Prioritizing non-communicable diseases in the post-pandemic era based on a comprehensive analysis of the GBD 2019 from 1990 to 2019

This study aimed to assess the burden of communicable diseases (CDs) and non-communicable diseases (NCDs) globally, regionally, and nationally from 1990 to 2019, and propose global strategies to transform the public health policy. Using data from the Global Burden of Disease Study (GBD) 2019, we analyzed CDs and NCDs across various factors such as sex, age, year, and location, and evaluate the temporal trends of these diseases with joinpoint analysis. We also examined the differences between regions based on their socio-demographic index (SDI). In 2019, there were 7,862,907 (95% uncertainty interval [UI], 7,183,475 to 8,654,104) deaths from CDs and 42,034,124 (40,081,323 to 43,942,475) deaths from NCDs recorded worldwide. The low SDI region had markedly high age-standardized death and DALY rates of CDs. Although the age-standardized incidence rate of CDs has decreased in about half of the regions since 1990, NCDs have been on the rise in most regions. Over the past 30 years, the global burden of CDs has decreased significantly, while the burden of NCDs has aggrandized to an extent. In the post-pandemic era, effective interventions and cooperation among countries should be promoted to allocate medical resources more reasonably and improve healthcare for NCD patients.

Software.This article utilized RStudio, an integrated development environment (IDE) for the R programming language, version 4.2.0, for creating visualizations, and relies on specific R packages, such as dplyr, ggplot2, reshape2, ggmap, rgdal, maps, pheatmap, and more.

Results
Global burden of communicable diseases.In 2019, there were a total of 26,129,005,559 (24,320,309,554 to 28,173,220,203) new cases of CDs, out of which 7,862,907 (7,183,475 to 8,654,104) resulted in death, 3,142,340,323  (3,073,416,265 to 3,213,648,653) were prevalent cases and 420,392,536 (459,373,669 to 384,040,485) were cases of disability-adjusted life years (DALYs) (Table 1).The incidence, death, and DALY rates of CDs were higher in men than women, while the prevalence was slightly higher in women (Table 1).Furthermore, the < 20 years age group had the highest number of incident cases across all age groups, which remained relatively stable (Supplementary Fig. 1).
In the past 30 years, there has been a global decrease in age-standardized death, prevalence, and DALY rates of CDs.As showed in Fig. 1, the global age-standardized death rate (ASDR) decreased most significantly between the year 2006 and 2016 (APC = − 4.04%; [95% CI − 4.10% to − 3.97%]; p < 0.001).However, the global age-standardized incidence rate (ASIR) initially decreased and then increased (Fig. 1).

Global burden of non-communicable diseases.
In 2019, there were 13,065,679,568 (12,535,051,312 to 13,611,832,793) new cases of NCDs, 42,034,124 (40,081,323 to 43,942,475) deaths, 7,104,354,703 (7,040,626,561 to 7,163,713,567) prevalent cases and 1,620,165,811 (1,429,471,142 to 1,816,695,861) cases of DALYs (Table 2).Women had higher incidence and prevalence rates of NCDs than men, while men had slightly higher death and DALY rates (Table 2).In terms of age groups, the highest number of incident cases was observed in the < 20 years age group, whereas the lowest was observed in the > 80 years age group.Overall, there was an upward trend (Supplementary Fig. 1).
In the period from 1990 to 2019, there was a substantial decline in the age-standardized death and DALY rates of NCDs worldwide.Notably, as depicted in Fig. 1, the global ASDR decreased most significantly between 2003 and 2007 (APC = − 1.69%; [95% CI − 2.05% to − 1.32%]; p < 0.001).However, trends in global ASIR and age-standardized prevalence rate (ASPR) were relatively unstable with slight rate fluctuations (Fig. 1).Since 1990, there were no significant changes in age-standardized incidence and prevalence rates across all SDI quintiles.However, the decline in ASDR and DALY rates was substantial, with countries with high SDI exhibiting the greatest decline (Supplementary Fig. 2).In contrast, the upward trend in ASIR and ASPR was more pronounced in high and high-middle SDI countries in recent years (Supplementary Fig. 2).

