Baseline characteristics of the patients
Patients demographics and clinical settings are shown in Table 1. No differences in age, gender, weight, and transmission route (P > 0.05) were found in PJP and CMV-P cohorts. In terms of inflammation, there was no significant difference in leukocyte counts (P = 0.22) and C-reactive protein (P = 0.75) between both groups, however, the neutrophil percentage in PJP patients was higher than in CMV-P group (P = 0.01), and the lymphocyte percentage in CMV-P was higher than in PJP group (P = 0.02). In addition, the HIV viral loads were significantly higher in PJP than in CMV-P (P = 0.02) while no differences were found in CD4+T cell counts (P = 0.28), CD8+ T cell counts (P = 0.54), and CD4/CD8 ratio (P = 0.48) between two cohorts.
Table1 Characteristics of AIDS patients with Pneumocystis jirovecii pneumonia and cytomegalovirus pneumonia.
|
PJP (n = 78)
|
CMV-P (n = 34)
|
P-value
|
Age (years), median (IQR)
|
33 (29, 45.25)
|
38 (29, 48.25)
|
0.12
|
Male, n (%)
|
75 (96.15)
|
33 (97.06)
|
0.81
|
Weight (kg), mean(SD)
|
64.05 (11.20)
|
62.82 (9.99)
|
0.58
|
Transmission route, n (%)
|
|
|
0.41
|
Homosexual
|
25 (32.05)
|
12 (35.29)
|
|
Heterosexual
|
9 (11.54)
|
1 (2.94)
|
|
Intravenous drug
|
1 (1.28)
|
0
|
|
Blood transfusion
|
3 (3.85)
|
1 (2.94)
|
|
Unknown
|
40 (51.28)
|
20 (58.82)
|
|
Leukocyte count (×109/L), median (IQR)
|
5.50 (3.64, 8.57)
|
4.52 (3.20, 6.85)
|
0.22
|
Neutrophil percentage(%), median (IQR)
|
79.39 (61.08, 86.42)
|
68.15 (56.18, 79.50)
|
0.01
|
Lymphocyte percentage (%), median (IQR)
|
11.91 (8.48, 19.54)
|
18.20 (12.10, 27.24)
|
0.02
|
CRP (mg/L), median (IQR)
|
12.65 (3.40, 36.23)
|
13.30 (2.70, 35.23)
|
0.75
|
HIV viral load log10 (copy/ml), median (IQR)
|
5.50 (5.17, 5.93)
|
5.19 (4.51, 5.67)
|
0.02
|
CD4 T cell count (cells/μl), median (IQR)
|
22 (9, 47.75)
|
22.50 (13, 77)
|
0.28
|
CD8 T cell count (cells/μl), median (IQR)
|
458 (329.75, 679)
|
485.50 (323.75, 779.50)
|
0.54
|
CD4/CD8 ratio (%), median (IQR)
|
0.05 (0.02, 0.10)
|
0.06 (0.02, 0.16)
|
0.48
|
PJP = Pneumocystis jirovecii pneumonia, CMV-P = cytomegalovirus pneumonia, CRP = C-reactive protein, IQR = interquartile range, SD = standard deviation.
CT features between PJP and CMV-P
Thoracic CT features of the 112 patients are shown in Table 2 and Table 3. There was no significant difference between PJP and CMV-P in the time between clinical onset and CT examination (6 days in PJP and 5 days in CMV-P, P = 0.99), as well as the time between CT and bronchoscopy (5 days in PJP and 3.50 days in CMV-P, P = 0.07). GGO was common in AIDS patients with PJP and CMV-P (Fig. 1a and Fig. 2a), with 100% penetrance in both cohorts. Contrastingly, the frequency of cavity was rare in PJP (2.56%) and CMV-P (0%). No significant differences were found in mosaic perfusion, crazy-paving pattern, TIB, bronchial wall thickening, reticulation, LN enlargement, cavity, and cyst between both cohorts (all P > 0.05). As shown in Table 3, the frequency of consolidation and nodules were significantly higher in patients with CMV-P than in those with PJP (P = 0.01 and P<0.001, respectively) (Fig. 1a, 1b and Fig. 2b, 2c). Compared to patients with PJP, large nodules with perilymphatic distribution were not found in any of patients with CMV-P. In addition, halo sign was more frequent in CMV-P (32.35%) than in PJP (11.54%). To identify the significant parameters that distinguished PJP from CMV-P, binary logistic regression analyses were conducted and 2 significant parameters were identified; consolidation (P = 0.020; OR: 3.015; 95% CI: 1.190–7.637) and nodules (P < 0.001; OR: 9.298; 95% CI: 3.191–27.095) (Table 4). Combining consolidation and nodules, the AUC for distinguishing PJP from CMV-P was 0.769.
