Based on our rigorous respondent choosing criteria and the on-duty status of participating doctors in this research. A total of 619 (37.6%) out of 1648 community deaths were included in this study. Of the 619 deaths for which a SmartVA interview was conducted, 570 also had available medical records for further MRR.
There was no significant difference in the age and sex composition between the 570 deaths and the total number of CHC deaths in same area and time period (Table 1) (p=0.862 for sex) (p=0.135 for age). The majority of deaths were in the 70 years and above age-group.
Table 1 Age-sex distribution of home deaths and deaths investigated by SmartVA in the 16 CHCs
Age
|
Total deaths reported by CHCs
|
Smart VA completed
|
Male(%)
|
Female(%)
|
Total
|
Male(%)
|
Female(%)
|
Total
|
N
|
%
|
N
|
%
|
<49
|
4.2
|
1.3
|
46
|
2.8
|
2.1
|
2.1
|
12
|
2.1
|
50-69
|
20.5
|
10.1
|
253
|
15.3
|
23.9
|
13.3
|
106
|
18.6
|
70~
|
75.3
|
88.5
|
1349
|
81.9
|
73.9
|
84.6
|
452
|
79.3
|
Total (%)
|
50.4
|
49.6
|
49.8
|
50.2
|
Total (N)
|
830
|
818
|
1648
|
284
|
286
|
570
|
For all home deaths in the 16 selected areas in 2017, the causes of death were classified into causes from the Smart VA cause list (see from Additional File 1). The cause specific mortality fractions (CSMF) for all the home deaths in the 16 CHCs in 2017 and the CSMFs for the collected VA results from this study, conducted in the same 16 regions in 2018, showed a similar COD distribution (see Table 2).
From the MRR of the deaths analysed by SmartVA for Physicians, stroke was the leading cause of death, accounting for 17.8% of deaths, followed by other cancers (15.6%) and ischaemic heart disease, lung cancer and chronic respiratory diseases, accounting for 12.6%, 12.1% and 11.2% of deaths, respectively. All other causes accounted for less than 5% of the CODs. Broadly speaking, causes of death diagnosed by SmartVA were similar to those before implementation, with only slight changes in the ranking of causes of death (Table 2).
Table 2 CSMFs of home deaths in the 16 regions of Shanghai in 2017 and in 2018
Rank
|
Home deaths in 2017 (before VA)
|
Home deaths in 2018 (Smart VA)
|
Leading cause of death
|
(%)
|
Leading cause of death
|
(%)
|
1
|
Stroke
|
19.2
|
Stroke
|
17.8
|
2
|
Ischaemic Heart Diseases
|
15.2
|
Other Cancers
|
15.6
|
3
|
Chronic Respiratory diseases
|
12.3
|
Ischaemic Heart Diseases
|
12.6
|
4
|
Other Cancers
|
11.7
|
Lung Cancer
|
12.1
|
5
|
Lung Cancer
|
7.8
|
Chronic Respiratory diseases
|
11.2
|
6
|
Other Non-communicable Diseases
|
6.4
|
Stomach Cancer
|
4.9
|
7
|
Diabetes
|
4.3
|
Other Non-communicable Diseases
|
4.5
|
8
|
Undetermined
|
4.2
|
Colorectal Cancer
|
3.3
|
9
|
Stomach Cancer
|
3.6
|
Other Cardiovascular Diseases
|
3.0
|
10
|
Colorectal Cancer
|
2.7
|
Falls
|
2.8
|
11
|
Falls
|
2.7
|
Diabetes
|
2.4
|
12
|
Other Cardiovascular Diseases
|
1.9
|
Esophageal Cancer
|
1.7
|
13
|
Esophageal Cancer
|
1.2
|
Leukemia/Lymphoma
|
1.7
|
14
|
Leukemia/Lymphoma
|
1.2
|
Other Infectious Diseases
|
1.4
|
15
|
Prostate Cancer
|
1.1
|
Other Injuries
|
1.4
|
The concordance between the initial diagnosis and MRR UCOD and post-VA diagnosis and MRR UCOD was assessed using Chance Corrected Concordance (CCC) (Table 3). This metric evaluates the average sensitivity weighted by the number of diseases, which makes the study comparable with other studies. CSMF accuracy was also evaluated by measuring the absolute deviation of the initial diagnosis CSMFs and the SmartVA CSFMs from MRR UCOD. The closer this value is to 1, the higher the concordance of the results[7, 11, 12].
The sensitivity and positive predictive value (PPV) were both high for the top six CODs. PPV was low for diabetes and other infectious diseases, which shows that a small number of original causes which were not diabetes or other infectious diseases were reallocated to other diseases after the VA investigation.
