Evaluations of 1611 medical records revealed 328 patients had a history of IHD and 1,283 patients had no history of IHD. Because of missing records, 28 patients of the IHD group and 65 patients of the non-IHD group were excluded from the study. Finally, data were collected from 300 patients in the IHD group and 1218 patients in the non-IHD group (Fig. 1). Of them, 882 (58.1%) patients were men. The mean age of them was 59.3 ± 15.5 years.
Demographic data and underlying disease were summarized in Table 1. There is no significant difference between the two groups regarding gender and smoking (P > 0.05). However, analysis exhibited a significant difference in age between IHD and non-IHD groups, 67.99 ± 11.17 vs. 57.14 ± 15.70 years (P < 0.001).
Table 1
descriptive analysis of demographic variables and underlying disease
variable
|
Patients with IHD
(N = 300)
|
Patients without IHD
(N = 1218)
|
P-value
|
Mean(SD)
|
N (%)
|
Mean(SD)
|
N (%)
|
Gender (male)
|
|
188
(62.6%)
|
|
694
(56.9%)
|
0.074
|
Age
|
67.99 (11.17)
|
|
57.14
(15.70)
|
|
< 0.001
|
Smoking status (YES)
|
|
33
(11%)
|
|
97
(7.9%)
|
0.088
|
Comorbidities
|
Diabetes
|
|
147
(49%)
|
|
315
(25.8%)
|
< 0.001
|
CKD
|
|
36
(12%)
|
|
48
(3.9%)
|
< 0.001
|
Chronic respiratory diseases
|
|
28
(9.4%)
|
|
109
(8.9%)
|
0.861
|
HTN
|
|
195
(65%)
|
|
408
(33.5%)
|
< 0.001
|
ESRD
|
|
18
(6%)
|
|
25
(2.1%)
|
< 0.001
|
Dialysis
|
|
17
(5.7%)
|
|
25
(2.1%)
|
0.001
|
cancer
|
|
7
(2.4%)
|
|
40
(3.3%)
|
0.611
|
CKD: Chronic kidney disease, HTN: hypertension, ESRD: end stage renal disease |
Comorbidities
Among diseases, there was no significant difference between groups regarding the history of chronic respiratory diseases and malignancies (P > 0.05). However, the history of HTN, DM, CKD, and ESRD was significantly higher in patients with IHD (P < 0.05).
Drug history
Table 2 describes the drug history of both groups in detail. Angiotensin-converting enzyme (ACE) inhibitors, beta-adrenergic blockers, calcium channel blockers (CCBs), diuretics, anti-hyperglycemic agents, angiotensin II receptor blockers (ARB), antilipemic agents, anticoagulant and anticonvulsant were significantly higher in IHD group compared to non-IHD.
Table 2
Descriptive analysis of drugs were used before flu symptoms
Drug categories
|
IHD history of patients
|
N (%)
|
P-value
|
H2 blocker
|
Patients without IHD (N = 1218)
|
784 (64.4%)
|
0.187
|
Patients with IHD (N = 300)
|
221 (73.7%)
|
ACE inhibitor
|
Patients without IHD (N = 1218)
|
21 (1.7%)
|
0.036
|
Patients with IHD (N = 300)
|
11 (3.7%)
|
Beta blocker
|
Patients without IHD (N = 1218)
|
118 (9.7%)
|
< 0.001
|
Patients with IHD (N = 300)
|
103 (34.3%)
|
calcium blocker
|
Patients without IHD (N = 1218)
|
74 (6.1%)