Table 2 Thoracic CT features without significant differently frequency.
|
PJP (n = 78)
|
CMV-P (n = 34)
|
P-value
|
Time between clinical onset and CT examination (days), median (IQR)
|
6 (3, 10)
|
5 (3, 13.25)
|
0.99
|
Time between CT and bronchoscopy (days), median (IQR)
|
5 (3, 7)
|
3.50 (2, 6)
|
0.07
|
GGO, n (%)
|
100
|
100
|
NS
|
Mosaic perfusion, n (%)
|
25 (32.05)
|
10 (29.41)
|
0.78
|
Crazy-paving pattern, n (%)
|
7 (8.97)
|
3 (8.82)
|
0.98
|
Cons/GGO predominance, n (%)
|
|
|
0.82
|
Cons
|
2 (2.56)
|
2(5.88)
|
|
GGO
|
75 (96.15)
|
32 (94.12)
|
|
Equal
|
1 (1.28)
|
0
|
|
Cons/GGO distribution, n (%)
|
|
|
0.06
|
Segmental
|
6 (7.69)
|
5 (14.71)
|
|
Non-segmental
|
6 (7.69)
|
7 (20.59)
|
|
Lobular
|
66 (84.62)
|
22 (64.71)
|
|
TIB, n (%)
|
5 (6.41)
|
5 (14.71)
|
0.16
|
Bronchial wall thickening, n (%)
|
27 (34.62)
|
16 (47.06)
|
0.21
|
Reticulation, n (%)
|
45 (57.69)
|
18 (52.94)
|
0.64
|
LN enlargement, n (%)
|
5 (6.41)
|
5 (14.71)
|
0.16
|
Pleural effusion, n (%)
|
8 (10.26)
|
8 (23.53)
|
0.07
|
Cavity, n (%)
|
2 (2.56)
|
0
|
0.35
|
Cyst, n (%)
|
13 (16.67)
|
4 (11.76)
|
0.51
|
IQR = interquartile range, PJP = Pneumocystis jirovecii pneumonia, CMV-P = cytomegalovirus pneumonia, GGO = ground-glass opacity, Cons = consolidation, TIB = tree-in-bud sign, LN = lymph node, NS = no significance.
Table 3 Thoracic CT features with significant differentiating frequency.
|
PJP (n = 78)
|
CMV-P (n = 34)
|
P-value
|
Nodule, n (%)
|
7 (8.97)
|
16 (47.06)
|
<0.001
|
Nodule-size, n (%)
|
|
|
<0.001
|
Micro
|
1 (1.28)
|
5 (14.71)
|
|
Small
|
5 (6.41)
|
11 (32.35)
|
|
Large
|
1 (1.28)
|
0
|
|
Nodule-distribution, n (%)
|
|
|
<0.001
|
Centrilobular
|
3 (3.85)
|
8 (23.53)
|
|
Perilymphatic
|
1 (1.28)
|
0
|
|
Random
|
3 (3.85)
|
8(23.53)
|
|
Consolidation, n (%)
|
28 (35.90)
|
21 (61.77)
|
0.01
|
Halo sign, n (%)
|
9 (11.54)
|
11 (32.35)
|
0.01
|
Data are presented as numbers of patients, with percentages in parentheses. PJP = Pneumocystis jirovecii pneumonia, CMV-P = cytomegalovirus pneumonia.
Table 4 The results of binary logistic regression analysis.
HRCT features
|
B value
|
Wald value
|
Odds ratio
|
P-value
|
95% Cl
|
AUC
|
Nodules
|
2.230
|
16.696
|
9.298
|
<0.001
|
3.191–27.095
|
|
Consolidation
|
1.104
|
5.417
|
3.015
|
0.020
|
1.190–7.637
|
0.769
|
constant
|
-1.919
|
24.951
|
0.147
|
<0.001
|
|
|
HRCT: High-resolution computed tomography, CI = confidence intervals, AUC = area under the receiver operating
Correlation analysis of nodules’ occurrence between PJP and CMV-P patients
We next performed correlation analysis of nodules’ and consolidations’ occurrence between PJP and CMV-P patients (Table 5). Results showed that nodules’ occurrence were positively correlated with CD4+T cell count, CD8+T cell count and CD4/CD8 ratio, while no significant correlations were found with CRP, neutrophil percentage and HIV viral load in CMV-P patients. Among patients with PJP, no significant correlations were observed between nodules’ occurrence or any other clinical indicators. Similarly, there were no significant correlations between consolidations’ occurrence and other clinical indicators in PJP and CMV-P patients (data were not shown).
Table 5 Correlation analysis of nodules’ occurrence between pneumocystis pneumonia and cytomegalovirus pneumonia patients.
|
PJP (n = 78)
|
CMV-P (n = 34)
|
Variable
|
R-value
|
P-value
|
R-value
|
P-value
|
CD4+T cell count
|
0.159
|
0.163
|
0.545
|
0.001
|
CD8+T cell count
|
0.111
|
0.332
|
0.392
|
0.022
|
CD4/CD8 ratio
|
0.104
|
0.366
|
0.503
|
0.002
|
CRP
|
-0.059
|
0.607
|
0.182
|
0.304
|
Neutrophil percentage
|
0.02
|
0.859
|
-0.233
|
0.186
|
HIV viral load log10
|
0.08
|
0.488
|
-0.27
|
0.122
|
PJP = Pneumocystis jirovecii pneumonia, CMV-P = pneumocystis pneumonia, CRP = C-reactive protein