Patient characteristics
The total number of included cases was 2,702 (that is 872, 921, and 909 selected cases from Taikang-Tongji, Huoshenshan, and Guanggu Woman and Child Hospitals, respectively). Table 1 shows the inpatients’ demographic characteristics.
They were all Chinese: 1,326 female and 1,376 male inpatients; 2,618 were natives of Hubei province, while 84 were not. The mean age was 55.52 ± 16.09 years and 54.18 ± 15.85 years for female and male populations, respectively. The mean age for the male population was significantly lower (P = 0.03). No significant difference was found in symptoms duration before hospitalization, length of stay, and overall duration of symptoms between female and male populations.
For age groups, there were significant difference in symptoms duration before hospitalization, length of stay, and overall duration of symptoms according to the ANOVA test (P > 0.05). The least significant difference (LSD) test showed that in symptoms duration before hospitalization, age group 20–29 years had the lowest duration, whereas the group 60–69 years had highest age duration, with a significant difference between the groups (P < 0.05).
Table 1
Demographic characteristics of inpatients
Characteristics
|
Number of patients
|
Proportion
|
Hospital
|
|
|
Taikang-Tongji
|
872
|
32.27%
|
Huoshenshan
|
921
|
34.09%
|
Guanggu Woman and Child
|
909
|
33.64%
|
Gender
|
|
|
Female
|
1326
|
49.07%
|
Male
|
1376
|
50.93%
|
Native place
|
|
|
Hubei province
|
2618
|
96.89%
|
Outside Hubei province
|
84
|
3.11%
|
Duration Of Symptoms
Table 2 shows the means for the inpatients age, BMI, symptoms duration before hospitalization, length of stay, and overall duration of symptoms by hospital, gender, and age group. There were no significant differences in age, symptoms duration before hospitalization, length of stay, and overall duration of symptoms among the three hospitals according to the ANOVA test (P > 0.05). The inpatients’ age ranged from 11 to 94 years, with a mean of 54.84 ± 15.98 years, while BMI ranged from 16.23 to 28.7, with a mean of 22.11 ± 1.94. The length of stay ranged from 5 to 50 days, with a mean of 17.88 ± 7.38 days; the self-reported symptom duration before hospitalization ranged from 2 to 72 days, with a mean of 24.11 ± 15.66 days. By combining the duration of inpatient and self-reported symptom duration before hospitalization, we obtained the duration of the symptoms, which ranged from 7 to 94 days, with a mean of 41.99 ± 16.37 days.
Table 2
Means of age, body mass index, symptoms duration before hospitalization, length of stay, and overall duration of symptoms by hospital, gender, and age group of the inpatients
|
Age
|
Body mass index
|
Symptoms duration before hospitalization
|
Length of stay
|
Overall duration of symptoms
|
Hospital
|
|
|
|
|
|
Taikang-Tongji (n = 872)
|
54.76 ± 15.75
|
22.25 ± 1.92
|
24.36 ± 15.92
|
17.92 ± 7.42
|
42.28 ± 16.57
|
Huoshenshan (n = 921)
|
55.21 ± 15.88
|
22.02 ± 2.00
|
24.65 ± 15.65
|
17.91 ± 7.34
|
42.55 ± 16.33
|
Guanggu Woman and Child (n = 909)
|
54.53 ± 16.29
|
22.07 ± 1.90
|
23.34 ± 15.40
|
17.80 ± 7.39
|
41.15 ± 16.21
|
Gender
|
|
|
|
|
|
Female (n = 1326)
|
55.52 ± 16.09
|
22.14 ± 1.92
|
24.11 ± 15.40
|
18.11 ± 7.34
|
42.22 ± 16.04
|
Male (n = 1376)
|
54.18 ± 15.85
|
22.08 ± 1.96
|
24.12 ± 15.92
|
17.66 ± 7.41
|
41.77 ± 16.69
|
Age group (years)
|
|
|
|
|
|
< 20 (n = 49)
|
15.59 ± 2.53
|
21.79 ± 2.19
|
24.61 ± 14.01