Although not dramatic, overall CSMF accuracy improved from 0.93, based on the initial diagnosis, to 0.96 after the application of SmartVA (see Table 3). As for specific causes, the CCCs for the top six causes of death (stroke, other cancers, IHD, lung cancer, CRD, and stomach cancer, accounting for over 75% of deaths) all increased to higher than 0.90 after VA-assisted diagnosis. Detailed metrics are shown in Tables 3-5. Some of the CODs have noticeable increases in CCC, especially other non-communicable diseases and other infectious diseases, after Smart VA. Of interest is the change in CCC of other cardiovascular diseases and falls; both decreased after the VA investigation. This may be because many deaths may initially, mistakenly be attributed to cardiovascular diseases, a COD that may not be supported after systematic and comprehensive investigations.
Table 3 Validation metrics comparing initial diagnosis or post-VA diagnosis with MRR UCOD (top 15 specific UCOD)
Rank
|
UCOD
|
Initial diagnosis
|
Post-VA diagnosis
|
Sensitivity
|
PPV
|
Kappa
|
CCC
|
CSMF
|
CSMF accuracy
|
Sensitivity
|
PPV
|
Kappa
|
CCC
|
CSMF
|
CSMF accuracy
|
1
|
Stroke
|
0.94
|
0.87
|
0.88
|
0.94
|
19.30
|
0.96
|
0.88
|
0.90
|
0.96
|
19.50
|
2
|
Other Cancers
|
0.88
|
0.96
|
0.90
|
0.87
|
14.20
|
0.94
|
0.93
|
0.93
|
0.94
|
15.80
|
3
|
Ischaemic Heart Diseases
|
0.89
|
0.85
|
0.85
|
0.88
|
13.20
|
0.93
|
0.89
|
0.90
|
0.93
|
13.20
|
4
|
Lung Cancer
|
0.97
|
0.99
|
0.98
|
0.97
|
11.90
|
0.97
|
1.00
|
0.98
|
0.97
|
11.80
|
5
|
Chronic Respiratory diseases
|
0.83
|
0.93
|
0.86
|
0.82
|
10.00
|
0.91
|
0.95
|
0.92
|
0.90
|
10.70
|
6
|
Stomach Cancer
|
0.96
|
0.90
|
0.93
|
0.96
|
5.30
|
1.00
|
0.93
|
0.96
|
1.00
|
5.30
|
7
|
Other Non-communicable Diseases
|
0.58
|
0.83
|
0.67
|
0.55
|
3.20
|
0.81
|
0.78
|
0.78
|
0.79
|
4.70
|
8
|
Colorectal Cancer
|
0.95
|
0.86
|
0.90
|
0.94
|
3.70
|
1.00
|
0.95
|
0.97
|
1.00
|
3.50
|
9
|
Other Cardiovascular Diseases
|
0.29
|
0.71
|
0.41
|
0.25
|
1.20
|
0.24
|
0.67
|
0.34
|
0.18
|
1.10
|
10
|
Falls
|
0.81
|
0.81
|
0.81
|
0.80
|
2.80
|
0.69
|
0.85
|
0.75
|
0.67
|
2.30
|
11
|
Diabetes
|
0.71
|
0.67
|
0.68
|
0.70
|
2.60
|
0.79
|
0.65
|
0.70
|
0.77
|
3.00
|
12
|
Leukemia/Lymphoma
|
0.90
|
0.90
|
0.90
|
0.89
|
1.80
|
1.00
|
0.91
|
0.95
|
1.00
|
1.90
|
13
|
Esophageal Cancer
|
0.90
|
0.90
|
0.90
|
0.89
|
1.80
|
0.90
|
1.00
|
0.95
|
0.89
|
1.60
|
14
|
Other Injuries
|
1.00
|
0.73
|
0.84
|
1.00
|
1.90
|
1.00
|
0.89
|
0.94
|
1.00
|
1.60
|
15
|
Other Infectious Diseases
|
0.38
|
0.60
|
0.46
|
0.33
|
0.90
|
0.75
|
0.86
|
0.80
|
0.73
|
1.20
|
16
|
Others
|
0.94
|
0.47
|
0.61
|
0.94
|
6.30
|
0.83
|
0.88
|
0.85
|
0.82
|
3.00
|
Total
|
0.80
|
0.93
|
0.85
|
0.96
|
Table 4 shows the misclassification matrix of the initial diagnosis compared to that from the MRR. The values in the yellow boxes are the CODs that were correctly classified after initial diagnosis; 86.3% (492/570) of the initial diagnoses assigned the correct CODs. Some of the misclassifications were adjusted after the VA investigation (Tables 4, 5), leading to correct classification of 90.5% (516/570) of the post-VA diagnosis.
