment is significant, analysed with Wilcoxon parade rank test.

Abbreviations: IQR, interquartile range; NPX, normalized protein expression (for details, se olink.com).