The burden of different communicable diseases.
In line with the previous study 10 , lower respiratory infections were found to account for the highest number of deaths and DALYs among CDs in 2019.However, diarrhea and tuberculosis were the leading causes of incident and prevalent cases, respectively (Supplementary Table 5, Fig. 6, and Supplementary Figs.3-5).The other three common causes of death from CDs were diarrhea, tuberculosis, and HIV/AIDS (Supplementary Table 5).Figure 7 illustrates the global and regional rankings of different CDs based on the number of deaths, while incident cases, prevalent cases, and DALYs were demonstrated in Supplementary Figs.3-5.Tetanus had the greatest decline in age-standardized incidence, prevalence, death, and DALY rate, whereas AIDS had the most significant increase over the past 30 years (Supplementary Fig. 11).
Furthermore, the burden of different CDs varied by age.In 2019, the burden of most CDs such as the number of incident cases, deaths, prevalent cases, and DALYs was highest in children aged < 20 years, with tuberculosis and AIDS being exceptions.Specifically, AIDS mainly affected the 20 to 39 age group, as shown in Supplementary Fig. 9.
The burden of different non-communicable diseases.Among the different NCDs, cardiovascular diseases were responsible for the highest number of deaths and DALYs globally in 2019.However, skin and subcutaneous diseases accounted for the largest number of incident cases, and neurological diseases accounted for the largest number of prevalent cases (Supplementary Table 6, Fig. 7, and Supplementary Figs.6-8).The other three common causes of death were cancers, chronic respiratory diseases, and diabetes and renal diseases (Supplementary Table 6).Supplementary Fig. 11 depicts the global and regional rankings of different NCDs based on the number of deaths; the rankings according to the number of incident cases, the number of prevalent cases, and DALYs were presented in Supplementary Figs.6-8.Over the past 30 years, the greatest decline in ASIR has been for cardiovascular diseases, while the greatest decline in death and DALY has been for congenital birth defects.The greatest decline in prevalence has been for chronic respiratory diseases.Nevertheless, the increases in ASIR, ASPR, and age-standardized DALY rate were the most pronounced for diabetes and renal diseases (Supplementary Fig. 12).
The relationship between age and the types of NCDs differed from that of CDs.In 2019, with the exception of congenital birth defects, hemoglobinopathies, and hemolytic anemia, the burden of most NCDs in terms of the number of incident cases, deaths, prevalent cases, and DALYs was markedly lower in the < 20 years age group than that of CDs (Supplementary Fig. 10).Most deaths caused by NCDs occurred in the 60-79 years age group.Deaths caused by nervous system diseases were mainly in the > 80 years age group, while those caused by mental disorders were mainly in the 20-39 years age group.

Discussion
Despite improvements in global health and healthcare access, there remains a significant risk of communicable disease outbreaks.Examples include the severe acute respiratory syndrome coronavirus outbreak in 2003, the Middle East respiratory syndrome coronavirus outbreak in 2012, and the ongoing pandemic of COVID-19.However, the burden of NCDs should not be underestimated.According to the 2019 Global Health Estimates, ischemic heart disease, stroke, and chronic obstructive pulmonary disease are the top three causes of death worldwide 11 .Our study found that in 2019, there were 26.1 billion new cases and 7.86 million deaths globally due to CDs, and 13 billion new cases and 42.03 million deaths due to NCDs.Certain regions, such as Southern Sub-Saharan Africa, are faced with the challenge a double burden of CDs and NCDs 12,13 .

