Demographics, clinical characteristics, and clinical outcomes of patients were summarized in Table 2 according to the overall cohort, first and second level cohorts. Even with the exclusion of patients due to delayed measurement of PCT, first and second level cohorts were still similar to the overall cohort in terms of clinical characteristics, comorbidities profile, and clinical outcomes.
Table 2
Demographics and clinical characteristics of the study cohort.
Characteristics
|
Overall
n (%)
|
First level
n (%)
|
Second level
n (%)
|
Total
|
319 (100.0)
|
276 (100.0)
|
237 (100.0)
|
Age, years: Mean (SD)
|
56 (13.6)
|
54.8 (13.7)
|
55.0 (13.7)
|
Gender: Female
|
111 (34.8)
|
102 (37.0)
|
84 (35.4)
|
Race
|
|
|
|
Malay
|
168 (52.7)
|
147 (53.3)
|
122 (51.5)
|
Chinese
|
68 (21.3)
|
54 (19.6)
|
46 (19.4)
|
Indian
|
52 (16.3)
|
48 (17.4)
|
44 (18.6)
|
Others
|
31 (9.7)
|
27 (9.8)
|
25 (10.5)
|
Comorbidities profile
|
|
|
|
Hypertension: Yes
|
179 (56.1)
|
158 (57.2)
|
135 (57.0)
|
Chronic Cardiac Disease: Yes
|
64 (20.1)
|
54 (19.6)
|
46 (19.4)
|
Chronic Pulmonary Disease: Yes
|
10 (3.1)
|
8 (2.9)
|
7 (3.0)
|
Asthma: Yes
|
14 (4.4)
|
13 (4.7)
|
10 (4.2)
|
Diabetes Mellitus: Yes
|
147 (46.1)
|
128 (46.4)
|
110 (46.4)
|
Pre-existing Renal Disease: Yes
|
73 (22.9)
|
56 (20.3)
|
46 (19.4)
|
Chronic Liver Disease: Yes
|
3 (0.9)
|
2 (0.7)
|
2 (0.8)
|
Dementia: Yes
|
3 (0.9)
|
3 (1.1)
|
2 (0.8)
|
Chronic Neurological Conditions: Yes
|
16 (5.0)
|
13 (4.7)
|
10 (4.2)
|
Connective Tissue Disease: Yes
|
7 (2.2)
|
7 (2.5)
|
5 (2.1)
|
HIV/AIDS: Yes
|
2 (0.6)
|
1 (0.4)
|
1 (0.4)
|
Malignancy: Yes
|
11 (3.4)
|
9 (3.3)
|
8 (3.4)
|
Current Smoking: Yes
|
9 (2.8)
|
5 (1.8)
|
4 (1.7)
|
Obesity: Yes
|
17 (5.3)
|
17 (6.2)
|
16 (6.8)
|
Others: Yes
|
81 (25.4)
|
67 (24.3)
|
51 (21.5)
|
COVID-19 severity when procalcitonin first sent
|
|
|
|
Category 4
|
254 (79.6)
|
217 (78.6)
|
181 (76.4)
|
Category 5
|
65 (20.4)
|
59 (21.4)
|
56 (23.6)
|
4C mortality score
|
|
|
|
0-3 (low-risk in-hospital mortality)
|
16 (5.0)
|
15 (5.4)
|
13 (5.5)
|
4-8 (intermediate-risk in-hospital mortality)
|
117 (36.7)
|
105 (38.0)
|
87 (36.7)
|
9-14 (high-risk in-hospital mortality)
|
145 (45.5)
|
124 (44.9)
|
107 (45.1)
|
15-21 (very high-risk in-hospital mortality)
|
41 (12.8)
|
32 (11.6)
|
30 (12.7)
|
Steroid use: Yes
|
297 (93.1)
|
257 (93.1)
|
219 (92.4)
|
Bloodstream infection: Yes
|
35 (11.0)
|
28 (13.0)
|
25 (13.4)
|
Clinical outcomes
|
|
|
|
ICU admission: Yes
|
143 (44.8)
|
129 (46.7)
|
120 (50.6)
|
NIV use: Yes
|
65 (20.4)
|
60 (21.7)
|
57 (24.1)
|
Duration of NIV use, days, median (IQR)
|
3 (1.8, 5.3)
|
3 (1.8, 5.3 )
|
3 (1, 5)
|
Mechanical ventilation: Yes
|
101 (31.7)
|
89 (32.2)
|
85 (35.9)
|
Duration of mechanical ventilation use, days, median (IQR)
|
6 (4, 12)
|
7 (4, 12)
|
7 (4, 12)
|
Organizing pneumonia
|
|
|
|
Yes
|
135 (42.3)
|
118 (42.8)
|
102 (43.0)
|
No
|
26 (8.2)
|
21 (7.6)
|
19 (8.0)
|
CT scan not done
|
158 (49.5)
|
137 (49.6)
|
116 (48.9)
|
Thrombotic event: Yes
|
83 (26.0)
|
69 (25.0)
|
62 (26.2)
|
