EVALUATING THE WHO PEN INITIATIVE: A SYSTEMATIC REVIEW OF ITS INFLUENCE ON NON-COMMUNICABLE DISEASE AWARENESS AND PREVENTION AMONG PRIMARY HEALTHCARE WORKERS IN NIGERIA

Background: Non-communicable diseases (NCDs) are a leading cause of morbidity and premature mortality globally, with disproportionate burden in low- and middle-income countries. In Nigeria, primary health care workers (PHCWs) play a critical frontline role in combating the epidemic. The World Health Organization Package of Essential Non-Communicable Disease Interventions (WHO PEN) was developed to strengthen NCD prevention and management within primary healthcare (PHC) systems; however, its overall impact on provider knowledge and preventive practices in Nigeria remains fragmented and poorly synthesized Objective: To systematically review empirical evidence on the impact of WHO PEN interventions on PHCWs’ knowledge and preventive practices related to non-communicable diseases in Nigeria. Methods: This systematic review was conducted in alignment with the PRISMA 2020 guidelines. A comprehensive literature search was undertaken across five databases: PubMed, Scopus, Web of Science, African Journals Online (AJOL), and Google Scholar, for studies published between 2010 and 2024. Eligible studies included quantitative, qualitative, and mixed-methods designs that evaluated the WHO PEN implementation outcomes among PHCWs in Nigerian settings. Of the 1,165 records identified, 978 were screened after removing duplicates, and 34 studies met the inclusion criteria. Data were extracted and synthesized thematically across two core outcome domains: NCD knowledge and preventive practices. Results: Twenty-eight of the 34 studies reported measurable improvements in PHCWs’ knowledge following PEN implementation, particularly in hypertension screening (n = 22), diabetes risk assessment (n = 18), and behavioral risk counseling (n = 15). Nineteen studies also documented enhanced preventive practices, including increased routine screening, lifestyle education, and referral accuracy. Positive outcomes were most pronounced in states with consistent training, supervision, and policy support. However, infrastructural constraints, workforce shortages and weak follow-up mechanisms limit sustainability, especially in rural and conflict-affected regions. Regional disparities highlight the need for decentralized adaptation of PEN strategies. Conclusion: The WHO PEN interventions are effective in improving NCD-related knowledge and preventive practices among Nigerian PHCWs, particularly when implemented with structured training, system support, and infrastructure. Nonetheless, contextual barriers—such as inadequate diagnostic resources, poor referral networks, and governance limitations—undermine long-term impact of such barriers.. To optimize PEN’s effectiveness, integrated strategies that prioritize PHCW training, health system strengthening, and region-specific adaptation are essential