Evolution and effectiveness of bilateral and multilateral development assistance for health: a mixed-methods review of trends and strategic shifts (1990–2022)

Abstract

Background

Development assistance for health (DAH) plays a vital role in supporting health programmes in low- and middle-income countries. While DAH has historically focused on infectious diseases and maternal and child health, there is a lack of comprehensive analysis of DAH trends, strategic shifts and their impact on health systems and outcomes. This study aims to provide a comprehensive review of DAH from 1990 to 2022, examining its evolution and funding allocation shifts.

Methods

We conducted a mixed-methods review, adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A systematic literature search was performed across PubMed, Embase, Web of Science and the Cochrane databases, yielding 102 eligible studies. Quantitative data were obtained from the Institute for Health Metrics and Evaluation database, covering DAH data from 1990 to 2022. Qualitative data were analysed through thematic synthesis based on the WHO’s six health system building blocks.

Results

The DAH has predominantly focused on HIV/AIDS and maternal and child health. Despite the increasing global burden of non-communicable diseases (NCDs), the proportion of DAH allocated to NCDs remained low, increasing only from 1% in 1990 to 2% in 2022. Similarly, the overall funding for health system strengthening decreased from 19% in 1990 to 7% in 2022. Major contributors to DAH included the USA, the UK and the Bill & Melinda Gates Foundation. While associations between DAH and improvements in certain health outcomes were observed, establishing causality is challenging due to multiple influencing factors. The COVID-19 pandemic underscored the importance of robust health systems. However, DAH allocation did not show any substantial shift towards health system strengthening during this period. Economic evaluations calculated the median incremental cost-effectiveness ratio of DAH interventions,

Conclusions

This study reviews DAH trends from 1990 to 2022, showing a predominant focus on HIV/AIDS and maternal and child health, with insufficient attention to NCDs and health system strengthening. Despite the increasing burden of NCDs and the impact of COVID-19, DAH priorities have not significantly shifted, highlighting the need for ongoing evaluation and strategic adjustments. To enhance DAH effectiveness, it is crucial to adopt a more balanced approach and also align interventions with needs from recipient countries and implement evidence-based strategies with continuous monitoring and evaluation.

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Development assistance for health (DAH) has played a crucial role in improving health outcomes in low- and middle-income countries. However, there might be a growing mismatch between DAH funding allocations and the shifting global health burden.

• Strengthening health systems and non-communicable diseases (NCDs) are recognised as essential for sustainable health improvements, yet the extent and effectiveness of DAH investment in this area remain inadequately explored over extended periods.

WHAT THIS STUDY ADDS

• NCD funding remains low, increasing from 1% to 2%, while infectious diseases and maternal health dominate.

• The overall DAH allocation for health system strengthening decreased from 19% in 1990 to 7% in 2022.

• DAH is effective for some health outcomes, but overall improvement is limited by multiple factors, requiring continuous evaluation.

• Adjust DAH allocation to increase support for NCDs and health system strengthening, prioritise evidence-based interventions and enhance funding transparency and alignment with recipient needs.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

• Our mix-methods review analysis also shows that DAH has not significantly shifted priorities even in the wake of the COVID-19 pandemic, and our study underscores the need for strategic realignment of DAH funding.

• We suggest using more balanced and evidence-based approaches that aligns with the needs of recipient countries and includes continuous monitoring and evaluation to enhance the effectiveness of DAH interventions.

Introduction

The development assistance for health (DAH) refers to the financial and in-kind resources provided by external donors, such as governments, multilateral organisations and private foundations, to low- and middle-income countries (LMICs) to support health programmes and improve health outcomes.¹,⁴ DAH encompasses funding for various health interventions, including disease-specific programmes, health system strengthening and emergency response efforts.^{5 6} The primary goal of DAH is to supplement the health resources of recipient countries to enhance public health, reduce disease burdens and improve overall health indicators.^{3 7 8} These efforts are realised through international aid projects, partnerships with recipient governments and collaborations with non-governmental organisations.

Over the past decades, DAH has experienced fluctuations. Significant increases were observed in response to global health crises such as the HIV/AIDS epidemic and, more recently, the COVID-19 pandemic.⁹,¹¹ However, outside of these surges, overall DAH has plateaued or even declined in certain areas, raising concerns about the sustainability of health programmes in LMICs that rely heavily on external funding.¹² Previous studies have demonstrated that DAH positively impacts infectious disease control, maternal and child health, and vaccination rates.¹³,¹⁵ However, current research on DAH remains fragmented,^{14 15} often focusing on specific diseases (such as HIV/AIDs, malaria) or regions (such as Sub-Saharan Africa, Middle East and North Africa) and lacking a comprehensive analysis of its overall trends and effectiveness on overall health outcomes. Many studies did not sufficiently examine how both bilateral and multilateral DAH contribute to health system strengthening and resilience. These gaps highlight the need for comprehensive analyses that assess the trends and effectiveness of bilateral and multilateral DAH, particularly regarding its effectiveness in enhancing health systems and improving global health outcomes.

