Causes of admissions and in-hospital mortality among patients admitted to critical care units in primary and secondary hospitals in Vietnam in 2018: a multicentre retrospective study

Objective The goal of this study was to describe the burden of disease and in-hospital mortality among patients admitted to the critical care units (CCUs) in Vietnam. Design Retrospective study. Setting The whole 1-year data of admissions to CCUs were collected from 34 hospitals from January to December 2018. Participants A total of 44 013 episodes of admission to CCUs were analysed. Primary outcome We used International Classification of Diseases-11 codes to assess the primary diagnosis associated with admissions and in-hospitals mortality. Years of life lost (YLL) measure was further used to estimate the burden of disease. Results The 0–5 years and ≥70 years age groups accounted for 14.8% (6508/44 013) and 26.1% (11 480/44 013) of all admissions, respectively. The most common diagnoses were diseases of the respiratory system (27.8% or 12 255/44 013), followed by unclassified symptoms, signs or clinical findings (13% or 5712/44 013), and diseases of the circulatory system (12.2% or 5380/44 013). Among 28 311 patients with available outcome data, 1681 individuals (5.9%) died during the hospitalisation. The in-hospital mortality rate increased with age, from 2.8% (86/3105) in under 5 years old age group to 23.1% (297/1288) in over 90-year age group. Diseases of the respiratory system was the leading causes of death in term of number of deaths (21.8% or 367/1681 of all deaths). Diagnosis of sepsis was associated with the highest in-hospital mortality (36.8%). The overall YLL under the age of 75 were 1287 per 1000 patients. Conclusions CCUs in Vietnam faced wide differences in the burden of diseases. Sufficient infrastructure and adequate multidisciplinary training are essential to ensure the appropriate response to the current needs of population.


Asan medical center, emergency medicine REVIEW RETURNED
13-Apr-2022

GENERAL COMMENTS
Authors were to describe the frequency of diagnostic categories, in-hospital mortality, cause of death and the burden of premature mortality in CCUs of Vietnam in 2018. In general, the context and motivation for this research is relatively weak, and the problem to be solved by the research is relatively vague. These are just descriptive statistics. Although the information appears to be rich, the accuracy and reliability of diagnosis description or diagnostic coding is limitation. In the conclusions section, representation should be linked to the research findings that served.
1. This study mainly focuses on the diagnosis, mortality, and causes of death in patients admitted to CCU. Were the patients included regardless of the route of hospitalization? (e.g., admission from outpatient department, or emergency department, or general ward) If they were, it may be appropriate to revise the wording of emergency department and emergency care in the introduction and conclusion section. Current tone may confuse readers that this study focuses on health care in the emergency department.
2. What is the definition of "going home to die imminently after hospital discharge"? Please describe the definition in the methods section.
3. Please describe the definitions of provincial and district hospital in the methods section. And It may be more appropriate to describe functional differences between the hospitals in the methods section, rather than in the discussion section.
4. Approximately 40% of patients were missing from the outcome analysis. Considering the purpose of this research, it is important to investigate the outcomes of the included patients. A large number of missing values could compromise the integrity of conclusions. Please explain the main reasons of missing data in the methods section. If the mortality rate has increased compared to previous studies due to the missing data, please describe it as a study's limitation also.
5. In table 1, which ICD codes were included in "miscellaneous" category? It should be described or discussed in detail because it is the second largest proportion of death cases.
6. The authors presented data as background information that the burden of non-communicable disease has increased since 1990. The reduction of communicable disease may depend on changes in the medical/social environment such as available resource, health care policy, etc. However, the authors concluded that the preparedness for infectious diseases is important as they are increasing. Please describe why the authors mentioned the increase in non-communicable diseases at the outset.
7. The authors concluded that respiratory and infectious diseases became a high burden of illness in emergency care in Vietnam. However, this interpretation may vary depending on the data presented. In terms of block level 1 code, cerebrovascular diseases and sepsis show the highest number of death and mortality, respectively (table 1). Otherwise, in terms of disease classification, respiratory diseases and neoplasms show the most (supp table 1). I think that the authors should revise the conclusion section reflecting those differences.
8. There are no specific proposals or suggestions derived from the results of current study. Please add a paragraph in the discussion section about the application of the research finding in clinical practice and future research to compliment the limitations of current study.
9. In the conclusion section, the authors mentioned that the medical needs varied by age group, but a detailed interpretation of the conclusion was not included in the discussion section. Our response: We recorgnized the importance of the ethics aspect and stated that "This study was approved by the institutional review board (IRB) in the Hanoi Medical University (59/GCN-DDNCYSH-DHYHN)". Please see the "Ethics approval" section.