|
< 0.001
|
Patients with IHD (N = 300)
|
36 (12%)
|
Diuretic
|
Patients without IHD (N = 1218)
|
39 (3.2%)
|
< 0.001
|
Patients with IHD (N = 300)
|
47 (15.7%)
|
Anti-hyperglycemic
|
Patients without IHD (N = 1218)
|
64 (5.3%)
|
< 0.001
|
Patients with IHD (N = 300)
|
42 (14%)
|
LABA
|
Patients without IHD (N = 1218)
|
15 (1.2%)
|
0.274
|
Patients with IHD (N = 300)
|
7 (2.3%)
|
ICS
|
Patients without IHD (N = 1218)
|
15 (1.2%)
|
0.766
|
Patients with IHD (N = 300)
|
5 (1.7%)
|
LABA and ICS
|
Patients without IHD (N = 1218)
|
22 (1.8%)
|
0.841
|
Patients with IHD (N = 300)
|
7 (2.3%)
|
ARB
|
Patients without IHD (N = 1218)
|
203 (16.7%)
|
< 0.001
|
Patients with IHD (N = 300)
|
109 (36.3%)
|
Immunosuppressive
|
Patients without IHD (N = 1218)
|
9 (0.7%)
|
0.647
|
Patients with IHD (N = 300)
|
3 (1%)
|
Levothyroxine
|
Patients without IHD (N = 1218)
|
77 (6.3%)
|
0.845
|
Patients with IHD (N = 300)
|
21 (7%)
|
Anti-hyperlipidemic
|
Patients without IHD (N = 1218)
|
155 (12.7%)
|
< 0.001
|
Patients with IHD (N = 300)
|
126 (42%)
|
Anticoagulant
|
Patients without IHD (N = 1218)
|
19 (1.6%)
|
0.001
|
Patients with IHD (N = 300)
|
18 (6%)
|
ARB and diuretic
|
Patients without IHD (N = 1218)
|
2 (0.2%)
|
0.042
|
Patients with IHD (N = 300)
|
3 (1%)
|
SSRI
|
Patients without IHD (N = 1218)
|
41 (3.4%)
|
0.310
|
Patients with IHD (N = 300)
|
8 (2.7%)
|
Anticonvulsant
|
Patients without IHD (N = 1218)
|
49 (4%)
|
0.017
|
Patients with IHD (N = 300)
|
26 (8.7%)
|
Antipsychotic
|
Patients without IHD (N = 1218)
|
29 (2.4%)
|
0.272
|
Patients with IHD (N = 300)
|
4 (1.3%)
|
Methylprednisolone
|
Patients without IHD (N = 1218)
|
688 (56.5%)
|
0.395
|
Patients with IHD (N = 300)
|
154 (51.3%)
|
Prednisolone
|
Patients without IHD (N = 1218)
|
55 (4.5%)
|
0.244
|
Patients with IHD (N = 300)
|
19 (6.3%)
|
Clinical presentations
The presenting symptoms of patients are summarized in Table 3. The five most common symptoms in the IHD group were cough (73.7%), fever (65%), shortness of breath (62.3%), weakness and fatigue (59.3%), and chills (50.7%), respectively. On the other hand, the five most common symptoms in the non-IHD group were fever (75.7%), cough (71.8%), shortness of breath (61.6%), chills (60.1%), and weakness and fatigue (59.4%), respectively. Analyses showed patients with IHD were significantly less likely to present symptoms, including fever (OR: 0.57, 95% CI: 0.42–0.78, P < 0.001), chills (OR: 0.64, 95% CI: 0.47–0.86, P < 0.001) and diarrhea (OR: 0.66, 95% CI: 0.48–0.91, P = 0.010). The other symptoms had no significant difference between the two groups. The mean length of symptoms presentation was 7.74 ± 5.67 days in the IHD and 8.23 ± 6.12 days in the non-IHD group (P = 0.219).