|
13.22 ± 5.67
|
37.84 ± 13.16
|
20–29 (n = 116)
|
25.35 ± 2.53
|
21.95 ± 1.76
|
16.28 ± 12.36
|
14.91 ± 5.69
|
31.20 ± 14.32
|
30–39 (n = 305)
|
34.87 ± 2.84
|
22.21 ± 1.98
|
23.77 ± 16.68
|
15.79 ± 6.71
|
39.56 ± 17.44
|
40–49 (n = 529)
|
44.84 ± 2.96
|
22.10 ± 1.97
|
21.56 ± 14.29
|
17.24 ± 6.93
|
38.80 ± 14.31
|
50–59 (n = 592)
|
54.68 ± 2.80
|
22.13 ± 1.97
|
23.83 ± 15.81
|
17.98 ± 7.20
|
41.81 ± 16.15
|
60–69 (n = 635)
|
64.16 ± 2.72
|
22.2 ± 1.910
|
27.63 ± 16.08
|
18.49 ± 7.12
|
46.12 ± 16.39
|
70–79 (n = 306)
|
73.96 ± 2.88
|
21.99 ± 1.84
|
25.12 ± 15.95
|
20.34 ± 8.09
|
45.46 ± 16.04
|
> 79 (n = 170)
|
84.49 ± 3.35
|
21.97 ± 2.04
|
23.94 ± 14.37
|
19.86 ± 8.96
|
43.79 ± 17.55
|
Overall (n = 2702)
|
54.84 ± 15.98
|
22.11 ± 1.94
|
24.11 ± 15.66
|
17.88 ± 7.38
|
41.99 ± 16.37
|
To further analyze the course of the disease (duration of symptom before hospitalization, length of stay, and overall duration of symptom), we drew line diagrams of the means by age group and gender (Figs. 3 to 5). We also performed two-way ANOVA to test for the difference in the mean course of disease by age group and gender. The results showed that age was significantly associated with the three course of disease variables (P < 0.05), whereas gender was not associated, and two factors had no significant interaction effect (P > 0.05).
We also calculated each symptom’s cumulative duration (in days) by three levels of severity in the overall sample population (Table 3). Fever and fatigue had the longest duration, with a cumulative duration of 26,863 days. The lowest cumulative duration occurred with anxiety and depression, which had 4,565 days. By chi-square test, the proportion of severity differed significantly among different symptoms (P < 0.05). Anxiety and depression had the highest proportion of severe conditions (30.54%), whereas cough and sore throat had the highest proportion of mild conditions (10.63%). Based on these findings, composition proportions of the cumulative duration (in days) by symptom in the whole study population are shown in Fig. 6a. Cough and sore throat contributed the largest part of the symptom duration, with a proportion of 32.06%, whereas anxiety and depression contributed the least, with a proportion of 3.72%.
Table 3
Disability weights for the symptoms of COVID-19
Category
|
Symptom categories
|
Health stages
|
DWs
|
95% CI
|
Systemic symptoms
|
Fever and fatigue
|
Mild
Moderate
Severe
|
0.006
0.051
0.133
|
(0.004–0.008)
(0.036–0.066)
(0.089–0.177)
|
|
Muscular soreness
|
Mild
Moderate
Severe
|
0.015
0.054
0.110
|
(0.012–0.018)
(0.041–0.067)
(0.059–0.113)
|
Neurological symptoms
|
Dizziness and headache
|
Mild
Moderate
Severe
|
0.028
0.083
0.163
|
(0.019–0.037)
(0.055–0.111)
(0.109–0.217)
|
Respiratory symptoms
|
Expiratory dyspnea
|
Mild
Moderate
Severe
|
0.045
0.108
0.399
|
(0.040–0.050)
(0.085–0.131)
(0.293–0.505)
|
|
Cough and sore throat
|
Mild
Moderate
Severe
|
0.004
0.011
0.034
|
(0.003–0.005)
(0.008–0.014)
(0.023–0.045)
|
Cardiovascular symptoms
|
Palpitations and chest tightness
|
Mild
Moderate
Severe
|
0.041
0.072
0.179
|
(0.029–0.053)
(0.048–0.096)
(0.120–0.238)
|
Gastrointestinal symptoms
|
Nausea and vomiting
|
Mild
Moderate
Severe
|
0.009
0.057
0.130
|
(0.006–0.012)
(0.038–0.076)
(0.089–0.171)
|
|
Abdominal pain and diarrhea
|
Mild
Moderate
Severe
|
0.011
0.091
0.194
|
(0.008–0.014)
(0.062–0.120)
(0.128–0.260)
|
Psychological symptoms
|
Anxiety and depression