All-cause mortality: Yes
|
71 (22.3)
|
59 (21.4)
|
55 (23.2)
|
Due to severe COVID-19 pneumonia
|
48 (67.6)
|
43 (72.9)
|
39 (70.9)
|
Due to thrombotic event
|
8 (11.3)
|
7 (16.3)
|
7 (17.9)
|
Due to comorbid
|
7 (9.8)
|
4 (9.3)
|
4 (10.3)
|
Due to bacterial infections
|
8 (11.3)
|
5 (11.6)
|
5 (12.8)
|
Bacteremia
|
3 (4.2)
|
1 (2.3)
|
1 (2.6)
|
Intra-abdominal infection
|
1 (1.4)
|
0 (0)
|
0 (0)
|
Necrotizing fasciitis
|
1 (1.4)
|
1 (2.3)
|
1 (2.6)
|
Non-specified site
|
1 (1.4)
|
0 (0)
|
0 (0)
|
Non-bacteremia
|
5 (7.0)
|
4 (9.3)
|
4 (10.3)
|
Pulmonary infection
|
2 (2.8)
|
1 (2.3)
|
1 (2.6)
|
Intra-abdominal infection
|
1 (1.4)
|
1 (2.3)
|
1 (2.6)
|
Non-specified site
|
2 (2.8)
|
2 (4.7)
|
2 (5.1)
|
Column percentages are reported in parenthesis for categorical variables; mean and standard deviation are reported for continuous variable age; median and interquartile range are reported for continuous variables duration of non-invasive ventilation and mechanical ventilation.
Abbreviations: CT, computed tomography; HIV/AIDS, human immunodeficiency virus/acquired immunodeficiency syndrome; ICU; intensive care unit; NIV, non-invasive ventilation.
Determination of the optimal cut-point
In the determination of optimal cut-points for PCT, we included clinical outcomes, such as all-cause mortality, mechanical ventilation, thrombotic events, ICU admissions, and bacterial infection among moderate to severe COVID-19 patients. Table 3 and Table 4 present various performance indexes and optimal cut-points for PCT with regards to the aforementioned clinical outcomes based on PCT levels measured within 5 days and 3 days following admission.
For PCT levels measured within 5 days following admission, the optimal cut-points for PCT were found to be 0.20 ng/mL for all-cause mortality, 0.33 ng/mL for mechanical ventilation, 1.21 ng/mL for thrombotic events, 0.09 ng/mL for ICU admission dan 1.2 ng/mL for bacterial infection (Table 3). Highest sensitivity was found in all-cause mortality (0.8136) for PCT cut-point of 0.20 ng/mL. For PCT levels measured within 3 days following admission, the optimal cut-points for PCT were found to be 0.20 ng/mL for all-cause mortality, 0.21 ng/mL for mechanical ventilation, 1.21 ng/mL for thrombotic events, 0.07 ng/mL for ICU admission dan 1.25 ng/mL for bacterial infection (Table 4). Highest sensitivity was also found in all-cause mortality (0.8364) for PCT cut-point of 0.20 ng/mL.
As 0.2 ng/mL appeared to be the optimal cut-point in all-cause mortality for PCT levels measured within 5 days and 3 days following admission, and in mechanical ventilation for PCT levels measured within 3 days following admission, therefore, 0.2 ng/mL was selected as the final PCT cut-point in the matching analysis using propensity scores. The PCT of 0.2 ng/mL represented the optimal cut-point for the two clinically important outcomes, all-cause mortality and mechanical ventilation, especially for moderate to severe COVID-19 patients with PCT measured within 3 days following admission.