The paper is nicely contextualised within the global burden of disease study and the use of YLL is a valuable addition to the literature on burden of disease in Vietnam.
Our response: Thank you.

Because of its reliance on coding the paper is a little light on clinical conditions, particularly postoperative critical care, which is quite influential on the outcomes of patients treated in CCU's. This information would be helpful. Given the authors have the codes, I wonder whether a table of actual conditions (eg I can see head injuries but I can't see acute abdominal pathology/post emergency laparotomy, or specific fractures within the injury list). Could some of the system diagnoses have supplementory tables that cover actual conditions as opposed to broad groups?
Our response: Thank you, we have provided the details of the actual conditions using ICD-11 4 character codes in death cases in the Supplementary table 2.

present both if available, otherwise death at discharge from hospital is the most valuable which is what I think Fig 1 refers to given your statement on this in the methods section.
Our response: Thank you. We provided the data on the survival and death at discharge from hospital. We have revised the text in the figure 1 for the clarity.
5 Similar to my comment on emergency laparotomy, it is not clear to me from the paper what treatments were available. One assumes a CCU has ventilation, inotropes, haemofiltration available, but perhaps this is not true in all district hospitals.
Our response: Thank you for poiting that out. We agree that it is important to understand the availability of diagnostics and treatment. At the time collecting the data, we conducted a concurrent survey of capacity and use of diagnostics and treatment for patients with severe acute respiratory infections in Viet Nam. There were significant differences between district and provincial hospitals in the availability of microbial culture, rapid influenza diagnostic tests, inflammatory markers and mechanical ventilation. We published the survey results at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8873919/. As your advised, we have added the below texts about these differences and cited the above-mentioned article in the discussion. "In 2019, we conducted a survey on the capacity and use of diagnostics and treatment for patients with severe acute respiratory infections in 48 hospitals in Vietnam (including 32 hospitals in this study) at the same time as this study. Significant differences were observed in the district hospitals when compared to provincial hospitals in regards to availability of the microbiological diagnostics (9.4% vs 81.2%, p<0.001), inflammatory markers of C-reactive protein (31.2% vs 54.2%, p<0.001) and procalcitonine (3.1% vs 25%, p<0.001) and mechanical ventilation (40.6% vs 60.4%, p<0.001)" 6 If you are going to limit this paper to the burden of disease your discussion needs to discuss treatment facilities, and also progress to treatment cost-effectiveness. A follow up paper to recommend would be the cost effectiveness of CCU in Vietnam -how much did it cost to save a life year or 10 life years? Are there recommendations to be made around improving facilities?
Our response: Thank you, this comments is important and helpful to the study team for future study. We would like to incorperate your comment in our manuscript as below: "Currently, there is limited cost-effectiveness analysis performed for critical care services in Vietnam.
The results of this study in regards to the a variety of diagnoses and outcomes of admission will direct the future studies on the establishment of CCU registry, the effectiveness of CCU treatments and estimates of the total cost to save a life-year. This information will be helpful to develop policies and strategies to make better-informed decisions in resource-constrained settings in the face of an aging population in Vietnam." Reviewer: 2 Dr. won young kim, Asan medical center Comments to the Author: Authors were to describe the frequency of diagnostic categories, in-hospital mortality, cause of death and the burden of premature mortality in CCUs of Vietnam in 2018. In general, the context and motivation for this research is relatively weak, and the problem to be solved by the research is relatively vague. These are just descriptive statistics. Although the information appears to be rich, the accuracy and reliability of diagnosis description or diagnostic coding is limitation. In the conclusions section, representation should be linked to the research findings that served.

This study mainly focuses on the diagnosis, mortality, and causes of death in patients admitted to CCU. Were the patients included regardless of the route of hospitalization? (e.g., admission from outpatient department, or emergency department, or general ward) If they were, it may be appropriate to revise the wording of emergency department and emergency care in the introduction and conclusion section. Current tone may confuse readers that this study focuses on health care in the emergency department.
Our response: Thank you, in our study, we included all patients regardless of the rout of hospitalization. According to Vietnam government's regulations, an emergency department (ED) is a medical treatment facility which admits and treats all patients with emergency conditions referred to the hospital. Its function is to assess, triage and provide appropriate management by priority level of emergency until the patient is no longer in a serious condition and then within 48 h must transfer the patient to an Intensive care unit (ICU) or an appropriate medical ward when patient's status allow. An ICU is a clinical department responsible for providing continuous critical care for patients who are transferred from an ED or clinical wards of the hospital. Because many provincial and district hospitals cannot establish separated ED and ICU, we used the terms critical care unit (CCU) is referred to emergency departments (EDs) or intensive care capable EDs as we briefly described in the introduction.