Table 3
descriptive analysis of clinical variables with odds ratio and 95% CI
variable
|
Patients with IHD
(N = 300)
|
Patients without IHD (N = 1218)
|
P-value
|
Odds ratio
(95%CI)
|
Mean(SD)
|
N (%)
|
Mean(SD)
|
N (%)
|
Fever (Yes)
|
|
195(65%)
|
|
922(75.7%)
|
< 0.001
|
0.57
(0.42–0.78)
|
Chill (Yes)
|
|
152(50.7%)
|
|
732(60.1%)
|
< 0.001
|
0.64
(0.47–0.86)
|
Cough (Yes)
|
|
221(73.7%)
|
|
874(71.8%)
|
0.778
|
1.09
(0.79–1.5)
|
Sore throat (Yes)
|
|
46(15.3%)
|
|
205(16.8%)
|
0.727
|
0.94
(0.65–1.36)
|
Loss of smell (Yes)
|
|
33(11%)
|
|
162(13.3%)
|
0.324
|
0.81
(0.52–1.24)
|
Sneeze (Yes)
|
|
15(5%)
|
|
85(7%)
|
0.353
|
0.76
(0.43–1.36)
|
Runny nose (Yes)
|
|
21(7%)
|
|
124(10.2%)
|
0.184
|
0.72
(0.44–1.17)
|
Body pain (Yes)
|
|
151(50.3%)
|
|
689(56.6%)
|
0.071
|
0.75
(0.56–1.02)
|
Nausea (Yes)
|
|
95(31.7%)
|
|
439(36%)
|
0.083
|
0.78
(0.58–1.03)
|
Vomiting (Yes)
|
|
61(20.3%)
|
|
285(23.4%)
|
0.208
|
0.82
(0.59–1.12)
|
Diarrhea (Yes)
|
|
59(19.7%)
|
|
332(27.3%)
|
0.010
|
0.66
(0.48–0.91)
|
Short of breath (Yes)
|
|
187(62.3%)
|
|
750(61.6%)
|
0.702
|
1.06
(0.79–1.43)
|
Decreased appetite (Yes)
|
|
143(47.7%)
|
|
535(43.9%)
|
0.181
|
1.28
(0.89–1.85)
|
Abdominal Pain (Yes)
|
|
46(15.3%)
|
|
190(15.6%)
|
0.999
|
1
(0.69–1.45)
|
Headache (Yes)
|
|
84(28%)
|
|
413(33.9%)
|
0.055
|
0.74
(0.54–1.01)
|
Chest Pain (Yes)
|
|
64(21.3%)
|
|
299(24.5%)
|
0.294
|
0.84
(0.6–1.16)
|
Weakness Fatigue (Yes)
|
|
178(59.3%)
|
|
724(59.4%)
|
0.983
|
1
(0.7–1.43)
|
Weight Loss (Yes)
|
|
45(15%)
|
|
215(17.7%)
|
0.230
|
0.79
(0.54–1.16)
|
Nasal Congestion (Yes)
|
|
8(2.7%)
|
|
48(3.9%)
|
0.333
|
0.68
(0.32–1.48)
|
Symptom duration
|
7.74 (5.67)
|
|
8.23 (6.12)
|
|
0.219
|
-
|
Vital symptoms
|
Systolic blood pressure (mmHg)
|
131.58 (57.46)
|
|
132 (22.03)
|
|
0.038
|
-
|
Systolic blood pressure (≥ 140)
|
|
86(28.6%)
|
|
282(23.2%)
|
0.046
|
1.33
(1.0-1.77)
|
Systolic blood pressure (< 90)
|
|
3(1%)
|
|
13(1.1%)
|
0.919
|
0.93
(0.26–3.30)
|
Diastolic blood pressure (mmHg)
|
79.1 (13.97)
|
|
80.11 (35.15)
|
|
0.435
|
-
|
Diastolic blood pressure (≥ 90)
|
|
49(16.3%)
|
|
151(12.4%)
|
0.071
|
1.37
(0.97–1.96
)
|
Heart rate on admission (beat/min)
|
90.02 (17.33)
|
|
93
(15.72)
|
|
0.007
|
-
|
Heart rate on admission ( > = 100)
|
|
82(27.3%)
|
|
402(33%)
|
0.059
|
0.76
(0.58–1.01)
|
Respiratory rate on admission (breath/min)
|
22.96 (6.04)
|
|
22.42 (6.34)
|
|
0.180
|
-
|
Respiratory rate on admission ( > = 20)
|
|
208(69.3%)
|
|
831(68.2%)
|
0.712
|
1.05
(0.8–1.38)
|
Temperature on admission (℃)
|
37.42 (2.21)
|
|
37.52 (0.99)
|
|
0.406
|
-
|
Temperature on admission ( > = 38)
|
|
107(35.7%)
|
|
427(35.1%)
|
0.843
|
1.03
(0.79–1.34)
|
SaO2
|
85.1 (10.34)
|
|
87.85 (27.46)
|
|
0.005
|
|
SaO2 (< 93)
|
|
250(83.3%)
|
|
926(76.0%)
|
0.007
|
1.57
(1.13–2.19)
|
Vitals Sign