The burden of communicable and non-communicable diseases at different levels. The global
burden of disease shows that NCDs are responsible for more deaths, prevalence, and DALYs than CDs, while the incidence of CDs is higher.Over time, the age-standardized death, prevalence, and DALY rate of CDs have decreased significantly, and incidence has also shown a declining trend, although it has demonstrated signs of increasing in recent years.Age-standardized death and DALY rate for NCDs have also decreased, consistent with previous study 14 , but the incidence and prevalence have fluctuated and kept increasing in recent years.When focusing on absolute values, due to population growth, the number of incident and prevalent cases of both CDs and NCDs has increased each year, while the number of deaths and DALYs due to CDs has decreased each year, and the number of deaths and DALYs due to NCDs increased each year, which is consistent with the research findings of Christopher et al. in 2013 15 .The burden of CDs is mainly concentrated in the younger age group (< 20 years old), while the burden of incidence and prevalence of NCDs is mainly concentrated in younger age group (< 20 years old), and the burden of death and DALY is mainly concentrated in older age groups (60-79 years old and > 80 years old).
At regional and national levels, the burden of both CDs and NCDs was found to be higher in the African region and countries, especially in Sub-Saharan Africa, while the burden was lower in North America, East  18 .
Our study found that diarrhea was the CD with the highest burden, while cardiovascular diseases were the NCD with the highest burden, as estimated by four different comprehensive evaluation methods.Diarrhea is a leading cause of incidence and death among infants and young children worldwide, particularly in developing countries 19 , and rotavirus is the the most common cause of pediatric diarrhea 20 .Our study showed that globally, there were approximately 1.53 million deaths due to diarrhea in 2019 across all age groups.However, the burden of diarrhea incidence is even greater.Inadequate hygiene, sanitation, and access to clean water are major risk factors for the high burden of diarrheal diseases in developing countries 20,21 .Furthermore, some studies suggest that climate change may exacerbate the risk of diarrheal diseases, particularly in areas with heavy rainfall and high temperatures 22,23 .
Several bacterial, viral, parasitic, fungal, and non-communicable diarrheal agents have been identified, but 30% to 40% of diarrheal cases remain undiagnosed 19 .Shigella infection is a major cause of diarrheal deaths in children in low-and middle-income countries 24,25 .Cholera, caused by Vibrio cholerae, is another severe diarrheal disease that can quickly become fatal if left untreated.It is usually transmitted through contaminated water and human-to-human contact, and is most prevalent in the Ganges Delta of the Bay of Bengal, Bangladesh and India 26,27 .As previously reported by Roth et al., cardiovascular diseases, particularly ischemic heart disease and stroke, remain the leading cause of death and disability worldwide 28 .Our study also found that in 2019, the number of deaths due to cardiovascular disease globally across all age groups was about 18.56 million.Feigin et al. 's study on stroke similarly revealed that although the incidence, prevalence, death, and DALYs of stroke tended to decrease from 1990 to 2013, the overall burden of stroke in terms of the absolute number of people affected or disabled by stroke among men and women of all ages worldwide continued to increase 29 .

The burden of communicable and non-communicable diseases and SDI. The SDI is calculated
as the geometric mean of three indices: the total fertility rate under the age of 25 (TFU25), the average education level of the population aged 15 years and older (EDU15 +) and the lagged distributive income per capita (LDI) index.Our study found that there was a significant association between the burden of CDs and NCDs and SDI.Specifically, the age-standardized incidence, death, prevalence, and DALY rates of CDs decreased with an increase in SDI.However, the relationship between these indicators of NCDs and SDI was not as clear-cut.Although the overall trend was decreasing with an increase in SDI, there were significant regional differences.
In terms of the time span, it is noteworthy noting that since 2010, the ASIR for both CD and NCDs has increased in all SDI countries, while the ASPR for NCDs has also increased, especially for high and high-middle SDI regions.Previous studies have found that the decline in age-standardized DALY rate for NCDs has accelerated over the past decade in countries with lower SDI, while improvements have started to plateau or even reverse in countries with higher SDI 30 .This is consistent with the findings of our study (Supplementary Fig. 2).In addition, Roth et al. likewise pointed out that there is a concern that the age-standardized rate burden of cardiovascular disease is starting to rise in places where it had previously declined in high-income countries 28 .