From the results of the initial diagnosis before VA investigation, other cardiovascular diseases and other infectious diseases were more likely to be mis-assigned to other causes. Among these, nearly one third of other cardiovascular diseases were misclassified as stroke (6/17) (Table 4).
In the CSMFs after SmartVA, misclassification was reduced, except for the categories of other cardiovascular diseases and falls (Table 3). As before, other cardiovascular diseases were often misclassified as stroke, which accounted for 41% (7/17) of that diagnosis from MRR (Table 5).
Analysis of the VA results with SmartVA Auto analyse resulted in the causes of 53 deaths, or just under 10% of the sample, being reclassified from their initially assigned causes. This was particularly the case for chronic kidney diseases (CKD), chronic respiratory diseases, and cirrhosis, as well as falls, ischemic heart diseases (IHD), other CVD (Cardiovascular Diseases), and undetermined causes. Among these corrected CODs, CKD (5), cirrhosis (4) and IHD (3) were most often correctly classified after VA.
Among the 53 changed CODs, only 22.6% (12/53) of causes were assigned correctly before VA (Table 6), whereas 67.9% (36/53) of the new CODs were assigned correctly according to MRR (Table 7). The number of misclassified conditions, compared to MRR, were also reduced. In the 53 changed cases, all the causes assigned before VA (Table 6) had a high degree of misclassification, except for cirrhosis and falls. After VA, misclassification was greatly reduced, except for falls and other cardiovascular diseases (Table 7). Four undetermined deaths were reallocated to other diagnoses. (The concordance and validation metrics of comparing initial/VA diagnosis with MRR results can be seen from additional file 2 and 3).
For the 53 deaths with changed UCOD after SmartVA, the initially assigned CODs were distributed randomly between the 15 diseases/causes. In the initially assigned CODs, no cases were assigned to leukemia/lymphoma or other cancers, however, according to the MRR results other cancers should be the 3rd leading COD. Chronic kidney disease, undetermined, other injuries, pneumonia, cervical cancer and esophageal cancer were also not on the MRR disease list, while the CHC doctors assigned them as UCODs after initial diagnosis. This suggests a need for greater care when assigning these diseases as UCODs (see Table 8 for details).
With the assistance of SmartVA, the majority of deaths were assigned to other NCD (20.8%), chronic respiratory diseases (17.0%), and other cancers (17.0%). Though a small degree of misclassification persisted, the post-VA diagnosis of the UCOD agreed more closely with the reference standard (MRR) than the initial diagnosis (see Table 8).
Table 8 The distribution of UCOD for 53 changed causes
Changed cause
|
Initial(%)
|
Post-VA(%)
|
MRR(%)
|
1
|
Cervical Cancer
|
1.9
|
0.0
|
0.0
|
2
|
Chronic Kidney Disease
|
9.4
|
0.0
|
0.0
|
3
|
Chronic Respiratory diseases
|
9.4
|
17.0
|
17.0
|
4
|
Cirrhosis
|
9.4
|
1.9
|
1.9
|
5
|
Colorectal Cancer
|
3.8
|
1.9
|
1.9
|
6
|
Esophageal Cancer
|
1.9
|
0.0
|
0.0
|
7
|
Falls
|
7.5
|
1.9
|
7.5
|
8
|
Ischaemic Heart Diseases
|
7.5
|
7.5
|
11.3
|
9
|
Lung Cancer
|
3.8
|
1.9
|
3.8
|
10
|
Other Cardiovascular Diseases
|
7.5
|
5.7
|
7.5
|
11
|
Other Infectious Diseases
|
3.8
|
7.5
|
5.7
|
12
|
Other Injuries
|
5.7
|
1.9
|
0.0
|
13
|
Other Non-communicable Diseases
|
3.8
|
20.8
|
17.0
|
14
|
Pneumonia
|
3.8
|
0.0
|
0.0
|
15
|
Prostate Cancer
|
5.7
|
0.0
|
3.8
|
16
|
Stomach Cancer
|
1.9
|
1.9
|
1.9
|
17
|
Stroke
|
5.7
|
7.5
|
3.8
|
18
|
Undetermined
|
7.5
|
0.0
|
0.0
|
19
|
Diabetes
|
0.0
|
3.8
|
0.0
|
20
|
Leukemia/Lymphoma
|
0.0
|
1.9
|
1.9
|
21
|
Other Cancers
|
0.0
|
17.0
|
13.2
|