The Impact of Macroeconomic Factors on Mortality from Non-Communicable Diseases: Evidence from Azerbaijan
, Masim Abadov 1, Vugar Gapagov 2, Irada Mehdiyeva 4 and Jeyhun Mahmudov 5
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
Given the extreme relevance of the topic, especially in the type of countries considered in the study, I would very much like to be able to recommend the publication of the manuscript, even if it is eventually subject to minor revisions. Unfortunately, I cannot do so, for the following reasons:
- Although it is not the most substantial reason, I begin by noting that the manuscript presents some statements that seem difficult to me to understand. As an example, consider the sentence: “The probability of dying between the exact ages of 30 and 70 from any of these conditions (%), known as the "Mortality" indicator, [...]” (19-20). The sentence suggests that, when we talk about the mortality indicator, whatever it may be, it is that probability that we are talking about.
- Continuing with the variable of interest, why was the age group from 30 to 70 years considered? Is there no mortality due to cardiovascular diseases, cancer, diabetes, and chronic respiratory diseases for ages under 30 or over 70 years?
- Continuing with the variable of interest, dealing with a probability, i.e. limited, between 0 and 1, I have many doubts that the estimated models are adequate. To do so, it would be enough to check the predicted values for those probabilities. Would these values make sense from the point of view of their mathematical domain?
- Moving on to the potential explanatory variables, I believe there are strong reasons for the existence of multicollinearity problems between them. As an example, one of the explanatory variables is the Human Development Index. Now, as is known, in the calculation of this index, the level of Gross Domestic Product per Capita is used, which was also considered as another explanatory variable. What is the correlation coefficient between these two variables? It should be reasonably high.
- I also consider that the literature review is too short. I am well aware that the literature on the subject is enormous and therefore any review will be incomplete. Still, more effort clearly should have been put into this part of the manuscript.
- As for the discussion of the results, I also believe that the authors could have gone further.
- Also, in the conclusive section, the limitations of the study were not mentioned.
Author Response
Open Review (x) I would not like to sign my review report
( ) I would like to sign my review report Quality of English Language ( ) The English could be improved to more clearly express the research.
(x) The English is fine and does not require any improvement.
| Yes | Can be improved | Must be improved | Not applicable | |
| Does the introduction provide sufficient background and include all relevant references? | ( ) | ( ) | (x) | ( ) |
| Is the research design appropriate? | ( ) | ( ) | (x) | ( ) |
| Are the methods adequately described? | ( ) | (x) | ( ) | ( ) |
| Are the results clearly presented? | ( ) | (x) | ( ) | ( ) |
| Are the conclusions supported by the results? | ( ) | ( ) | (x) | ( ) |
Comments and Suggestions for Authors
Given the extreme relevance of the topic, especially in the type of countries considered in the study, I would very much like to be able to recommend the publication of the manuscript, even if it is eventually subject to minor revisions. Unfortunately, I cannot do so, for the following reasons:
- Although it is not the most substantial reason, I begin by noting that the manuscript presents some statements that seem difficult to me to understand. As an example, consider the sentence: “The probability of dying between the exact ages of 30 and 70 from any of these conditions (%), known as the "Mortality" indicator, [...]” (19-20). The sentence suggests that, when we talk about the mortality indicator, whatever it may be, it is that probability that we are talking about.
- Continuing with the variable of interest, why was the age group from 30 to 70 years considered? Is there no mortality due to cardiovascular diseases, cancer, diabetes, and chronic respiratory diseases for ages under 30 or over 70 years?
- Continuing with the variable of interest, dealing with a probability, i.e. limited, between 0 and 1, I have many doubts that the estimated models are adequate. To do so, it would be enough to check the predicted values for those probabilities. Would these values make sense from the point of view of their mathematical domain?
- Moving on to the potential explanatory variables, I believe there are strong reasons for the existence of multicollinearity problems between them. As an example, one of the explanatory variables is the Human Development Index. Now, as is known, in the calculation of this index, the level of Gross Domestic Product per Capita is used, which was also considered as another explanatory variable. What is the correlation coefficient between these two variables? It should be reasonably high.