To address these gaps, this mixed-methods review study conducts a comprehensive analysis of bilateral and multilateral DAH trends and effectiveness over the past 30 years, from 1990 to 2022. We aim to provide a holistic view of DAH through a literature systematic review, describing trends in DAH funding allocations and summarising findings from existing studies on the potential associations of DAH with health system and health outcomes.¹⁶ Our objective is to offer valuable insights into the evolution and effectiveness of DAH, thereby informing better strategic planning and implementation of health assistance programmes.

Methods

This article adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and was registered with PROSPERO (CRD42023435151).

Study design

This review study employs a mixed-methods approach, combining quantitative data analysis from existing databases with qualitative analysis from systematic literature review. The quantitative analysis uses newest data (updated to 2022) from the Institute for Health Metrics and Evaluation (IHME) to examine DAH trends over the period of 1990–2022. The systematic review complements qualitative analysis by providing qualitative insights into DAH’s effectiveness and the contexts in which it operates.

Search strategies

The search for relevant literature was performed across several databases: PubMed, Embase, Web of Science and Cochrane, covering a comprehensive span from 1990 to the present. The search covered publications from 1990 to the present, included a comprehensive historical perspective on the topic of DAH. The primary keywords used in the search were “development assistance for health”, “health development assistance”, “aid”, “foreign assistance”, “health system”, “health status” and “health outcomes”. These terms were used in various combinations to maximise the retrieval of relevant articles. For the language, we only considered articles published in English to ensure that the findings could be universally understood and compared. To ensure the quality and reliability of the data collected, we independently conducted searches by two reviewers. We used this dual-review approach to minimise the risk of bias in selecting articles and enhance the comprehensiveness of the literature review.

Each database search was tailored to its specific indexing terms and functionalities. We used advanced search options to filter and narrow down the results based on the inclusion criteria. Regular meetings were held between the reviewers to discuss discrepancies in article selection and refine the search strategies as needed. Furthermore, the references of selected articles were hand-searched to identify additional studies that might have been missed in the initial database search. All search activities, including the search terms used, databases searched, the number of articles retrieved and decisions on article inclusion or exclusion, were meticulously documented.

Inclusion and exclusion criteria

We established inclusion criteria aimed at filtering studies specifically focused on DAH with sufficiently complete results and significance. Specifically, (a) types of research: both qualitative and quantitative studies were considered; (b) research objects were about the DAH or assistance on health status/systems; (c) research designs: included studies could be retrospective, cross-sectional, time-series analyses, randomised controlled trials (RCTs), and non-RCTs; and (d) evaluative focus: studies were required to have a clear evaluation component and report on basic characteristics and main indicators relevant to DAH. Records were also excluded based on several factors: (a) epidemiological monitoring reports; (b) non-English language; (c) lack of a specific evaluation index; (d) work plans and summaries; (e) personal comments; (f) low-quality evaluations (by Ekman’s quality assessment); (g) invalid data literature; (h) yearbooks; (i) newspapers; (j) letters and (k) patents.

Data extraction

After refining the pool to 102 studies deemed eligible, we used the Zotero to manage the full-text articles, ensuring an organised review process. For detailed data entry, two reviewers (SX and SD) independently extracted critical information using a predesigned standardised Excel form, enhancing data integrity and traceability. The form captured essential details, including the title, first author, journal, country and region, and publication year. To resolve any disagreements in the data extracted by the two reviewers (SX and SD), a third reviewer was engaged (SZ), providing an additional layer of scrutiny.

Risk of bias

We ensured the comprehensiveness of our literature search by conducting two thorough retrievals in major literature databases, facilitated by experienced reviewers. This approach minimised publication bias. The extraction of literature data was independently performed by multiple researchers, who cross-verified the results to ensure accuracy and reduce bias in data extraction and entry. Furthermore, multiple researchers independently reviewed the interpretation of results to assess whether they were influenced by the authors’ subjective views or expectations. They also evaluated whether the study authors might be affected by financial support or other potential conflicts of interest, minimising overall bias in the study.