|
Mild
Moderate
Severe
|
0.030
0.120
0.366
|
(0.021–0.039)
(0.084–0.156)
(0.243–0.489)
|
COVID-19, coronavirus disease 2019; DWs, disability weights; CI, confidence interval |
Table 3
Each COVID-19 symptom’s cumulative duration (in days) in the study population
Symptoms
|
Mild
|
Moderate
|
Severe
|
Overall duration
(days)
|
Day
|
%
|
Day
|
%
|
Day
|
%
|
Fever and fatigue
|
2,231
|
8.31
|
20,846
|
77.60
|
3,785
|
14.09
|
26,863
|
Muscular soreness
|
334
|
3.08
|
8,220
|
75.71
|
2,303
|
21.21
|
10,858
|
Dizziness and headache
|
92
|
1.68
|
3,864
|
70.51
|
1,524
|
27.81
|
5,481
|
Expiratory dyspnea
|
104
|
1.83
|
4,096
|
72.23
|
1,471
|
25.94
|
5,672
|
Cough and sore throat
|
4,180
|
10.63
|
30,172
|
76.75
|
4,959
|
12.61
|
39,312
|
Palpitations and chest tightness
|
862
|
5.86
|
11,232
|
76.34
|
2,620
|
17.81
|
14,715
|
Nausea and vomiting
|
387
|
4.40
|
6,434
|
73.19
|
1,970
|
22.41
|
8,792
|
Abdominal pain and diarrhea
|
150
|
2.36
|
4,534
|
71.30
|
1,675
|
26.34
|
6,360
|
Anxiety and depression
|
35
|
0.77
|
3,135
|
68.69
|
1,394
|
30.54
|
4,565
|
Overall
|
8,375
|
6.83
|
92,533
|
75.47
|
21,701
|
17.70
|
122,610
|
COVID-19, coronavirus disease 2019. |
Dws Of Covid-19 Symptoms
After two rounds of the Delphi process by the panel, we developed a 9-item COVID-19 symptoms’ list with six categories. Each symptom included three levels of severity (mild, moderate, and severe), thereby representing 27 health stages. Based on these, we derived the DWs for each health stage by the PTO exercise; along with the expert panel, a consensus was reached at the fifth round of the Delphi process (CV < 0.5). Thus, the DWs of 27 COVID-19 health stages were derived; severe expiratory dyspnea had the highest weight of 0.399, while mild cough and sore throat had the lowest weight of 0.004, as shown in Table 3.
Daly Of Inpatients
According to the formula and DWs, the DALY of each inpatient for each symptom was calculated, as well as their synthetic DALY and DALY per day. The composition proportion of DALY in the study population is shown in Fig. 6b. Among these, fever and fatigue contributed the largest part of the DALY, with a proportion of 31.36%, whereas nausea and vomiting and anxiety and depression contributed the smallest part, at 7.05%.
The mean and standard deviation of DALY by symptom by hospital, gender, and overall study population are shown in Table 4, and those by age group are shown in Table 5. The mean overall DALY in the overall study population was 2.29 ± 1.33 days, whereas the mean DALY per day was 0.18 ± 0.15 days. Among the three hospitals, no significant difference occurred with each symptom’s DALY, the synthetic DALY, or the DALY per day in ANOVA test (P > 0.05). However, in the LSD test of the ANOVA, synthetic DALY in Huoshenshan Hospital was significantly lower than that in Taikang-Tongji (P = 0.048) and Guanggu Woman and Child (P = 0.031) Hospitals, respectively. The DALY per day in Huoshenshan Hospital was significantly lower than that in Guanggu Woman and Child Hospital (P = 0.023). The DALY for fever and fatigue, muscular soreness, palpitations and chest tightness, nausea and vomiting, and synthetic DALY was significantly lower for the male population than for the female population by t-test (P > 0.05). In the inpatient population the overall DALY per 1,000 capita was 6.28, in female and male population the overall DALY per 1,000 capita was 6.07 and 6.51 years respectively.