At the time of admission, body temperature (T) (37.42 ± 2.21 vs. 37.52 ± 0.99°C, P = 0.406), diastolic blood pressure (79.1 ± 13.97 vs. 80.11 ± 35.15 mmHg, P = 0.435), tachypnea (69.3% vs. 68.2%, P = 0.712) and tachycardia (27.3% vs. 33%, P = 0.059) were not statistically significant different between IHD and non-IHD groups. The hypertension was significantly higher in the IHD group (OR: 1.33, 95%CI: 1.0-1.77, P = 0.046). However, the frequency of hypotension (SBP < 90mmHg) and DBP ≥ 90 mmHg was not significantly different between groups. The mean oxygen saturation (85.1 ± 10.34% vs. 87.85 ± 27.46%, P = 0.005) and the mean HR (90.02 ± 17.33 vs. 93 ± 15.72 bit/min, P = 0.007) were significantly lower in IHD group. Patients with IHD were 1.57 times more likely to have hypoxemia (83.3% vs. 76%, OR: 1.57, 95% CI: 1.13–2.19, P = 0.007) (Table 3).
Laboratory Finding
Quantitative and qualitative comparison of laboratory data showed that white blood cell counts, platelets, lymphocytes, lactate dehydrogenase (LDH), aspartate transaminase (AST), and C-reactive protein (CRP) were not significantly different between the two groups. Though the alanine transaminase (ALT) level was significantly higher in the IHD group (37.24 ± 40.2 U/L vs. 32.7 ± 27.62 U/L, P = 0.023), there was no significant difference in the frequency of abnormal levels of ALT between the two groups (42% vs. 40.6%, P = 0.667). (Table 4).
Table 4
Descriptive analysis of laboratory variables
Variables
|
IHD history of patients
|
Mean(SD)
|
N (%)
|
P-value
|
Plt
|
Patients without IHD(N = 1218)
|
192.84 (76.34)
|
|
0.848
|
Patients with IHD (N = 300)
|
191.61 (77.86)
|
|
Plt (< 150)
|
Patients without IHD(N = 1218)
|
|
356 (29.2%)
|
0.804
|
Patients without IHD (N = 300)
|
|
86 (28.7%)
|
White blood cell count ( × 10 9 /L)
|
Patients without IHD (N = 1218)
|
6225.22 (8618.48)
|
|
0.987
|
Patients with IHD (N = 300)
|
6233.31 (3301.1)
|
|
White blood cell count (< 400 OR > 11000 )
|
Patients without IHD (N = 1218)
|
|
373 (30.6%)
|
0.219
|
Patients with IHD (N = 300)
|
|
81 (27%)
|
Lymphocyte (µL)
|
Patients without IHD (N = 1218)
|
1199.2 (4620.94)
|
|
0.645
|
Patients with IHD (N = 300)
|
1075.4 (686.43)
|
|
Lymphocyte (< 1100)
|
Patients without IHD (N = 1218)
|
|
743 (61.0%)
|
0.541
|
Patients with IHD (N = 300)
|
|
175 (58.3%)
|
LDH (U/L)
|
Patients without IHD (N = 1218)
|
690.43 (586.59)
|
|
0.770
|
Patients with IHD (N = 300)
|
675.59 (457)
|
|
LDH (> 250 U/L)
|
Patients without IHD (N = 1218)
|
|
566 (46.5%)
|
0.159
|
Patients with IHD (N = 300)
|
|
153 (51.0%)
|
AST(U/L)
|
Patients without IHD (N = 1218)
|
46.85 (39.07)
|
|
0.593
|
Patients with IHD (N = 300)
|
45.53 (32.84)
|
|
AST(> 40 U/L)
|
Patients without IHD (N = 1218)
|
|
512 (42.0%)
|
0.667
|
Patients with IHD (N = 300)
|
|
122 (40.6%)
|
ALT(U/L)
|
Patients without IHD (N = 1218)
|
37.24 (40.2)
|
|
0.023
|
Patients with IHD (N = 300)
|
32.7 (27.62)
|
|
ALT(> 50 U/L)
|
Patients without IHD (N = 1218)