COVID-19 and SDI.
Due to the ongoing COVID-19 pandemic, we conducted further research to investigate whether COVID-19 aligns with the patterns of CDs observed in our previous study.We gathered data on the number of COVID-19 cases and deaths in various countries for the years 2020 and 2021 from "Our World in www.nature.com/scientificreports/Data" (https:// ourwo rldin data.org/ coron avirus).As the most recent SDI data was unavailable, we used the grey prediction method to forecast the SDI data for each country in 2020 and 2021, based on the SDI data from 1990 to 2019. Figure 8 illustrates the relationship between COVID-19 burden and SDI across all countries worldwide.The results shown in Fig. 5 indicate that unlike many other CDs, COVID-19 has a higher incidence rate and mortality rate in some countries with high SDI.In the case of the United States, it is speculated that the reason for this may be related to the continued community transmission due to insufficient COVID-19 vaccination 31 .Additionally, some experts have suggested that the ideology of medical freedom related to political extremism could have contributed to the high number of deaths caused by severe acute respiratory syndrome coronavirus-2 32 .
Epidemiological transition.In this study, we have revealed that the global burden of NCDs is greater than that of CDs, which is consistent with the idea of epidemiological transformation proposed by some previous studies [33][34][35] .According to the GBD 2019 study by Stroke Collaborators, a growing portion of the global population is reaching the end of the epidemiological transition, where the risk burden has shifted toward metabolic risk factors and an increasing proportion of the disease burden is driven by stroke and other NCDs 33 .Sawyer et al. reported that the epidemiological transition to NCDs is characterized by an increasing age of disease burden across the life course 35 .Mercer, in his study of the epidemic transition model, pointed out that the major feature of the epidemiological transition is the shift of recorded causes of death from CDs to other morbid diseases 36 .Over the past 30 years, China has completed the epidemiological transition from CDs to NCDs 37 .Wong et al. also reported in their study of cirrhosis in the Asia-Pacific region that mortality due to Hepatitis B virus infection is decreasing, whereas the prevalence and incidence of fatal liver disease due to metabolic syndrome and non-alcoholic fatty liver disease continue to increase 38 .The shift in disease status from CDs to NCDs in LMICs has led to the inclusion of NCDs in the 2030 Agenda for sustainable development.However, the healthcare systems of these countries are not adequately prepared to deal with the high epidemic and economic costs of chronic diseases 39 .These aforementioned points emphasize the importance of controlling and preventing NCDs.
Current situation and strategies.In the early days of the pandemic, a WHO assessment found that 94% of countries reported that some or all of their Ministry of Health staff working on NCDs had been reassigned to work on COVID-19.This, coupled with intermittent lockdowns and high infection rates, exacerbated the strain on the healthcare system, leading to a substantial decline in screening and treatment for NCDs.In fact, cancer registration and screening declined rapidly in many countries, even in those with low COVID-19 incidences, such as New Zealand, where cancer registration had decreased by almost 40% 40 .Sheldon et al. argued in their study that the exclusive focus on COVID-19 had obscured another, less obvious epidemic 41 .Every year, NCDs such as obesity, diabetes, heart disease, stroke, cancer, chronic respiratory diseases, and mental health disorders cause more premature deaths and suffering than COVID-19.A report from Italy showed that the majority (96.2%) of patients who died from COVID-19 had comorbidities, mainly other NCDs 42 .Chan et al. also reported that in developed countries, the pressure of managing the acute effect of COVID-19 on health systems had increased the existing burden of chronic NCDs or long-term conditions 43 .During the same time, Natalie Dean, a biostatistician at Emory University in Atlanta, Georgia, warned that the Omicron variant was spreading far beyond the detection capacity of many countries, the novel coronavirus virus could continue to spread for a long time in the future, and the threat of new variants is imminent 44 .These findings are consistent with the results of Yadav et al., who suggested that COVID-19 and NCDs bidirectional relationship, whereby NCDs increase vulnerability to COVID-19, and COVID-19 increases the risk factors associated with NCDs 45 .Therefore, developing a reasonable and sound healthcare system, as well as adjusting policies, is crucial.
In this study, diarrhea, a communicable disease, was found to have the highest burden.A meta-analysis conducted by Wolf et  There may be some problems with the regional partition, albeit it was not the focus of the present study.water and improved sanitation could effectively reduce the burden of mortality and morbidity due to diarrhea in children in India.Therefore, expanding access to tap water and improving sanitation could significantly and equitably reduce the burden of diarrhea in children in India 46 .Troeger et al. also highlighted the importance of prioritizing the introduction of vaccines and interventions to decrease diarrhea-related morbidity and mortality 47 .It is crucial not to neglect the issue of NCDs, even amidst the pandemic.Building resilient healthcare systems that can treat NCDs during and after the pandemic, especially by expanding diagnostic capacity, is essential 40 .To decrease NCDs-related mortality, primary prevention should address underlying causes, and secondary prevention should ensure early detection and effective management.Detection and tracing of COVID-19 cases is similar to that of other NCDs, where concerted action is required to detect and manage cases early 41 .Monitoring social changes and inequalities exacerbated by COVID-19 is crucial for predicting downstream consequences of NCDs 48 .Nikoloski et al. reported that patients with chronic diseases are advised to continue their existing treatment for their conditions, as they are more likely to be affected by COVID-19 49 .Abolfazl Avan et al. proposed that, to reduce inequalities in stroke care, social and economic policies should be a health priority, especially in less affluent countries 50 .Telemedicine and virtual visits should receive more attention.Takahashi et al. also reported that telehealth can provide health services remotely through telecommunication technology and has had a significant effect on the evolving medical landscape 51 .Recent research has revealed the importance of an active lifestyle and regular exercise, as physical inactivity is a focal modifiable risk factor for many NCDs and mental health conditions 52 .