- I also consider that the literature review is too short. I am well aware that the literature on the subject is enormous and therefore any review will be incomplete. Still, more effort clearly should have been put into this part of the manuscript.
- As for the discussion of the results, I also believe that the authors could have gone further.
- Also, in the conclusive section, the limitations of the study were not mentioned.
The concerns raised by the reviewer are very reasonable. In response to the first concern, namely the question "Why was the age range of 30-70 years considered?", we would like to clarify that the most reliable indicators for measuring mortality from non-communicable diseases include "Life expectancy," "Under-five mortality rate," "Maternal mortality rate," "Prevalence of chronic diseases," and "Probability of dying between exact ages 30 and 70 from any of cardiovascular disease, cancer, diabetes, or chronic respiratory diseases (%)." In our research, we specifically selected the indicator "Probability of dying between exact ages 30 and 70 from any of cardiovascular disease, cancer, diabetes, or chronic respiratory diseases (%)" as a proxy for "mortality." This choice was made because the official life expectancy in Azerbaijan is approximately 70-72 years. Moreover, the majority of the economically active population falls within this age range, i.e. 30-70 years.
The reviewer is right in pointing out that there may be a correlation between HDI and GDP per capita. It should be noted that "GDP per capita" is indeed one of the components used in calculating the "HDI," and theoretically, a high correlation between them exists. However, empirically, the relationship between these two indicators in the case of Azerbaijan exhibits a different nature. Specifically, in Azerbaijan, GDP per capita is primarily influenced by oil revenues, whereas other components play a more significant role in the HDI indicator. Since "HDI" and "GDP per capita" encompass various social and economic factors, their impact on health indicators can occur through different channels. HDI's impact mechanisms are a)Better education and social development promote a healthy lifestyle; b) Higher life expectancy reflects the development of the healthcare system; c) As human development increases, citizens' knowledge about health improves, and they place greater emphasis on preventive measures. GDP per capita's impact mechanisms are a) Economic growth expands financial resources for funding healthcare services and investing in higher-quality medical technologies; b)Higher income levels increase individuals' access to healthcare services. (This has been included in the text in red)
We fully agree with the reviewer's third concern regarding the study's limitations. Indeed, the use of the indicator "Probability of dying between exact ages 30 and 70 from any of cardiovascular disease, cancer, diabetes, or chronic respiratory diseases (%)" as a proxy for "Mortality" is itself a limitation of the study. This is because the fact that this indicator only covers the age range of 30-70 can be considered a constraint in the research. (This has been included in the text in red)
Reviewer 2 Report
Comments and Suggestions for Authors
Introduction
There is literature indicating that non-communicable diseases (such as cardiovascular conditions, diabetes, and other chronic illnesses) are genetically transmissible. The authors should specify the type of heritability to which they are referring. Recommended reading: https://www.who.int/news-room/fact-sheets/detail/noncommunicable-diseases. A definition of non-communicable diseases (NCDs) should be provided. It is also important to clarify for readers outside the field of health economics which data will be used in the study.
The objective of the article lacks clarity.
The Fourth Hypothesis: An increase in out-of-pocket healthcare expenses increases mortality from NCDs requires reconsideration. Are there more deaths because healthcare expenses increased, or did expenses rise due to an increase in deaths? Both may be valid, but the authors leave room for ambiguity in the introduction. This point should be reviewed.
The end of the introduction lacks a paragraph outlining the structure of the paper.
Literature
Does the literature on non-communicable diseases not present any examples for the country under study? If there are relevant examples, why have they not been cited?
The authors provide a global context by mentioning countries such as China, BRICS, and South Africa. It would be valuable to also reference neighbouring countries to the case study.
"Several studies have established a robust correlation between a country’s GDP per capita and the burden of NCDs." These studies must be properly cited.