Table 3
Optimal cut-off PCT values (within 5 days from admission)
Cut-point and Indexes
|
All-cause mortality
|
Mechanical ventilation
|
Thrombotic
events
|
ICU
admission
|
Bacterial infection culture
|
Number of patients
|
276
|
276
|
276
|
276
|
216
|
Positive cases
|
59
|
89
|
69
|
129
|
28
|
Negative cases
|
217
|
187
|
207
|
147
|
188
|
AUC
|
0.7741
|
0.7773
|
0.6666
|
0.7223
|
0.6444
|
Optimal cut-point (ng/ml)
|
0.20
|
0.33
|
1.21
|
0.09
|
1.2
|
Accuracy
|
0.6703
|
0.7391
|
0.7536
|
0.6848
|
0.7454
|
Sensitivity
|
0.8136
|
0.6742
|
0.4203
|
0.7442
|
0.5357
|
Specificity
|
0.6313
|
0.7701
|
0.8647
|
0.6327
|
0.7766
|
Precision
|
0.3750
|
0.5825
|
0.5088
|
0.6400
|
0.2632
|
TP
|
48
|
60
|
29
|
96
|
15
|
FN
|
11
|
29
|
40
|
33
|
13
|
FP
|
54
|
43
|
28
|
43
|
42
|
TN
|
93
|
144
|
179
|
144
|
146
|
TP: True positive; FN: False negative; FP: False positive; TN: True negative; AUC: Area under Curve |
Table 4
Optimal cut-off PCT values (within 3 days from admission)
Cut-point and Indexes
|
All-cause mortality
|
Mechanical ventilation
|
Thrombotic
events
|
ICU
admission
|
Bacterial infection culture
|
Number of patients
|
237
|
237
|
237
|
237
|
186
|
Positive cases
|
55
|
85
|
62
|
120
|
25
|
Negative cases
|
182
|
152
|
175
|
117
|
161
|
AUC
|
0.7812
|
0.7676
|
0.6711
|
0.7365
|
0.6465
|
Optimal cut-point (ng/ml)
|
0.20
|
0.21
|
1.21
|
0.07
|
1.25
|
Accuracy
|
0.6667
|
0.7046
|
0.7468
|
0.7046
|
0.7419
|
Sensitivity
|
0.8364
|
0.7528
|
0.4355
|
0.8333
|
0.5600
|
Specificity
|
0.6154
|
0.6776
|
0.8571
|
0.5726
|
0.7702
|
Precision
|
0.3966
|
0.5663
|
0.5192
|
0.6667
|
0.2745
|
TP
|
46
|
64
|
27
|
100
|
14
|
FN
|
9
|
21
|
35
|
20
|
11
|
FP
|
70
|
49
|
25
|
50
|
37
|
TN
|
112
|
103
|
150
|
67
|
124
|
TP: True positive; FN: False negative; FP: False positive; TN: True negative; AUC: Area under Curve |
Propensity scores matching analysis
To assess the prognostic value of the optimal cut-point, the analysis focused on those who had their PCT levels measured within 3 days following admission. Moreover, the selected cut-point of 0.2 ng/mL was optimal for all-cause mortality and mechanical ventilation among those with PCT levels measured within 3 days following admission. Table 5 summarizes the covariate differences according to the selected optimal cut-point for PCT among 237 patients. Significant differences were identified for age (p=0.0122), COVID-19 disease stage (p<0.0001), days of illness before admission (p=0.0036), SPO2 under room temperature (RA) (p=0.0005), Glasgow Coma Scale (GCS) (p<0.0001), urea (p<0.0001), C-reactive protein (CRP) (p<0.0001), white blood cells count (WBC) (p=0.0003), absolute neutrophil count (ANC) (p<0.0001), number of comorbidities (p<0.0001), presence of hypertension (p=0.0007), chronic cardiac diseases (p=0.0018), diabetes mellitus (DM) (p=0.0036), pre-existing renal disease (p<0.0001) and malignancy (p=0.0327).
Table 6 presents the odds ratio (OR) with regards to various clinical outcomes based on the optimal cut-point of 0.2 ng/mL for PCT. Prior to matching, our analysis found that patients with PCT level above 0.2 ng/mL were associated with significantly higher risk in all-cause mortality (OR: 8.178, 95%CI: 3.770 - 17.738, p<0.0001), mechanical ventilation (OR: 5.861, 95%CI: 3.229 – 10.637, p<0.0001), non-invasive ventilation (OR: 2.898, 95%CI: 1.541 – 5.541, p=0.0010), ICU admission (OR: 4.166, 95%CI: 2.422 – 7.166, p<0.0001) and thrombotic events (OR: 2.158, 95%CI: 1.190 – 3.915, p=0.0013). Besides, patients with PCT levels above 0.2 ng/mL also experienced significantly longer days of mechanical ventilation (p<0.0106) and length of hospital stay (p<0.0001). Table 7 shows the mortality and causes of death before propensity score matching.
