National adaptation and implementation of WHO Model List of Essential Medicines: A qualitative evidence synthesis

Background
The World Health Organization Model List of Essential Medicines (WHO EML) has played a critical role in guiding the country-level selection and financing of medicines for more than 4 decades. It continues to be a relevant evidence-based policy that can support universal health coverage (UHC) and access to essential medicines. The objective of this review was to identify factors affecting adaptation and implementation of WHO EML at the national level.

Methods and findings
We conducted a qualitative evidence synthesis by searching 10 databases (including CINAHL, Embase, Ovid MEDLINE, Scopus, and Web of Science) through October 2021. Primary qualitative studies focused on country-level implementation of WHO EML were included. The qualitative findings were populated in the Supporting the Use of Research Evidence (SURE) framework, and key themes were identified through an iterative process. We appraised the papers using the Critical Appraisal Skills Programme (CASP) tool and assessed our confidence in the findings using the Grading of Recommendations Assessment, Development and Evaluation working group-Confidence in Evidence from Reviews of Qualitative research (GRADE-CERQual). We screened 1,567 unique citations, reviewed 183 full texts, and included 23 studies, from 30 settings. Non-English studies and experiences and perceptions of stakeholders published in gray literature were not collected.

Our findings centered around 3 main ideas pertaining to national adaptation and implementation of WHO EML: (1) the importance of designing institutions, governance, and leadership for national medicines lists (NMLs), particularly the consideration of transparency, coordination capacity, legislative mechanisms, managing regional differences, and clinical guidance; (2) the capacity to manage evidence to inform NML updates, including processes for contextualizing global evidence, utilizing local data and expert knowledge, and assessing budget impact, to which locally relevant cost-effectiveness information plays an important role; and (3) the influence of NML on purchasing and prescribing by altering provider incentives, through linkages to systems for financing and procurement and donor influence.

Conclusions
This qualitative evidence synthesis underscores the complexity and interdependencies inherent to implementation of WHO EML. To maximize the value of NMLs, greater investments should be made in processes and institutions that are needed to support various stages of the implementation pathway from global norms to adjusting prescribed behavior. Moreover, further research on linkages between NMLs, procurement, and the availability of medicines will provide additional insight into optimal NML implementation.

Protocol registry
PROSPERO CRD42018104112