Data integration and analyses

The data for all visualisations were sourced from the IHME official website.¹⁷ We downloaded comprehensive DAH data sets covering the period from 1990 to 2022, including detailed information on financing sources, channels and funding destinations. We used Sankey plots to display the flow of global DAH funding, detailing the finance sources, channels managing the flows and the final destinations of the funds.¹⁸ Additionally, geographical maps were generated to show the distribution of DAH funds from 1990 to 2022. For the source countries, the maps used different colour intensities to represent varying magnitudes of funds provided. Similarly, maps for recipient countries displayed the DAH received, using a colour gradient to signify the amount of funding. We also used stacked plots to show the distribution of DAH funds among various foundation organisations from 1990 to 2022.¹⁹ For all analysis steps, we performed them by using R software V.4.3.2 (R Project for Statistical Computing).

The qualitative component of our analysis involved a meticulous process of data extraction and thematic synthesis based on the six building blocks framework for health systems, as proposed by the WHO: (a) leadership and governance; (b) health workforce; (c) service delivery; (d) medical products; (e) financing and (f) health information.

Based on the definition of DAH, the funding from DAH would potential promote or influence the development in each building block. There would be some association that needs to be evaluated when DAH interacts with the six building blocks framework, especially its role in health system strengthening. The funding from DAH might also functionality and resilience of health systems by targeting specific building blocks. For the relationship between DAH and health outcomes, we focused on key dimensions of health (infectious diseases, maternal and child health, mortality rate and life expectancy).²⁰,²² We initiated this process by extracting relevant information from the literature using the standardised Excel template again. Two reviewers independently reviewed the extracted data to ensure accuracy and consistency. Regular team meetings were held to discuss and resolve any discrepancies in data interpretation or findings. NVivo 11.0 software was used to code and review relevant evidence for the included studies.

Patient and public involvement

The involvement of patients or the public was not applicable to this study. This research was conducted without direct participation from these groups in the design, conduct, reporting, or dissemination phases of the study.

Results

Overview and flow trend

The flowchart in figure 1 outlines the screening and selection process. Initially, a total of 107 514 records were identified. The 10 825 duplicates were removed. We also excluded 95 292 records deemed mismatched to the theme or irrelevant based on their titles and abstracts, primarily filtering out non-relevant content (not aligned with DAH content). We then left 1397 records that matched the thematic focus of our review. The 1397 records underwent eligibility assessments for their article types and content in the main text, based on the inclusion and exclusion criteria. This assessment led to the exclusion of 1295 records, leaving 102 eligible records. Each study was then coded and categorised by research type: (a) retrospective studies (41); (b) cross-sectional studies (25); (c) time-series studies (19); (d) review studies (11); (e) mixed-method studies (4) and (f) RCTs (2). All information on the included articles can be found in online supplemental table 1.

Figure 1. Flowchart for the review study design. Each step represents our records screening strategy and selection process. The flowchart was created with Figma. RCTs. randomised controlled trials.

We analysed the flow of global DAH from 1990 to 2022 using data obtained from the IHME (updated to 2022). The data were divided into three periods: 1990–2000, 2001–2012 and 2013–2022 (figure 2). The other foundations represented the aggregated total of all other foundations, except the Bill & Melinda Gates Foundation (BMGF), while other countries included those not individually listed. The channels section grouped unlisted funding channels under others, and the far-right column grouped unallocated funds or smaller funds for malaria and tuberculosis under other areas. The USA has consistently been the leading contributor, followed by the European Union, the UK and the BMGF.²³,²⁶ The BMGF was a significant non-governmental funder, with its contributions obviously larger than many other foundations. Primary areas of funding support included HIV/AIDS, newborn and child health, and health systems strengthening, followed by reproductive and maternal health, and other infectious diseases. During the 2001–2012, channels like the AsDB saw lower funding volumes and were included under others in the visualisation. The proportion of DAH allocated to non-communicable diseases (NCDs) remained relatively small, increasing only from 1% in 1990 to 2% in 2022. The overall DAH directed towards health system strengthening decreased from 19% in 1990 to 7% in 2022, indicating a shift in donor priorities over time.

Figure 2. Flow of global development assistance for health. For each plot, the left column means the finance sources, the middle column means the channels that manage the flows of funding and the right column means the final actual flow places. BMGF, Bill & Melinda Gates Foundation; NCD, non-communicable disease.

Strategies of major donors (the USA, the UK and BMGF) in DAH: From 1990 to 2000, the USA’s DAH strategies were primarily focused on reproductive and maternal health, which accounted for nearly half of its total funding, followed by investments in HIV/AIDS. However, during the periods of 2001–2012 and 2013–2022, the share of DAH allocated to HIV/AIDS increased significantly, becoming the dominant focus of US health aid. Additionally, the USA emerged as a major contributor to malaria-related support during these years. Similarly, the UK’s DAH strategies between 1990 and 2000 were concentrated on reproductive and maternal health. However, from 2001 to 2022, the UK shifted its focus primarily to newborn and child health, with HIV/AIDS as a secondary priority. BMGF initially (2001–2012) directed substantial DAH towards HIV/AIDS, malaria, newborn and child health, and reproductive and maternal health. In the subsequent period (2013–2022), BMGF shifted its emphasis, prioritising newborn and child health as well as reproductive and maternal health.