Table 5
Demographics, clinical characteristics & baseline laboratory findings, and comorbidity profile of COVID-19 patients according to procalcitonin level.
Variables
|
Category
|
PCT < 0.2 (ng/ml)
|
PCT ≥ 0.2 (ng/ml)
|
p-value
|
(n=121)
|
(n=116)
|
Demographics
|
|
|
|
|
Gender
|
Female
|
42 (34.7)
|
42 (36.2)
|
0.8097
|
Age (years)
|
Mean (SD)
|
52.8 (12.6)
|
57.3 (14.4)
|
0.0122
|
Age groups (years)
|
< 50
|
45 (37.2)
|
33 (28.4)
|
0.0945
|
|
50 – 59
|
38 (31.4)
|
28 (24.1)
|
|
|
60 – 60
|
23 (19.0)
|
34 (29.3)
|
|
|
≥ 70
|
15 (12.4)
|
21 (18.1)
|
|
Ethnicity
|
Malay
|
60 (62.3)
|
62 (53.4)
|
0.0675
|
|
Chinese
|
22 (18.2)
|
24 (20.7)
|
|
|
Indian
|
20 (16.5)
|
24 (20.7)
|
|
|
Others
|
19 (15.7)
|
6 (5.2)
|
|
Clinical characteristics & baseline laboratory
|
|
|
Severity of disease
|
Category 4
|
111 (91.7)
|
70 (60.3)
|
< 0.0001
|
|
Category 5
|
10 (8.3)
|
46 (39.7)
|
|
Days of illness
|
Mean (SD)
|
6.5 (3.0)
|
5.3 (3.1)
|
0.0036
|
SPO2 under RA (%)
|
< 92%
|
98 (81.0)
|
111 (95.7)
|
0.0005
|
|
≥ 92%
|
23 (19.0)
|
5 (4.3)
|
|
RR, bpm
|
< 20
|
13 (10.7)
|
14 (12.1)
|
0.2520
|
|
20 – 29
|
93 (76.9)
|
79 (68.1)
|
|
|
≥ 30
|
15 (12.4)
|
23 (19.8)
|
|
GCS
|
<15
|
11 (9.1)
|
50 (43.1)
|
<0.0001
|
|
15
|
110 (90.9)
|
66 (56.9)
|
|
Urea, mmol/dL
|
< 7
|
87 (71.9)
|
31 (26.7)
|
<0.0001
|
|
7 – 14
|
29 (24.0)
|
31 (26.7)
|
|
|
> 14
|
5 (4.1)
|
54 (46.6)
|
|
CRP, mg/dL
|
< 5
|
49 (40.5)
|
8 (6.9)
|
<0.0001
|
|
5 – 9.9
|
31 (25.6)
|
69 (59.5)
|
|
|
≥ 10
|
41 (33.9)
|
39 (33.6)
|
|
WBC (x10^12/L)
|
Mean (SD)
|
8.56 (3.88)
|
10.90 (5.80)
|
0.0003
|
ANC (x10^9/L)
|
Mean (SD)
|
6.75 (3.81)
|
9.26 (5.53)
|
<0.0001
|
Comorbidity profile
|
|
|
|
|
No. of comorbidity
|
0
|
67 (55.4)
|
33 (28.4)
|
<0.0001
|
|
1
|
42 (34.7)
|
33 (28.4)
|
|
|
≥ 2
|
12 (9.9)
|
50 (43.1)
|
|
Hypertension
|
Yes
|
56 (46.3)
|
79 (68.1)
|
0.0007
|
Chronic cardiac disease (excluding HPT)
|
Yes
|
14 (11.6)
|
32 (27.6)
|
0.0018
|
Asthma
|
Yes
|
6 (5.0)
|
4 (3.4)
|
0.7491
|
Chronic pulmonary disease (excluding asthma)
|
Yes
|
3 (2.5)
|
4 (3.4)
|
0.7174
|
Diabetes Mellitus
|
Yes
|
45 (37.2)
|
65 (56.0)
|
0.0036
|
Pre-existing renal disease
|
Yes
|
5 (4.1)
|
41 (35.3)
|
<0.0001
|
Stage 2
|
|
2 (40.0)
|
0
|
|
Stage 3
|
|
0
|
6(14.6)
|
|
Stage 4
|
|
2 (40.0)
|
8 (19.5)
|
|
Stage 5
|
|
1 (20.0)
|
27 (65.9)
|
|
HIV/AIDS
|
Yes
|
1
|
0
|
n.a
|
Malignancy
|
Yes
|
1 (0.8)
|
7 (6.0)
|
0.0327
|
Smoking
|
Yes, current
|
1 (0.8)
|
3 (2.6)
|
n.a
|
Obesity (> 30kg/m2)
|
Yes
|
7 (5.8)
|
9 (7.8)
|
0.5449
|
Chronic liver disease
|
Yes
|
0
|
2
|
n.a
|
Dementia
|
Yes
|
0
|
2
|
n.a
|
Chronic neurological disease
|
Yes
|
2 (1.7)
|
8 (6.9)
|
0.0555
|
Connective tissue disease
|
Yes
|
2 (1.7)
|
3 (2.6)
|
0.6783
|
Abbreviations: ANC, absolute neutrophil count; CRP, C-reactive protein; GCS, Glasgow coma scale; HIV/AIDS, human immunodeficiency virus/acquired immunodeficiency syndrome; PCT, procalcitonin; RR, respiratory rate; RA, room air; SD, standard deviation; WBC, white blood cell count. |
