Non-communicable diseases (NCDs) pose a significant global health challenge, accounting for a majority of deaths worldwide in 2019. LMICs bear the brunt of this burden, experiencing over three-quarters of global NCD deaths and 85% of premature NCD deaths. This high mortality rate hinders progress towards achieving the Sustainable Development Goals (SDGs), particularly SDG 3.4, which aims to reduce premature deaths from NCDs by one-third. The multisectoral nature of NCD risk factors necessitates an 'all-of-society' approach, including the private sector. International organizations like the WHO and the UN have advocated for multi-stakeholder engagement, emphasizing the private sector's potential role in addressing NCDs. The private sector is increasingly recognized as a provider of healthcare services and products, a source of funding and investment, a contributor to workforce training, and a facilitator of infrastructure development. However, a critical gap exists in the evidence and guidance concerning the for-profit private sector's role in NCD prevention and management in LMICs. To address this deficiency, the authors developed an a priori framework outlining six pillars of private sector involvement in NCD prevention and management, and this study conducted six corresponding systematic reviews to assess the private sector's actions within these roles, specifically within an LMIC context.

The study notes a lack of evidence and guidance regarding the role of the for-profit private sector in NCD prevention and management, particularly in LMICs. The authors reference previous work emphasizing the private sector's potential contributions to healthcare, including innovation, service provision, funding, and infrastructure support. This study aims to fill the evidence gap by systematically reviewing the private sector's involvement across six key pillars: public-private partnerships (PPPs), governance and policy, healthcare provision, innovation, knowledge education, and investment and finance. The literature review likely informed the selection of these pillars and the research questions guiding each systematic review.

This study employed a series of six systematic reviews, each focusing on one of the six pillars of the a priori framework. The reviews followed the PRISMA guidelines, although no formal protocol was prepared. A comprehensive search strategy was implemented across six databases (Embase, PubMed, Web of Science, Cochrane Library, ProQuest ABI/Inform, and Business Source Premier) and the websites of numerous relevant organizations (WHO, World Bank, UNICEF, OECD, American Cancer Society, NCD Alliance, UICC, CSIS, World Economic Forum, CDC, Harvard School of Public Health, USAID, Medtronic, AstraZeneca, Novo Nordisk, Rabin Martin, C3, and Merck). The search focused on studies published in English since 2000 involving the relevant pillar, the for-profit private sector, NCD prevention/management, and an LMIC context. Study selection involved multiple stages of screening using Covidence software, with one reviewer per review handling the process. Data extraction was performed using a piloted data extraction form, also managed by one reviewer per review. Quality assessment of included studies was conducted using the tool developed by Hawker et al., assessing nine quality areas and assigning letter grades based on total scores. Data synthesis utilized an inductive thematic synthesis approach to identify overarching themes from the extracted data. The authors acknowledge the absence of patient and public involvement in the study design and conduct.

The six systematic reviews yielded a total of 182 studies (ranging from 15 to 42 studies per review). Key findings revealed diverse roles for the for-profit private sector in NCD prevention and management in LMICs, categorized by the framework's six pillars: **Public-Private Partnerships (PPPs):** PPPs demonstrated coordination of public and private efforts, mobilization of financial resources, provision of healthcare services and medications, health promotion activities, capacity building through training, and influence on policy. However, examples of PPPs involving science, technology, and innovation (STI) research were limited. **Governance and Policy:** The private sector actively engaged in lobbying (including litigation and influence peddling), shaping public perception, and influencing the regulatory environment. Self-regulation was found to be insufficient, and industry efforts often prioritized business interests over public health goals. **Healthcare Provision:** The private sector played a significant role in providing NCDs diagnoses and treatments, infrastructure (hospitals, labs, pharmacies), and improving availability and accessibility of services. However, affordability remained a significant concern, with private sector care often more expensive. Patients faced high out-of-pocket expenses leading to many forgoing recommended treatment. **Innovation:** The private sector contributed to product, process, and marketing innovation. However, the potential for bias in industry-funded research is noted. **Knowledge Education:** The private sector offered training for healthcare professionals, conducted health promotion campaigns, and helped to shape industry standards and guidelines. The authors note that improved health awareness alone does not automatically lead to better health outcomes. **Investment and Finance:** Private sector involvement in financing NCD control and management was multifaceted. It included both positive aspects (subsidization, direct investment, collaborative financing, innovative financing) and negative ones (high treatment costs, out-of-pocket expenses, and supply chain markups). The high costs of originator drugs were identified as a major barrier to affordability. The authors note that while some positive roles of the private sector may be more numerous than negative, they must be accompanied by proper regulatory frameworks.

The findings highlight the complex and often contradictory roles of the for-profit private sector in NCD prevention and management in LMICs. While the private sector offers potential benefits in terms of resources, expertise, and innovation, it also presents significant challenges related to conflicts of interest (COIs). These COIs manifest through lobbying activities that may impede effective policy implementation, the potential for bias in industry-funded research, and the prioritization of commercial interests over public health goals. The substantial out-of-pocket expenses associated with private healthcare services also exacerbate health inequalities. The study emphasizes the need for policies that encourage private sector participation in areas that align with public health goals while establishing robust regulatory frameworks to mitigate COIs. The authors argue that a balance must be struck to leverage the private sector's potential contributions while protecting against its potential negative impacts.

This study provides a comprehensive overview of the for-profit private sector's involvement in NCD prevention and management in LMICs, filling a gap in the existing literature. The findings highlight the complex interplay of benefits and risks associated with private sector engagement, emphasizing the need for carefully designed policies that promote collaboration while safeguarding against COIs. Future research should focus on evaluating the effectiveness of different regulatory strategies in mitigating COIs and maximizing the positive contributions of the private sector in improving NCD outcomes in LMICs. Further research should explore how to develop more effective PPPs that incorporate STI innovations.

The study acknowledges several limitations. First, single-reviewer screening, data extraction, and quality assessment could introduce bias, though efforts were made to mitigate this with clear guidelines and inclusion/exclusion criteria. The limitation of including only English-language studies might have excluded relevant research. Many included studies were of low quality, possibly due to the nature of the studies themselves and the lack of formal methods sections. These limitations should be considered when interpreting the results.