Implementation strategies, outcomes and determinants of integrated care for cardiometabolic conditions and mental, neurological and substance use disorders: protocol for a mixed-methods systematic review

Abstract

Abstract Ιntroduction The co-occurrence of cardiometabolic diseases and mental, neurological and substance use disorders health conditions represents a growing global health burden, particularly in low- and middle-income countries. Although integrated, people-centred multimorbidity care is increasingly recognised as essential across settings, evidence remained limited on how these models are operationalised in routine practice and which implementation strategies are most effective to support their delivery. This protocol outlines the methods for a systematic review aiming to identify implementation strategies used to integrate care for cardiometabolic conditions and mental, neurological and substance use (MNS) disorders, examine associated implementation outcomes and explore contextual determinants influencing implementation across settings. Methods and analysis This protocol follows the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) guidelines. A comprehensive search will be conducted in PubMed, CINAHL, APA PsycINFO, Scopus and Web of Science and relevant grey literature sources. Eligible studies include randomised controlled trials, quasi-experimental studies, mixed-methods studies, qualitative studies and implementation evaluations reporting on integrated care models addressing both cardiometabolic conditions and MNS disorders. To be included in this Systematic Review, studies must detail strategies or models integrating care for at least one cardiometabolic condition and one MNS disorder and provide data on implementation outcomes or contextual determinants. Title/abstract screening, full-text screening, data extraction and data synthesis will be conducted independently by at least two researchers following pilot testing. A formal risk of bias assessment will be performed using the Mixed Methods Appraisal Tool. A mixed-method, framework-based synthesis will be undertaken. Implementation strategies will be coded using the Expert Recommendations for Implementing Change taxonomy, implementation outcomes using Proctor et al’s taxonomy, and contextual determinants using the Consolidated Framework for Implementation Research. Quantitative data will be summarised descriptively using frequencies, proportions and summary tables, with findings stratified by country income level, setting and type of integrated care model where possible. Qualitative data will be analysed using inductive coding and deductive mapping to implementation science frameworks. Ethics and dissemination Ethical approval is not required as no primary data will be collected. The findings of this study will be disseminated through peer-reviewed publications, conference presentations, and stakeholders’ engagement in the field. Registration details The protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 6 April 2026 (registration number CRD420261321825).