"Wealthier countries often face higher rates of NCDs due to lifestyle factors such as high-calorie diets, physical inactivity, and stress. In contrast, lower-income countries experience significant NCD burdens as a result of limited healthcare access, inadequate preventive measures, and economic instability. Research suggests a U-shaped relationship, wherein both very high and very low GDP levels contribute to increased NCD prevalence, implying that both economic extremes are associated with poor health outcomes." These claims must be supported with appropriate references.
"Studies indicate that countries with high Gini coefficients tend to experience higher rates of NCD-related deaths." Again, the relevant studies must be cited.
"The literature suggests that even a 1% increase in healthcare spending as a share of GDP can substantially reduce NCD-related mortality rates, underscoring the importance of effective healthcare resource management." This statement must also be supported by references.
In the final paragraphs of the literature review, the authors omit the sources that inspired the text. These studies must be acknowledged and cited.
Suggested incorporation into the manuscript: the authors might consider including ECM (Error Correction Model) analysis and using Body Mass Index (BMI) as a relevant variable for its impact on life expectancy in Portugal, as discussed in: https://periodicos.uem.br/ojs/index.php/ActaSciHealthSci/article/view/64695
Data and Methodology
The authors should present descriptive statistics for the data to help readers better understand the nature of the variables.
A Variance Inflation Factor (VIF) test for multicollinearity should be conducted, both with variables in levels and in first differences, but only for those used in the ARDL model.
It is recommended that natural logarithms of the variables be taken, and stationarity re-checked. If necessary, differences of the logarithmic values should be used.
Additional tests for autocorrelation and heteroskedasticity are suggested, beyond the use of the Durbin-Watson statistic.
Background
This content could be integrated into the introduction and/or literature review.
Discussion
This section needs further development.
Conclusion
The conclusions should indicate which of the hypotheses presented in the introduction were confirmed.
It is important to suggest future research paths in the field of health economics for the country under study.
The limitations of the study must also be clearly presented.
Author Response
Open Review (x) I would not like to sign my review report
( ) I would like to sign my review report Quality of English Language ( ) The English could be improved to more clearly express the research.
(x) The English is fine and does not require any improvement.
| Yes | Can be improved | Must be improved | Not applicable | |
| Does the introduction provide sufficient background and include all relevant references? | ( ) | (x) | ( ) | ( ) |
| Is the research design appropriate? | (x) | ( ) | ( ) | ( ) |
| Are the methods adequately described? | ( ) | ( ) | (x) | ( ) |
| Are the results clearly presented? | ( ) | (x) | ( ) | ( ) |
| Are the conclusions supported by the results? | (x) | ( ) | ( ) | ( ) |
Comments and Suggestions for Authors
Introduction
There is literature indicating that non-communicable diseases (such as cardiovascular conditions, diabetes, and other chronic illnesses) are genetically transmissible. The authors should specify the type of heritability to which they are referring. Recommended reading: https://www.who.int/news-room/fact-sheets/detail/noncommunicable-diseases. A definition of non-communicable diseases (NCDs) should be provided. It is also important to clarify for readers outside the field of health economics which data will be used in the study.
The objective of the article lacks clarity.
The Fourth Hypothesis: An increase in out-of-pocket healthcare expenses increases mortality from NCDs requires reconsideration. Are there more deaths because healthcare expenses increased, or did expenses rise due to an increase in deaths? Both may be valid, but the authors leave room for ambiguity in the introduction. This point should be reviewed.
The end of the introduction lacks a paragraph outlining the structure of the paper.
Non-communicable diseases (NCDs) are chronic conditions that are not transmitted from person to person. They are typically the result of a combination of genetic, physiological, environmental, and behavioural factors. The major NCDs include cardiovascular diseases, cancers, chronic respiratory diseases, and diabetes. The key causes can be grouped into the following categories: a)unhealthy behaviours (e.g. tobacco use, unhealthy diet, physical inactivity, excessive alcohol consumption etc.) are the most significant contributors to NCD development; b) biological risk factors (e.g. hypertension (high blood pressure, obesity and overweight, hyperglycemia, hyperlipidemia etc.); c)environmental and social determinants (e.g. air pollution, workplace hazards, urbanisation and lifestyle shifts, social determinants etc.); d) genetic and physiological factors (e.g. family history, age and gender etc.); e) psychological and emotional factors (e.g. chronic stress, depression and anxiety etc.); f) healthcare system-related factors (e.g. inadequate access to healthcare, lack of vaccination programs etc.). (This has been included in the text in red).