DAH distribution over time

This is based on the existing databases (updated to 2022) from the IHME official website. We analysed the geographical distribution and changes in global DAH contributions from 1990 to 2022, detailing contributions across three distinct periods: 1990–2000, 2001–2012 and 2013–2022 (figure 3). Throughout these decades, the USA remained the primary source of DAH, with contributions markedly increasing post-2000, surpassing those of other countries.²⁷,³⁰ Following the USA, the UK emerged as a significant contributor, especially between 2013 and 2022.^{23 31} Other notable contributors included Canada, Australia and China, all channelling substantial funds through bilateral agencies.^{23 32 33} The analysis also highlighted the role of non-governmental foundations, such as the BMGF, in the evolution of DAH funding. We visualised the total contribution funds each year from each non-governmental foundation by stacked plots, comparing through specific amounts. Online supplemental figure 1 presents the contributions from major foundations to DAH from 1990 to 2022. Each label, such as private other, are numbers that are aggregated by many different private organisations. The BMGF was the largest non-governmental funder from 2000 to 2022, significantly influencing funding priorities and strategies in global health. Additionally, we also illustrated the geographical distribution of DAH recipients from 1990 to 2022, along with details for the same three time periods: 1990–2000, 2001–2012 and 2013–2022 (online supplemental figure 2). Geographically, DAH primarily benefited countries in Africa, South America and Asia, with Central and Southern Africa, and South Asia (including India and Pakistan) receiving the most support.³⁴,³⁷ Despite a general upward trend in the scale of assistance, India, Mexico and some South American countries saw a reduction in DAH received during the latest period (2013–2022) compared with earlier years. Such reduction may be attributed to their economic growth and transition to middle-income status, leading donors to shift resources towards lower-income countries with greater needs.

Figure 3. Source/contribution countries geographical distribution of development assistance for health from 1990 to 2022. Different colours represent different magnitudes of funds they provided/donated.

Relationship between DAH and six dimensions of health systems

We analysed how DAH has influenced the six building blocks of health systems defined by the WHO: leadership and governance, health workforce, service delivery, medical products, financing and health information (table 1). DAH has contributed to these dimensions to varying degrees (table 1). For leadership and governance, a portion of DAH (approximately 40%) has been allocated to strengthening governance structures, including the development and implementation of health policies and regulations.^{38 39} Major funding sources included sovereign nations such as the USA, the UK, as well as foundation organisations like the BMGF and the Global Fund.²³ These efforts aim to enhance health system governance in recipient countries, though the extent of their impact varies across different contexts.

Table 1. Association between DAH and six building blocks of health system¹⁶.