Table 6
Clinical outcomes before propensity score matching.
Clinical outcomes
|
Category
|
PCT level (ng/ml)
|
OR (95% CI)
|
|
PCT < 0.2
(n=121)
|
PCT ≥ 0.2
(n=116)
|
p-value
|
Procalcitonin level
|
Mean (SD)
|
0.0674 (0.0331)
|
6.002 (11.556)
|
n.a
|
<0.0001
|
All-cause mortality
|
Yes
|
9 (7.4)
|
46 (39.7)
|
8.178 (3.770 – 17.738)
|
<0.0001
|
|
No
|
112 (92.6)
|
70 (60.3)
|
|
|
Mechanical ventilation
|
Yes
|
21 (17.4)
|
64 (55.2)
|
5.861 (3.229 – 10.637)
|
<0.0001
|
|
No
|
100 (82.6)
|
52 (44.8)
|
|
|
Non-invasive ventilation
|
Yes
|
18 (14.9)
|
39 (33.6)
|
2.898 (1.541 – 5.541)
|
0.0010
|
|
No
|
103 (85.1)
|
77 (66.4)
|
|
|
ICU admission
|
Yes
|
41 (33.9)
|
79 (68.1)
|
4.166 (2.422 – 7.166)
|
<0.0001
|
|
No
|
80 (66.1)
|
37 (31.9)
|
|
|
Thrombotic events
|
Yes
|
23 (19.0)
|
39 (33.6)
|
2.158 (1.190 – 3.915)
|
0.0113
|
|
No
|
98 (81.0)
|
77 (66.4)
|
|
|
Positive culture
|
Yes
|
68 (89.5)
|
93 (84.5)
|
0.643 (0.263 – 1.578)
|
0.3354
|
|
No
|
8 (10.5)
|
17 (15.5)
|
|
|
Days of mechanical ventilation
|
Median (IQR)
|
5 (4 – 6)
|
9 (5 – 12.3)
|
n.a
|
0.0106
|
Days of non-invasive ventilation
|
Median (IQR)
|
3 (2 - 4)
|
3 (1 - 6)
|
|
0.8071
|
Length of hospital stay, days
|
Median (IQR)
|
11 (9 – 14)
|
16 (11.3 – 20.8)
|
n.a
|
<0.0001
|
Abbreviations: CI, confidence interval; ICU; intensive care unit; IQR, interquartile range; MV, mechanical ventilation; NIV, non-invasive ventilation; OR, odds ratio; PCT, procalcitonin. |
Table 7
Mortality and causes of death before propensity score matching
Mortality outcomes
|
Cases (%)
|
Total number of deaths
|
55
|
Cause of death
|
|
Severe COVID-19 pneumonia
|
39 (70.9)
|
Bacterial infection
|
5 (9.1)
|
Bacteremia
|
1
|
Non-bacteremia
|
4
|
Thrombotic event
|
7 (12.7)
|
Comorbidity
|
4 (7.3)
|
As the relative risk of patients categorized based on the optimal cut-point could be confounded by covariates that were significantly different, a propensity score matching was performed with the aforementioned covariates to derive two comparable arms for further analysis. The propensity score matching eventually identified 90 patients with balanced demographics, clinical characteristics, comorbidities profile, and laboratory findings except for urea (p=0.0139) and CRP (p<0.0001) as shown in Table 8. Subsequent analyses showed that patients with PCT above 0.2 ng/mL were associated with a significantly higher risk in all-cause mortality (OR: 4.629, 95%CI: 1.387 – 15.449, p=0.0127), and marginally higher risk for non-invasive ventilation (OR: 2.667, 95% CI: 1.039 – 6.847, p=0.0415). Besides, patients with PCT above 0.2 ng/mL tended to experience longer days of mechanical ventilation (p=0.0213) as summarized in Table 9. There was no significant association between PCT level and risk of mechanical ventilation (OR; 2.010, 95% CI; 0.828 - 4.878, p = 0.1229) after being matched for covariate differences.