The investigation aims to identify the economic factors contributing to mortality from NCD diseases and to develop recommendations for eliminating these causes. (This has been included in the text in red).
The relationship between "out-of-pocket" expenses and "mortality" is interesting. The costs required for the treatment of NCD diseases are often so substantial that "out-of-pocket" expenses do not fully cover them, and in most cases, such expenses are insufficient to ensure complete treatment. Nevertheless, the increase in expenses contributing to higher "mortality" rates is linked to the fact that, in Azerbaijan, mortality cases are predominantly attributed to NCD diseases covered by "out-of-pocket" expenses. In other words, "out-of-pocket" expenses do not increase mortality; rather, they reveal the registration of mortality cases. (This has been included in the text in red).
Literature
Does the literature on non-communicable diseases not present any examples for the country under study? If there are relevant examples, why have they not been cited?
Unfortunately, this study on the macroeconomic factors of mortality from NCD diseases is the first of its kind in the context of Azerbaijan. Conducting further research in the field of health economics in the context of Azerbaijan is essential in the future. (This has been included in the text in red)
The authors provide a global context by mentioning countries such as China, BRICS, and South Africa. It would be valuable to also reference neighbouring countries to the case study.
"Several studies have established a robust correlation between a country’s GDP per capita and the burden of NCDs." These studies must be properly cited.
This is supported by necessary references (These references have been included in the text in red)
"Wealthier countries often face higher rates of NCDs due to lifestyle factors such as high-calorie diets, physical inactivity, and stress. In contrast, lower-income countries experience significant NCD burdens as a result of limited healthcare access, inadequate preventive measures, and economic instability. Research suggests a U-shaped relationship, wherein both very high and very low GDP levels contribute to increased NCD prevalence, implying that both economic extremes are associated with poor health outcomes." These claims must be supported with appropriate references.
This is supported by necessary references (These references have been included in the text in red)
"Studies indicate that countries with high Gini coefficients tend to experience higher rates of NCD-related deaths." Again, the relevant studies must be cited.
This is supported by necessary references (These references have been included in the text in red)
"The literature suggests that even a 1% increase in healthcare spending as a share of GDP can substantially reduce NCD-related mortality rates, underscoring the importance of effective healthcare resource management." This statement must also be supported by references.
This is supported by necessary references (These references have been included in the text in red)
In the final paragraphs of the literature review, the authors omit the sources that inspired the text. These studies must be acknowledged and cited.
Suggested incorporation into the manuscript: the authors might consider including ECM (Error Correction Model) analysis and using Body Mass Index (BMI) as a relevant variable for its impact on life expectancy in Portugal, as discussed in: https://periodicos.uem.br/ojs/index.php/ActaSciHealthSci/article/view/64695
Data and Methodology
The authors should present descriptive statistics for the data to help readers better understand the nature of the variables.
(Descriptive Statistics included in the text in red)
A Variance Inflation Factor (VIF) test for multicollinearity should be conducted, both with variables in levels and in first differences, but only for those used in the ARDL model.
It is recommended that natural logarithms of the variables be taken, and stationarity re-checked. If necessary, differences of the logarithmic values should be used.
(The stationarity of the logarithms of the variables is included in the text in red)
Additional tests for autocorrelation and heteroskedasticity are suggested, beyond the use of the Durbin-Watson statistic.
Background
This content could be integrated into the introduction and/or literature review.
(This content is integrated into the introduction)
Discussion
This section needs further development.
(The discussion section has been improved)
Conclusion
The conclusions should indicate which of the hypotheses presented in the introduction were confirmed.
It is important to suggest future research paths in the field of health economics for the country under study.
(The conclusions section has been improved)
The limitations of the study must also be clearly presented.