Metrics	Observations
Leadership and governance
Primary sources of funding23,26	Sovereignnations: included the US government (through the PEPFAR programme), the UK government (formerly DFID, now FCDO), the Canadian government, the Australian government and the Chinese governmentFoundation organisations: included the Bill & Melinda Gates Foundation and the Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund)
Governance structures and systems38 39	About 40% of the funds were allocated for strengthening governance structures: investments were made in the governance structures of health systems, including regulations, policy development and implementation mechanisms
Policies and strategies	For the COVID-19 pandemic, the distinction in global health security and pandemic preparedness were exposed, particularly in LMICsThere was an increase in DAH funding that strengthened pandemic preparedness capabilities of LMICs
Healthworkforce
Funding investment23 41	Increased significantly from $34 million in 1990 to $1.5 billion in 2016, and a slight decrease in 2019
Geographical distribution	Major donor countries: included the USA, the UK, Canada, Australia and ChinaMain recipient regions: Sub-Saharan Africa, Southeast Asia, East Asia and Oceania
Human resources support41	Funding for health human resources reached $4.1 billion in 2020, marking an increase of 116.5% from 2019
Effect of investment in human resources for health6 42	Personneltraining: training of health personnel accounted for the largest share of human resource-related activities, supporting the short-term skills and capacity enhancement of healthcare workers in LMICsSentinel sites establishment: a significant increase in the construction of sentinel hospitals in LMICsPolicy improvement: the ‘Global Strategy on Human Resources for Health: Workforce 2030’ provides strategic guidance for the long-term development of health human resources
Service delivery
Service accessibility34,37	Investments in healthcare infrastructure in resource-limited regions (Sub-Saharan Africa and Southeast Asia) have improved the accessibility of medical services
Service quality41	In 2020, support for human resources involved in health-related activities reached a historical high of $4.1 billion, enhanced service quality
Remote healthcare services	Expanded coverage and were cost-effective, particularly in the management of chronic diseases and emergency medical services
Global and regional corporations52	Global: broad health service projects were supported through international aid and global health initiatives, such as the Global Fund to Fight AIDS, Tuberculosis and Malaria, and the PEPFARRegional: in specific regions, such as Africa and Southeast Asia, targeted health projects were implemented to address high-burden communicable diseases and to improve maternal and child health
Medicalproducts
Pharmaceuticals	Pharmaceuticals: new medication development: the development of new medications for non-communicable diseases and emerging health threats: Pyramax/Eurartesim (developed by the Medicines for Malaria Venture, approved in 2011)Pricing policies: plans like the Global Fund and PEPFAR support the reduction of medication costs and improve access to medications in low-income countries through centralised purchasing and financial assistance: tenofovir (got cost reductions by bulk purchasing programmes)
Medical devices and equipment	Technology transfer and updates: enhance the overall technological level of the healthcare systems in recipient regions, enabling them to provide more advanced treatments and services: portable ultrasound machines (as part of the Imaging the World initiative have improved maternal health in Uganda through technology transfer)Promotion of equity: DAH can help less-resourced countries or regions gain access to necessary medical equipment, thereby reducing regional disparities in health services and improving equity in healthcare: solar-powered hearing aids developed by Solar Ear (DAH supported the distribution, first launched in Botswana in 2009)
Diagnostic tests13	Disease prevention and control: assist healthcare facilities in middle- and low-income countries to respond swiftly, take appropriate treatment and control measures, and reduce the spread of diseases: malaria rapid diagnostic tests, improved the speed and accuracy of malaria diagnosis in remote areasEconomic benefits: reduced long-term healthcare costs caused by misdiagnosis or missed diagnosis; DAH could promote technology transfer and local production, reducing the dependency of recipient countries on external assistance
Financing
Investment20 23 37	Infrastructure investment: for hospitals and clinics, especially in resource-limited areas, to enhance the accessibility of health servicesHealth technology investment: in medical technology and information technology, including electronic health records, telemedicine services and new diagnostic tools, to improve the quality and efficiency of healthcare servicesDisease investment: in prevention and treatment programmes for specific infectious diseases, typically including drug supply, vaccination, etc.
Medical insurance	Insurance coverage: increasing health insurance coverage in developing countries is a key strategy to improve the accessibility of health services. (eg, some countries in Sub-Saharan Africa have significantly increased insurance coverage through national health insurance plans)Expansion of social protection: efforts by governments and international organisations aimed to extend health insurance to low-income groups and informal sector workers through social security programmes
Financial risk protection52	International funders like the Global Fund and PEPFAR provided financial support to help alleviate the medical burden on individuals and families, ensuring that economically vulnerable groups can access necessary healthcare services
Healthinformation
Electronic health records	Enhanced the efficiency of medical service and patient data management, promoting personalised medicine
Mobile health applications	Allowed users and healthcare providers to track health metrics and symptoms, supported disease prevention and improved self-management
Disease surveillance systems	HIS played a crucial role in infectious disease monitoring and management through real-time data collection and analysis, supporting public health response measures and the implementation of telemedicine services
Clinical decision support systems	Clinical decision support systems integrated into HIS provide physicians with evidence-based treatment recommendations, enhancing the accuracy of clinical decisions

DAHdevelopment assistance for healthHISHealth Information SystemsLMICslow- and middle-income countriesPEPFARUS President’s Emergency Plan for AIDS Relief

The focus of DAH strategies shifted over time.⁴⁰ For the health workforce, investment in the health workforce has increased over the years. DAH allocated to health workforce development grew from $34 million in 1990 to $1.5 billion in 2016.^{23 41} In 2020, during the COVID-19 pandemic, funding surged to $4.1 billion, marking a significant increase (116.5%) from the previous year.⁴¹ This investment supported personnel training programmes and capacity building in LMICs.^{5 42} While these investments are substantial, further research is needed to assess their direct impact on the quality of services. For service delivery, DAH has supported improvements in service delivery by enhancing the accessibility and availability of medical services in underserved regions, such as Sub-Saharan Africa and Southeast Asia. Investments in healthcare infrastructure, including the construction and upgrading of health facilities, have aimed to improve service accessibility. However, establishing a direct causal link between infrastructure investment and improved accessibility requires more detailed analysis.