Conclusions
The COVID-19 pandemic has created unprecedented challenges to the global healthcare system, especially in managing NCDs.It is essential to develop resilient healthcare systems capable of treating NCDs, expanding diagnostic capacity, and prioritizing the introduction of vaccines and interventions to reduce disease-related morbidity and mortality.Additionally, addressing underlying causes and promoting primary prevention of NCDs, as well as monitoring social changes and inequalities exacerbated by COVID-19, are also critical steps towards improving global health outcomes.

Figure 6 .
Figure 6.Global and regional communicable diseases ranked by the total number of deaths in 2019.

Figure 7 .
Figure 7. Global and regional non-communicable diseases ranked by the total number of deaths in 2019.

Figure 8 .
Figure 8. Scatter plot of the relationship between COVID-19 and the predicted SDI in 2021 and 2022.(a) The relationship between COVID-19 incident cases and the predicted SDI; (b) the relationship between COVID-19 deaths and the predicted SDI.

Table 2 .
Global burden of non-communicable diseases in 2019.
Vol.:(0123456789) Scientific Reports | (2023) 13:13325 | https://doi.org/10.1038/s41598-023-40595-7www.nature.com/scientificreports/ Figure 2. Regional age-standardized incidence rates (per 100,000 population) of communicable disease in 2019 and their sex-specific percentage changes from 1990 to 2019.(a) age-standardized incidence rate in 2019; (b) percentage change in age-standardized incidence rate, 1990-2019; (c) age-standardized death rate in 2019; (d) percentage change in age-standardized death rate, 1990-2019; (e) age-standardized prevalence rate in 2019; (f) percentage change in age-standardized prevalence rate in 2019; (g) age-standardized DALY rate in 2019; (h) percentage change in age-standardized DALY rate, 1990-2019.DALY disability-adjusted life year.Asia, and Oceania, although North America had a slightly higher ASIR for CDs.Over the past 30 years, the agestandardized incidence rate of about half of the regions with CDs have shown a downward trend, while most of the NCDs have shown an upward trend.Other indicators such as ASDR, ASPR and age-standardized DALY rate have shown a downward trend in most areas.Previous studies have highlighted the increasing burden of disease in Africa, such as Bigna et al. who pointed out that the burden of NCDs in Sub-Saharan Africa has dramatically increased in the past 20 years 16 , Gouda et al. who also stated that NCDs in Sub-Saharan Africa pose an increasing challenge to health systems 17 and Modjadji et al. who had described the challenge of addressing multiple disease burdens in Africa, characterized by high rates of CDs such as HIV, AIDS, and tuberculosis, as well as NCDs such as cardiovascular disease and diabetes al. suggested that interventions such as high-quality drinking water and filtered water at pointof-use could reduce the risk of diarrhea by approximately 50% 21 .In addition, Nandi et al. suggested that clean tap Figure 4. National age-standardized rates (per 100,000 population) of communicable diseases and NCDs in 2019.(a) The age-standardized incidence rate of communicable diseases; (b) age-standardized incidence rate of non-communicable diseases; (c) age-standardized death rate of communicable diseases; (d) age-standardized death rate of non-communicable diseases; (e) age-standardized prevalence rate of communicable diseases; (f) age-standardized prevalence rate of non-communicable diseases; (g) age-standardized DALYs rate of communicable diseases; (h) age-standardized DALYs rate of non-communicable diseases.DALY disabilityadjusted life year.The original data was obtained from the GBD studies.