Table 8
Demographics, clinical characteristics & baseline laboratory findings and comorbidity profile of COVID-19 patients according to procalcitonin level after propensity score matching
Variables
|
Category
|
PCT < 0.2
|
PCT ≥ 0.2
|
p-value
|
(n=45)
|
(n=45)
|
Demographics
|
|
|
|
|
Gender
|
Female
|
17 (37.8)
|
17 (37.8)
|
1.0000
|
Age
|
Mean (SD)
|
55.1 (11.2)
|
53.4 (13.1)
|
0.5070
|
Age groups
|
< 50
|
13 (28.9)
|
16 (35.6)
|
0.7838
|
|
50 – 59
|
14 (31.1)
|
15 (33.3)
|
|
|
60 – 60
|
13 (28.9)
|
9 (20.0)
|
|
|
≥ 70
|
5 (11.1)
|
5 (11.1)
|
|
Ethnicity
|
Malay
|
22 (48.9)
|
27 (60.0)
|
0.6236
|
|
Chinese
|
9 (20.0)
|
7 (15.6)
|
|
|
Indian
|
8 (17.8)
|
8 (17.8)
|
|
|
Others
|
6 (13.3)
|
3 (6.7)
|
|
Clinical characteristics & baseline laboratory
|
|
|
Severity of disease
|
Category 4
|
35 (77.8)
|
37 (82.2)
|
0.5982
|
|
Category 5
|
10 (22.2)
|
8 (17.8)
|
|
Days of illness
|
Mean (SD)
|
5.7 (2.8)
|
5.6 (3.0)
|
0.8852
|
SPO2 under RA (%)
|
< 92%
|
38 (84.4)
|
42 (93.3)
|
0.1797
|
|
≥ 92%
|
7 (15.6)
|
3 (6.7)
|
|
RR, bpm
|
< 20
|
5 (11.1)
|
4 (8.9)
|
|
|
20 – 29
|
33 (73.3)
|
31 (68.9)
|
|
|
≥ 30
|
7 (15.6)
|
10 (22.2)
|
|
GCS
|
<15
|
9 (20.0)
|
11 (24.4)
|
0.6121
|
|
15
|
36 (80.0)
|
34 (75.6)
|
|
Urea, mmol/dL
|
< 7
|
24 (53.3)
|
20 (44.4)
|
0.0139
|
|
7 – 14
|
17 (37.8)
|
10 (22.2)
|
|
|
> 14
|
4 (8.9)
|
15 (33.3)
|
|
CRP, mg/dL
|
< 5
|
17 (37.8)
|
1 (2.2)
|
< 0.0001
|
|
5 – 9.9
|
13 (28.9)
|
15 (33.3)
|
|
|
≥ 10
|
15 (33.3)
|
29 (64.4)
|
|
WBC (x10^12/L)
|
Mean (SD)
|
9.79 (4.26)
|
10.69 (6.09)
|
0.4148
|
ANC (x10^9/L)
|
Mean (SD)
|
7.89 (4.32)
|
8.74 (5.82)
|
0.4328
|
Comorbidity profile
|
|
|
|
|
No. of comorbidity
|
0
|
15 (33.3)
|
15 (33.3)
|
0.9654
|
|
1
|
19 (42.2)
|
18 (40.0)
|
|
|
≥ 2
|
11 (24.4)
|
12 (26.7)
|
|
Hypertension
|
Yes
|
24 (53.3)
|
27(60.0)
|
0.5234
|
Chronic cardiac disease (excluding HPT)
|
Yes
|
12 (26.7)
|
12 (26.7)
|
1.0000
|
Asthma
|
Yes
|
1 (2.2)
|
0
|
n.a
|
Chronic pulmonary disease (excluding asthma)
|
Yes
|
1 (2.2)
|
2 (4.4)
|
n.a
|
Diabetes Mellitus
|
Yes
|
24 (53.3)
|
21 (46.7)
|
0.5271
|
Pre-existing renal disease
|
Yes
|
5 (11.1)
|
9 (20.0)
|
0.2447
|
Stage 2
|
|
2