In terms of medical products, DAH has facilitated access to essential medical products and technologies. For example, initiatives funded by DAH have supported the development of new medications for diseases such as malaria. The Medicines for Malaria Venture developed antimalarial drugs like Pyramax and Eurartesim, approved in 2011. Pricing policies implemented by organisations like the Global Fund and the US President’s Emergency Plan for AIDS Relief (PEPFAR) have helped reduce medication costs and improve access in low-income countries through centralised purchasing and financial assistance. In the financing part, DAH has contributed to health financing by supporting medical infrastructure and health technologies, including electronic health records and telemedicine services. These investments aim to improve the efficiency of health services. Efforts to increase health insurance coverage in developing countries through support for national health insurance plans and social security programmes have also been part of DAH initiatives, potentially enhancing healthcare accessibility and providing financial risk protection. For health information, DAH has supported the development of health information systems, including the enhancement of electronic health records and mobile health applications. These tools play crucial roles in improving patient data management, disease surveillance and clinical decision-making.

Associations between DAH and health outcomes

DAH has been associated with improvements in various health outcomes, particularly in maternal and child health²¹⁴³,⁴⁵ and infectious disease development (table 2). Maternal and child health has received approximately 28.0% of total DAH allocations since 1990,²⁸ and we also reviewed reductions in mortality rates and considerable economic benefits in some LMICs from two analyses.^{46 47} However, establishing a direct causal relationship between DAH and these health outcomes requires a more cautious interpretation due to multiple influencing factors. DAH funding for infectious diseases such as HIV/AIDS, malaria and tuberculosis has increased in certain degree over the years, with also some fluctuations.^{2034 48},⁵³ For instance, DAH funding for HIV/AIDS rose to 26% of total DAH by 2015; funding for malaria increased to 6.4%; and for tuberculosis increased to 3.5%, showing large increases, although the proportion was still relatively small. But the relative proportion of DAH funding for maternal and child health decreased to 29% in 2015 compared with 35% in 1990.⁵⁴ Between 2000 and 2010, development assistance for HIV/AIDS increased at an annualised rate of 22.8%, although growth slowed after 2010; and also malaria got 96% external contribution by the Global Fund for malaria in 2013, while it did not follow the rising national GDP rates, causing potential gaps in service delivery needed at that time.^{28 52} Moreover, studies have reviewed associations between DAH and improvements in life expectancy. One analysis reported that a 1% increase in health aid was associated with a 0.24-month increase in life expectancy (95% CI: 0.02 to 0.46; p=0.03).⁵⁵ Additionally, the age-adjusted adult mortality rate in focus countries was 8.3 per 1000 adults (95% CI: 8.0 to 8.6) compared with 8.5 in non-focus countries (95% CI: 8.3 to 8.7).³⁴

Table 2. Association between DAH investments and health outcomes.

Metrics	Observations
Distribution
Major donors and organisations27,30	The US government is the largest source of DAH, providing $143 billion from 1990 to 2014 Other donors include the Bill & Melinda Gates Foundation and the Global Fund to Fight AIDS, Tuberculosis and Malaria
Main health areas2034 48,54	The significant part of DAH has been allocated to infectious diseases (HIV/AIDS, malaria, and tuberculosis) and maternal and child health In 2015, funding for HIV/AIDS rose to 26% of the total, with significant increases in funding for malaria and tuberculosis as well
Influence of geopolitical and economic factors	China and India’s health assistance projects in Africa and Asia were increased over time, demonstrating the rising influence of emerging economies in the global health sector The UAE, Saudi Arabia and Kuwait made significant contributions to DAH in the Middle East and North Africa region in 2017, totalling $548 million
Achievements
DAHachievements
Maternal and child health2143,45	28.0% of all DAH has been allocated to maternal health as well as newborn and child health since 1990 The estimated benefits of maternal and child health programmes, in terms of monetary gains from reduced maternal mortality and under-5 mortality, are $681 416, $4 332 376 and $1 710 184, respectively
Infectious diseases2848,53	HIV/AIDS: the DAH increased from 4.4% in 1990 to 26% in 2015 Between 2000 and 2010, development assistance for HIV/AIDS increased at an annualised rate of 22.8%, although growth slowed after 2010 From 2000 to 2015, DAH for HIV/AIDS increased to $52.6 billion
	Tuberculosis: increased from 0.4% in 1990 to 3.5% in 2015 The global incidence of tuberculosis was slowly declining, and mortality was decreasing with the introduction of more effective diagnosis and treatment
	Malaria: the Global Fund was the largest external funding for malaria, providing 96% of external funds in 2013
Mortality rate34	The age-adjusted adult mortality rate in focus countries is 8.3 per 1000 adults (95% CI: 8.0 to 8.6) The mortality rate in non-focus countries is 8.5 per 1000 adults (95% CI: 8.3 to 8.7)
Life expectancy55
	Every 1% increase in health aid is associated with an increase in life expectancy of 0.24 months (95% CI: 0.02 to 0.46; p=0.03) The link between health assistance and health improvements was strongest between 2000 and 2010, with health improvements related to health aid measurable within 3–5 years after assistance disbursement
Cost-effectiveness of health interventions
Infectious diseases12	HIV/AIDS: the median incremental cost-effectiveness ratio per disability-adjusted life-year averted, life-year obtained, or quality-adjusted life-year increased was estimated at $48.9 (IQR, 9.2–206.5) for HIV/AIDS
	Tuberculosis: $8.2 (IQR, 2.3–21.0) for tuberculosis
	Malaria: $9.7 (IQR, 1.9–37.0) for malaria
NCDs12	$187.4 (IQR, 35.4–739.6) for NCDs
	Maternal and childhealth: $67.7 (IQR, 19.0–240.0) for maternal and child health interventions