|
|
224 (18.4%)
|
0.130
|
Patients with IHD (N = 300)
|
|
44 (14.6%)
|
CRP0
|
Patients without IHD (N = 1218)
|
58.21 (53.42)
|
|
0.646
|
Patients with IHD (N = 300)
|
56.45 (53.45)
|
|
CRP0(100)
|
Patients without IHD (N = 1218)
|
|
176 (14.4%)
|
0.427
|
Patients with IHD (N = 300)
|
|
38 (12.7%)
|
CRP0(10)
|
Patients without IHD (N = 1218)
|
|
804 (66%)
|
0.079
|
Patients with IHD (N = 300)
|
|
214 (71.3%)
|
Clinical Outcomes
Length of hospitalization was significantly higher in the IHD group (8.4 ± 5.57 days vs.7.5 ± 5.5 days, P = 0.027). However, the frequency of ICU admission, length of ICU admission, the frequency of mechanical ventilation, length of mechanical ventilation, death and time from admission to death were not significantly different between the IHD and non-IHD groups (Table 5).
Table 5
Outcomes
|
IHD history of patients
|
N
(%)
|
Mean
(SD)
|
p-value
|
ICU admission
|
Patients without IHD (N = 1218)
|
181 (14.9%)
|
|
0.726
|
Patients with IHD (N = 300)
|
47 (15.7%)
|
|
Duration of ICU admission
|
Patients without IHD (N = 1218)
|
|
8.96 (7.21)
|
0.673
|
Patients with IHD (N = 300)
|
|
9.45 (6.16)
|
mechanical ventilation
|
Patients without IHD (N = 1218)
|
61 (5%)
|
|
0.818
|
Patients with IHD (N = 300)
|
16 (5.3%)
|
|
Duration of mechanical ventilation
|
Patients without IHD (N = 1218)
|
|
8.81 (8.05)
|
0.853
|
Patients with IHD (N = 300)
|
|
8.44 (6.82)
|
Death status
|
Patients without IHD (N = 1218)
|
92 (7.6%)
|
|
0.163
|
Patients with IHD (N = 300)
|
30 (10%)
|
|
Time to death
|
Patients without IHD (N = 1218)
|
|
13.1 (9.41)
|
0.392
|
Patients with IHD (N = 300)
|
|
11.32 (7.78)
|
Duration of hospitalization
|
Patients without IHD (N = 1218)
|
|
7.5 (5.5)
|
0.027
|
Patients with IHD (N = 300)
|
|
8.4 (5.7)
|
Moreover, adjusting for age, history of hypertension, CKD, ESRD and DM by Cox proportional hazards regression models and unstandardized confidants by linear regression models showed no significant difference between the two groups regarding the frequency of ICU admission, length of ICU admission, the frequency of mechanical ventilation, length of mechanical ventilation, death and time from admission to death (Table 6).
Table 6
Estimated HRs and 95% CIs by Cox proportional hazards regression models and unstandardized confidents by linear regression models for different outcomes based on IHD groups
Outcomes
|
Adjusted COX
regression
|
Adjusted linear
regression
|
p-value
|
Hazard Ratio
|
95% CI
|
B
Coefficient
|
95% CI
|
ICU admission
|
1.3
|
(0.8 _ 1.8)
|
|
|
0.206
|
Duration of ICU admission
|
|
|
0.65
|
(-1.8 _ 3.1)
|
0.531
|
mechanical ventilation
|
1.2
|
(0.6 _ 2.2)
|
|
|
0.622
|
Duration of mechanical ventilation
|
|
|
0.07
|
-4.7 _ 4.8)
|
0.977
|
Time to death
|
|
|
-2.1
|
(-6.4 _ 2.1)
|
0.318
|
Death status
|
1.4
|
(0.9 _ 2.4)
|
|
|
0.159
|
Duration of hospitalization
|
|
|
0.32
|
(-0.4 _ 1.1)
|
0.404
|