Table 4
The mean DALY of COVID-19 inpatient by symptoms in each hospital, gender, and overall study population
Symptom
|
Taikang-Tongji
(n = 872)
|
Huoshenshan
(n = 921)
|
Guanggu Woman and Child (n = 909)
|
Female (n = 1326)
|
Male (n = 1376)
|
Overall
(n = 2702)
|
Fever and fatigue
|
0.72 ± 0.60
|
0.70 ± 0.59
|
0.73 ± 0.63
|
0.75 ± 0.61
|
0.69 ± 0.60‡
|
0.72 ± 0.61
|
Muscular soreness
|
0.19 ± 0.18
|
0.18 ± 0.17
|
0.18 ± 0.17
|
0.19 ± 0.18
|
0.18 ± 0.17‡
|
0.18 ± 0.17
|
Dizziness and headache
|
0.14 ± 0.18
|
0.13 ± 0.17
|
0.14 ± 0.20
|
0.13 ± 0.17
|
0.14 ± 0.19
|
0.14 ± 0.18
|
Expiratory dyspnea
|
0.18 ± 0.31
|
0.18 ± 0.32
|
0.21 ± 0.38
|
0.19 ± 0.34
|
0.19 ± 0.33
|
0.19 ± 0.34
|
Cough and sore throat
|
0.18 ± 0.12
|
0.18 ± 0.12
|
0.18 ± 0.13
|
0.18 ± 0.12
|
0.18 ± 0.13
|
0.18 ± 0.12
|
Palpitations and chest tightness
|
0.41 ± 0.45
|
0.37 ± 0.40
|
0.39 ± 0.43
|
0.42 ± 0.44
|
0.36 ± 0.41‡
|
0.39 ± 0.43
|
Nausea and vomiting
|
0.16 ± 0.24
|
0.16 ± 0.23
|
0.17 ± 0.24
|
0.17 ± 0.25
|
0.15 ± 0.23‡
|
0.16 ± 0.24
|
Abdominal pain and diarrhea
|
0.18 ± 0.30
|
0.16 ± 0.26
|
0.17 ± 0.24
|
0.17 ± 0.26
|
0.16 ± 0.28
|
0.17 ± 0.27
|
Anxiety and depression
|
0.16 ± 0.23
|
0.15 ± 0.21
|
0.17 ± 0.24
|
0.16 ± 0.23
|
0.17 ± 0.23
|
0.16 ± 0.23
|
Total DALY
|
2.33 ± 1.33
|
2.21 ± 1.26*
|
2.34 ± 1.38
|
2.38 ± 1.33
|
2.21 ± 1.32‡
|
2.29 ± 1.33
|
DALY per day
|
0.19 ± 0.14
|
0.18 ± 0.14*†
|
0.19 ± 0.16
|
0.19 ± 0.14
|
0.18 ± 0.15
|
0.18 ± 0.15
|
* P < 0.05 vs. Guanggu Woman and Child Hospital; † P < 0.05 vs. Taikang-Tongji Hospital; ‡ P < 0.05 vs. female. |
DALY, Disability-adjusted life years.