There was no significant correlation between the daily direct death number from tuberculosis and the reduction in tuberculosis mortality, indicating that despite assistance, the impact on reducing tuberculosis mortality was limited.

DAHdevelopment assistance for healthNCDsnon-communicable diseases

Health economic evaluations of DAH

Previous economic evaluations have demonstrated that DAH interventions can be cost-effective. For example, the median incremental cost-effectiveness ratio per disability-adjusted life-year (DALY) averted, life-year obtained or quality-adjusted life-year increased was estimated at $48.9 (IQR, 9.2–206.5) for HIV/AIDS, $8.2 (IQR, 2.3–21.0) for tuberculosis and $9.7 (IQR, 1.9–37.0) for malaria. In contrast, the cost per DALY averted was higher for NCDs, with $187.4 (IQR, 35.4–739.6) for NCDs and $67.7 (IQR, 19.0–240.0) for maternal and child health interventions.¹² These differences suggest that overall DAH investments in infectious diseases may still offer greater cost-effectiveness compared with NCDs, although some NCDs are increasingly contributing to the global disease burden. Additionally, this review also revealed the influence of geopolitical and economic factors on health assistance, particularly the investments from emerging economies such as China and India, indicating a shift in the geopolitical landscape of global health assistance.

Discussion

Our study provides a comprehensive analysis of DAH from 1990 to 2022, revealing trends in funding sources, channels and focus areas. The USA has remained the largest contributor throughout the three decades, with significant contributions also from the UK, Canada and emerging donors like China. Non-governmental organisations and foundations, particularly the BMGF, have played increasingly important roles in DAH funding. More DAH strategies are focusing on developing health infrastructure in historically underfunded regions such as Africa and South America.^{2023 37 56},⁵⁹ Our analysis shows that DAH has predominantly focused on infectious diseases and maternal and child health. For instance, maternal and child health received approximately 28.0% of total DAH allocations, while DAH for HIV/AIDS rose to 26% of total DAH by 2015.^{29 54} Despite the growing global burden of NCDs, the proportion of DAH allocated to NCDs remains relatively small, increasing only from 1% in 1990 to 2% in 2022. Similarly, the overall funding for health system strengthening decreased from 19% in 1990 to 7% in 2022. This indicates that contrary to some expectations there has not been a significant shift in DAH focus towards NCDs or health system strengthening over the study period. However, this number may underestimate the true extent of support for health systems strengthening within disease-specific areas. For instance, 38% of HIV/AIDS and 37% of malaria DAH funding supported health system strengthening activities.^{60 61} These figures illustrate that a certain portion of some disease-specific DAH contributes to strengthening health systems. It highlights the contribution difference in different disease-specific funding for health system infrastructure. But more health system support in various disease-specific areas still needs further details.

We have observed significant shifts in the DAH strategies of the USA, the UK and the BMGF over different periods. These changes reflect the donors’ ability to adjust their funding strategies in response to global health needs and policy frameworks. For instance, after 2001, the USA substantially increased its funding for HIV/AIDS, demonstrating an urgent response to the global AIDS epidemic. Similarly, post-2001, the UK shifted its focus towards newborn and child health, aligning with the Millennium Development Goals and Sustainable Development Goals aimed at reducing child mortality rates. BMGF’s strategic adjustments also indicate adaptability to global health challenges. These trends offer valuable insights for other donors, emphasising the importance of dynamically aligning funding strategies with evolving global health needs.⁶² Future research could further explore the driving factors behind these strategic shifts, such as global policy frameworks, emerging health challenges and geopolitical influences, to provide a more comprehensive understanding.