What is the definition of "going home to die imminently after hospital discharge"? Please describe the definition in the methods section.
Our response: Thank you, we have added the definition for the clarity. Palliative discharge is a common practice in Vietnam, patients prefer to die at home. Thus when they are in a moribund state they often request discharge. As this is a retrospective study of routine care we are not able to comment on whether such patients did indeed pass away, however from experience it is unlikely that these patients remained alive for any length of time. Palliative discharges have been considered as inpatient deaths in a number of previous studies from this setting by our group and others ( We have added the below text "Palliative discharge is a common practice in Vietnam when a patient is in a moribund state and expresses a wish to die at home".

Please describe the definitions of provincial and district hospital in the methods section.
And It may be more appropriate to describe functional differences between the hospitals in the methods section, rather than in the discussion section.
Our response: Thank you, we agree that it is important to describe the functions of difference level of care. However, we would like to describe these differences next to the discussion of variation of disease by levels of hospital to help readers having some ideas about the reason why there were difference in causes of admission in district and provincial hospitals.

Approximately 40% of patients were missing from the outcome analysis. Considering the purpose of this research, it is important to investigate the outcomes of the included patients. A large number of missing values could compromise the integrity of conclusions. Please explain the main reasons of missing data in the methods section. If the mortality rate has increased compared to previous studies due to the missing data, please describe it as a study's limitation also.
Our response: we would like to confirm that only 26.5% (10,223/38543) of patients were missing from the outcome analysis (figure 1). We recognized that the missing data can produce biased. We have revised the discussion of limitation as below: "Another limitation was the missing information on outcome for 26.5% (10,223/38543) of patients because these were not actually entered into the electronic hospital management system. This missing data can cause bias in the estimation of in-hospital mortality"

In table 1, which ICD codes were included in "miscellaneous" category? It should be described or discussed in detail because it is the second largest proportion of death cases.
Our response: Thank you, it is also a comment from another reviewer. We have added the appendix to provide the details of miscellaneous causes (the supplementary table 2).
6. The authors presented data as background information that the burden of noncommunicable disease has increased since 1990. The reduction of communicable disease may depend on changes in the medical/social environment such as available resource, health care policy, etc. However, the authors concluded that the preparedness for infectious diseases is important as they are increasing. Please describe why the authors mentioned the increase in non-communicable diseases at the outset.
Our response: Thank you for this comment. In general, the burden of non-communicable decreased as measured in the DALY between 2000 and 2017. However, our analysis showed that the burden of infectious diseases was significant in CCUs in term of number of admission (27.8% of all admission episodes) and this measure was not well reported before. It reflected the fact that a single measure is not enough. We described the admission in Vietnam in 2018 and in the context of the emergence of COVID-19, we believed that the preparedness for the threats of infectious diseases in the future is important.
7. The authors concluded that respiratory and infectious diseases became a high burden of illness in emergency care in Vietnam. However, this interpretation may vary depending on the data presented. In terms of block level 1 code, cerebrovascular diseases and sepsis show the highest number of death and mortality, respectively (table 1). Otherwise, in terms of disease classification, respiratory diseases and neoplasms show the most (supp table 1). I think that the authors should revise the conclusion section reflecting those differences.
Our response: Thank you, I agreed that the interpretation may vary depending on the measures which is used to present the data. I have removed the statement of infectious diseases from the conclusion. Please read as "Our study indicates a variation of needs of emergency care by age groups and levels of care among patients admitted to CCUs in provincial and district hospitals in Vietnam" 8. There are no specific proposals or suggestions derived from the results of current study. Please add a paragraph in the discussion section about the application of the research finding in clinical practice and future research to compliment the limitations of current study. Our response: Thank you, we appreciated this comment which is aligned with another reviewer's comment. We have added the below text for the future research: "Currently, there is limited cost-effectiveness analysis performed for critical care services in Vietnam.
The results of this study in regards to the a variety of diagnoses and outcomes of admission will direct the future studies on the establishment of CCU registry, the effectiveness of CCU treatments and estimates of the total cost to save a life-year. This information will be helpful to develop policies and strategies to make better-informed decisions in resource-constrained settings in the face of an aging aged population in Vietnam." 9. In the conclusion section, the authors mentioned that the medical needs varied by age group, but a detailed interpretation of the conclusion was not included in the discussion section. Fig 2 and 3 look fancy with color graphs, however, they only show the obvious and expected results of this study. Please add more detailed interpretations of the distribution of diagnoses and mortality by age groups in the discussion section.
Our response: Thank you, in the result section, we tried describing the distribution of diagnoses and outcomes by age groups and the conclusion came directly from the result. We recognized that this