Table 5
COVID-19 inpatient DALY by symptoms and age group
Symptom
|
< 20 years
(n = 49)
|
20–29 years
(n = 116)
|
30–39 years
(n = 305)
|
40–49 years
(n = 529)
|
50–59 years
(n = 592)
|
60–69 years
(n = 635)
|
70–79 years
(n = 306)
|
> 79 years
(n = 170)
|
Fever and fatigue
|
0.75 ± 0.58
|
0.79 ± 0.73
|
0.99 ± 0.89
|
0.88 ± 0.70
|
0.73 ± 0.54
|
0.60 ± 0.42
|
0.55 ± 0.38
|
0.39 ± 0.28
|
Muscular soreness
|
0.14 ± 0.12
|
0.16 ± 0.19
|
0.25 ± 0.23
|
0.22 ± 0.20
|
0.19 ± 0.16
|
0.16 ± 0.13
|
0.15 ± 0.12
|
0.11 ± 0.09
|
Dizziness and headache
|
0.15 ± 0.18
|
0.13 ± 0.16
|
0.17 ± 0.22
|
0.16 ± 0.22
|
0.16 ± 0.21
|
0.11 ± 0.13
|
0.10 ± 0.11
|
0.08 ± 0.09
|
Expiratory dyspnea
|
0.19 ± 0.24
|
0.11 ± 0.15
|
0.18 ± 0.28
|
0.21 ± 0.43
|
0.25 ± 0.45
|
0.17 ± 0.24
|
0.13 ± 0.19
|
0.18 ± 0.25
|
Cough and sore throat
|
0.20 ± 0.09
|
0.25 ± 0.13
|
0.26 ± 0.15
|
0.21 ± 0.14
|
0.18 ± 0.12
|
0.15 ± 0.09
|
0.14 ± 0.08
|
0.09 ± 0.06
|
Palpitations and chest tightness
|
0.33 ± 0.43
|
0.54 ± 0.54
|
0.51 ± 0.61
|
0.47 ± 0.5
|
0.37 ± 0.35
|
0.37 ± 0.34
|
0.31 ± 0.33
|
0.17 ± 0.17
|
Nausea and vomiting
|
0.21 ± 0.28
|
0.25 ± 0.36
|
0.21 ± 0.30
|
0.17 ± 0.23
|
0.18 ± 0.25
|
0.15 ± 0.22
|
0.10 ± 0.12
|
0.06 ± 0.07
|
Abdominal pain and diarrhea
|
0.10 ± 0.11
|
0.25 ± 0.31
|
0.22 ± 0.43
|
0.22 ± 0.36
|
0.15 ± 0.20
|
0.13 ± 0.17
|
0.13 ± 0.17
|
0.10 ± 0.16
|
Anxiety and depression
|
0.21 ± 0.25
|
0.18 ± 0.24
|
0.21 ± 0.28
|
0.20 ± 0.28
|
0.19 ± 0.25
|
0.14 ± 0.16
|
0.09 ± 0.12
|
0.06 ± 0.08
|
Synthetic DALY
|
2.28 ± 0.93
|
2.65 ± 1.46
|
2.98 ± 1.87
|
2.74 ± 1.52
|
2.41 ± 1.12
|
1.98 ± 0.92
|
1.70 ± 0.79
|
1.24 ± 0.69
|
DALY per day
|
0.21 ± 0.11
|
0.21 ± 0.15
|
0.25 ± 0.18
|
0.22 ± 0.17
|
0.20 ± 0.16
|
0.15 ± 0.10
|
0.11 ± 0.06
|
0.09 ± 0.06
|
COVID-19, coronavirus disease 2019. |
DALY, Disability-adjusted life years.
According to the ANOVA test, the mean DALY by age groups differed significantly for each symptom and also for the synthetic DALY and DALY per day (P < 0.05). The DALY for both single symptoms and synthesized DALY had the tendency of an inverse U-shaped curve. The DALY increased with age, reached a peak in the prime of life, and then slowly decreased with age. In this study, the 40–49 years age group had the highest DALY for expiratory dyspnea; while the 20–29 years group had the highest DALY for palpitations and chest tightness, nausea and vomiting, and abdominal pain and diarrhea. DALY for the other symptoms, synthetic DALY, and DALY per day peaked in those aged 20–29 years.
The composition of synthetic DALY for each symptom by hospital is shown in Fig. 7, and the composition of the synthetic DALY by gender and age group are shown in Fig. 8 and Fig. 9, respectively.
To visualize each symptom’s DALY by age group and gender, we drew a thermal map for each subgroup’s DALY per 1,000 capita (in days), as shown in Fig. 10. Fever and fatigue were in the most intense (red) area, while palpitations and chest tightness were the next intense area, for both female and male populations. Female population aged 30–39 years had the highest DALY score of 1,115 DALY (in days) per 1,000 capita. On the contrary, in the female population above 79 years, the lowest DALY temperature of 50 DALY (in days) per 1,000 capita was found.