The COVID-19 pandemic has underscored the importance of robust health systems and global health security.⁹,¹¹ While some opinions might anticipate an increase in DAH allocated to health system strengthening during the pandemic, our data do not show a substantial increase in the proportion of DAH directed towards this area. Instead, funding continued to be channelled primarily towards infectious disease control and maternal and child health.¹³,¹⁵ This could be due to the immediate need to respond to the pandemic, which is itself an infectious disease, requiring significant resources for prevention, diagnosis and treatment.⁴¹ Our findings highlight the complexity of DAH allocation and the challenges in aligning aid with evolving global health priorities. While DAH has been associated with improvements in certain health outcomes, such as reductions in mortality rates for specific diseases, it is difficult to establish causality due to the multifaceted nature of health determinants and the presence of other influencing factors like domestic health spending and policy changes.³¹ Additionally, the effectiveness of DAH varies, and aid may not always lead to positive health outcomes, unintended negative effects and inefficiencies can occur instead.^{13 63}

Our findings suggest that the association between DAH and the six health system building blocks stems from the strategic allocation of DAH funds to initiatives that directly strengthen these components. DAH is not solely about funding specific health programmes; it operates through mechanisms that enhance the foundational elements of health systems. For instance, DAH can influence leadership and governance by providing financial and technical support for the development of health policies and regulatory frameworks.^{38 39} In terms of the health workforce, DAH funds can be channelled into training programmes, addressing workforce shortages and enhancing the skills of healthcare professionals, which directly impacts service quality and delivery.^{23 41} Regarding service delivery, DAH can invest in healthcare infrastructure and the expansion of services in underserved areas, improving accessibility and efficiency of care.^{5 42} For medical products, DAH can facilitate research, development and distribution of essential medicines and technologies, ensuring that health systems have the necessary tools to meet population health needs, etc.⁶⁰ These potential mechanisms demonstrate that DAH is linked to the health system building blocks by intentionally directing resources to fortify each component. Recognising these associations is vital for aligning DAH with health system needs, ensuring that aid not only addresses immediate health concerns but also contributes to sustainable health system strengthening.

We also suggest that future research should focus on evaluating the effectiveness of DAH interventions, identifying best practices and understanding the factors that enhance or hinder the impact of DAH on health outcomes.⁵⁵ Also, the DAH can increasingly focus on integrated health strategies that address the interconnected domains of human, animal and environmental health, ensuring that funding covers these linked areas. Enhancing the capacity for disease prevention, control and treatment is essential, not only improving capabilities in the human health sector but also controlling diseases related to animal health and environmental transmission. The health needs of vulnerable populations should be particularly addressed, ensuring equitable distribution of funds and resources.^{5 42} The funding sources can be diversified, including the responsibility of developed countries and assistance from emerging developing countries.^{23 29} Developed countries should continue to play a major funding role to ensure sufficient resources for the global health sector.

At the same time, citizen society participation should be strengthened, continuously encouraging investments from non-governmental organisations and the private sector.² We also suggest developing countries to gradually increase self-assistance to reduce reliance on external aid, establishing more autonomous and sustainable health systems. These findings also suggest that DAH strategies should focus more on health systems strengthening, improving health equity and protecting vulnerable populations. By adapting to global health changes and fostering sustainable development, DAH can effectively address potential health crises and promote universal health coverage. This study provides a foundation for further research, practice and policy development, emphasising the importance of adaptive strategies and collaborative efforts in enhancing global health outcomes.

Limitations

This review study has several limitations. First, the data used for analysis are primarily descriptive, and it is difficult to establish causal relationships between DAH and health outcomes. Second, our data analysis highly relies on data from the IHME (updated to 2022), which may be subject to any potential reporting biases or inaccuracies. Third, the inclusion of only English-language publications in our review introduces the potential for language bias and may have led to the exclusion of relevant studies published in other languages. Expanding future reviews to include non-English publications would provide a more comprehensive understanding of DAH’s global impact. Fourth, the heterogeneity of the included studies and data sources may affect the generalisability of our findings. Furthermore, the proportion of DAH included in health systems strengthening for more specific diseases is still not enough clear, and there may be more differences with overall health systems strengthening. More detailed information is needed in the future. Critical future directions will be using ongoing monitoring, more detailed data collection and data analysis methods like subgroup and sensitivity analysis to address these sources of heterogeneity.

Conclusion

This review study provides a comprehensive overview of the evolution and impact of DAH trends from 1990 to 2022, highlighting that DAH has primarily focused on HIV/AIDS and maternal and child health, with relatively limited allocation to NCDs and a decrease in the proportion directed towards health system strengthening. Despite the increasing global burden of NCDs, DAH allocation has not significantly shifted towards these diseases. The COVID-19 pandemic has emphasised the need for robust health systems. However, the findings suggest that DAH has not substantially increased its focus on health system strengthening. These results underscore the necessity for ongoing assessment of DAH priorities and effectiveness. Future DAH strategies should consider more balanced approaches and ensure aid effectiveness. It is important to recognise that DAH is not always effective and can have unintended negative effects on health outcomes. Therefore, efforts should be made to enhance the impact of DAH through evidence-based interventions, alignment with needs from recipient countries and continuous monitoring and evaluation.

Data availability statement

Data are available in a public, open access repository.