(The limitations of the study have been included in the text in red)
Reviewer 3 Report
Comments and Suggestions for Authors
The authors write about a specific topic in the article. The article is
well structured and easy to understand. However, it would be advisable
to supplement the paper with a few questions:
- in the introduction, it should be determined for what purpose exactly
this research was conducted? Then, in the results, reflect on this: in
what circle could the results be utilized and further developed? What
measures does this mean for the countries concerned?
- in addition, I suggest supplementing the integrated literature
(especially in the presentation of the Azerbaijani healthcare system,
the integration of literature sources is moderate)
- in the methodological part, it would be advisable to present the
individual methods in more detail (detailed description), because the
methods used by the authors are rarer in the healthcare context.
Comments on the Quality of English Language
-
Author Response
Open Review ( ) I would not like to sign my review report
(x) I would like to sign my review report Quality of English Language (x) The English could be improved to more clearly express the research.
( ) The English is fine and does not require any improvement.
| Yes | Can be improved | Must be improved | Not applicable | |
| Does the introduction provide sufficient background and include all relevant references? | ( ) | (x) | ( ) | ( ) |
| Is the research design appropriate? | ( ) | (x) | ( ) | ( ) |
| Are the methods adequately described? | (x) | ( ) | ( ) | ( ) |
| Are the results clearly presented? | (x) | ( ) | ( ) | ( ) |
| Are the conclusions supported by the results? | ( ) | (x) | ( ) | ( ) |
Comments and Suggestions for Authors
The authors write about a specific topic in the article. The article is
well structured and easy to understand. However, it would be advisable
to supplement the paper with a few questions:
- in the introduction, it should be determined for what purpose exactly
this research was conducted? Then, in the results, reflect on this: in
what circle could the results be utilized and further developed? What
measures does this mean for the countries concerned?
(The purpose of the investigation has been included in the text in red)
- in addition, I suggest supplementing the integrated literature
(especially in the presentation of the Azerbaijani healthcare system,
the integration of literature sources is moderate)
Unfortunately, there is no investigation on this subject in the Azerbaijan context.
- in the methodological part, it would be advisable to present the
individual methods in more detail (detailed description), because the
methods used by the authors are rarer in the healthcare context.
You are right, there has been chosen simple econometric methods and applied to the problem. But these methods give interesting and useful results for policymakers.
Round 2
Reviewer 1 Report
Comments and Suggestions for Authors
Unfortunately, the authors ignored what would be my biggest criticism, which had to do with the suitability of the type of model estimated, given the type of variable of interest, i.e. a probability. To be clearer, I will repeat what I stated in the previous report:
- "Continuing with the variable of interest, dealing with a probability, i.e. limited, between 0 and 1, I have many doubts that the estimated models are adequate. To do so, it would be enough to check the predicted values for those probabilities. Would these values make sense from the point of view of their mathematical domain?"
Author Response
"Continuing with the variable of interest, dealing with a probability, i.e. limited, between 0 and 1, I have many doubts that the estimated models are adequate. To do so, it would be enough to check the predicted values for those probabilities. Would these values make sense from the point of view of their mathematical domain?"
Our answer to the reviewer:
The indicator "The probability of mortality due to non-communicable diseases (NCDs) among individuals aged 30–70" is usually calculated by the World Health Organization (WHO) and reflects the probability that a person aged between 30 and 70 will die from one of the four major non-communicable diseases (cardiovascular diseases, cancer, chronic respiratory diseases, and diabetes).
In the calculation:
- a) Age-specific mortality rates are collected – that is, for age groups such as 30, 35, 40, ..., 70, the number of NCD-related deaths is divided by the total population in each respective age group;
- b) These rates are aggregated across 5-year age intervals and expressed as a probability using life table methods;
- c) The resulting figure represents the probability that a person aged 30 will die from NCDs before age 70 (this value falls between 0 and 1 and is often expressed as a percentage).
This indicator is used because:
- a) It is suitable for international comparison;
- b) It reflects the risk of death, not just the number of deaths;
- c) It helps assess the effectiveness of health policies in combating NCDs.