|
0
|
|
Stage 3
|
|
0
|
1
|
|
Stage 4
|
|
2
|
0
|
|
Stage 5
|
|
1
|
8
|
|
HIV/AIDS
|
Yes
|
0
|
0
|
n.a
|
Malignancy
|
Yes
|
1 (2.2)
|
0
|
n.a
|
Smoking
|
Yes, current
|
0
|
2 (4.4)
|
n.a
|
Obesity (> 30kg/m2)
|
Yes
|
2 (4.4)
|
4 (8.9)
|
0.6766
|
Chronic liver disease
|
Yes
|
0
|
1 (2.2)
|
|
Dementia
|
Yes
|
0
|
0
|
|
Chronic neurological disease
|
Yes
|
2 (4.4)
|
1 (2.2)
|
|
Connective tissue disease
|
Yes
|
2 (4.4)
|
2 (4.4)
|
|
Abbreviations: ANC, absolute neutrophil count; CRP, C-reactive protein; GCS, Glasgow Coma Scale; HIV/AIDS, human immunodeficiency virus/acquired immunodeficiency syndrome; PCT, procalcitonin; RR, respiratory rate; RA, room air; SD, standard deviation; WBC, white blood cell count. |
Table 9
Clinical outcomes after propensity score matching.
Clinical outcomes
|
Category
|
PCT level
|
OR (95% CI)
|
|
PCT < 0.2
(n=45)
|
PCT ≥ 0.2
(n=45)
|
p-value
|
Procalcitonin level
|
Mean (SD)
|
0.068 (0.033)
|
4.849 (11.624)
|
n.a
|
0.0084
|
All-cause mortality
|
Yes
|
4 (8.9)
|
14 (31.1)
|
4.629 (1.387 – 15.449)
|
0.0127
|
|
No
|
41 (91.1)
|
31 (68.9)
|
|
|
Mechanical ventilation
|
Yes
|
12 (26.7)
|
19 (42.2)
|
2.010 (0.828 – 4.878)
|
0.1229
|
|
No
|
33 (73.3)
|
26 (57.8)
|
|
|
Non-invasive ventilation
|
Yes
|
9 (20.0)
|
18 (40.0)
|
2.667 (1.039 – 6.847)
|
0.0415
|
|
No
|
36 (80.0)
|
27 (60.0)
|
|
|
ICU admission
|
Yes
|
23 (51.1)
|
28 (62.2)
|
1.575 (0.681 – 3.648)
|
0.2886
|
|
No
|
22 (48.9)
|
17 (37.8)
|
|
|
Thrombotic events
|
Yes
|
10 (22.2)
|
15 (33.3)
|
1.750 (0.686 – 4.467)
|
0.2418
|
|
No
|
35 (77.8)
|
30 (66.7)
|
|
|
Positive culture
|
Yes
|
3 (10.0)
|
4 (9.5)
|
0.947 (0.196 – 4.582)
|
0.9464
|
|
No
|
27 (90.0)
|
38 (90.5)
|
|
|
Days of mechanical ventilation
|
Median (IQR)
|
5 (4 - 6)
|
8 (5 - 12)
|
n.a
|
0.0213
|
Days of non-invasive ventilation
|
Median (IQR)
|
3 (2 - 4)
|
3.5 (1 - 6)
|
n.a
|
0.7928
|
Length of hospital stay, days
|
Median (IQR)
|
13.5 (9.8 - 17)
|
15 (10 – 19.5)
|
n.a
|
0.1304
|
Abbreviations: CI, confidence interval; ICU; intensive care unit; IQR, interquartile range; MV, mechanical ventilation; NIV, non-invasive ventilation; OR, odds ratio; PCT, procalcitonin. |