We also identified the changing curves of the means synthetic DALY, DALY per day and by age groups and gender, as shown in Fig. 11 and Fig. 12. The two-way ANOVA test showed that both age and gender significantly affected synthetic DALY (P < 0.05); and there was a significant interaction effect between the two variables (P = 0.02). However, when DALY per day was the dependent variable, the significant difference with gender was lost (P = 0.08), whereas age remained significant (P < 0.05), and the interaction effect between the two variables was also lost (P = 0.518).
Linear Regression Analyses
The results of the multiple linear models are shown in Table 6. When synthetic DALY was set as the dependent variable, all of the four models were significant (P < 0.05), with R2 ranging from 0.214 to 0.240. In the four models, symptom duration before hospitalization and length of stay were significantly positively associated with synthetic DALY; while age was significantly negatively associated with the overall synthetic DALY. For gender and BMI, however, the four models showed different results. In the Guanggu Woman and Child Hospital model, gender and BMI were not significant (P = 0.098 and P = 0.146); in contrast, in the other three models, gender and BMI were significant, indicating that the female population had higher DALY than the male population (P < 0.05), and high BMI population had higher DALY (P < 0.05).
When DALY per day was set as the dependent variable, all of the four models were significant (P < 0.05), with R2 ranging from 0.153 to 0.188. For age and symptom duration before hospitalization, the level of significance was the same as with model type I. Length of stay remained significant; however, the effectiveness was negatively reversed for DALY. For gender, the overall sample and Huoshenshan Hospital models were significant (P = 0.037 and P = 0.022, respectively), and for BMI, the overall sample and Taikang-Tongji Hospital models were significant (P < 0.001 and P = 0.001, respectively). In all the models, native place was not significant (P > 0.05).
Table 6
Linear regression analyses between COVID-19 inpatient’s DALY and individual variables
Variable
|
Model Type I *
|
Model Type II **
|
Overall sample
|
Taikang-Tongji
|
Huoshenshan
|
Guanggu Woman and Child
|
Overall sample
|
Taikang-Tongji
|
Huoshenshan
|
Guanggu Woman and Child
|
R2 = 0.222
|
R2 = 0.214
|
R2 = 0.224
|
R2 = 0.240
|
R2 = 0.164
|
R2 = 0.188
|
R2 = 0.170
|
R2 = 0.153
|
β
|
P-value
|
β
|
P-value
|
β
|
P-value
|
β
|
P-value
|
β
|
P-value
|
β
|
P-value
|
β
|
P-value
|
β
|
P-value
|
Age
|
-0.415
|
< 0.001
|
-0.431
|
< 0.001
|
-0.388
|
< 0.001
|
-0.429
|
< 0.001
|
-0.290
|
< 0.001
|
-0.288
|
< 0.001
|
-0.269
|
< 0.001
|
-0.312
|
< 0.001
|
Gender
|
0.069
|
< 0.001
|
0.070
|
0.020
|
0.088
|
0.003
|
0.048
|
0.098
|
0.037
|
0.037
|
0.047
|
0.123
|
0.070
|
0.022
|
-0.002
|
0.956
|
Symptom duration before hospitalization
|
0.166
|
< 0.001
|
0.169
|
< 0.001
|
0.206
|
< 0.001
|
0.133
|
< 0.001
|
0.208
|
< 0.001
|
0.207
|
< 0.001
|
0.251
|
< 0.001
|
0.180
|
< 0.001
|
Length of stay
|
0.312
|
< 0.001
|
0.265
|
< 0.001
|
0.334
|
< 0.001
|
0.338
|
< 0.001
|
-0.139
|
< 0.001
|
-0.184
|
< 0.001
|
-0.134
|
< 0.001
|
-0.108
|
0.001
|
Body mass index
|
0.048
|
0.005
|
0.090
|
0.003
|
0.011
|
0.719
|
0.042
|
0.146
|
0.062
|
< 0.001
|
0.101
|
0.001
|
0.030
|
0.331
|
0.056
|
0.068
|
Native place
|
0.015
|
0.365
|
0.000
|
0.987
|
-0.017
|
0.549
|
0.030
|
0.303
|
0.003
|
0.856
|
-0.005
|
0.882
|
-0.002
|
0.951
|
0.024
|
0.437
|
COVID-19, coronavirus disease 2019; DALY, disability-adjusted life years. |
* Dependent variable is overall DALY;** Dependent variable is DALY per day. |