Hypertension and diabetes are two of the high prevalent non-communicable diseases (NCDs) that have emerged as a global public health crisis (1). It’s estimated that 1 billion and 422 million people are living with hypertension and diabetes worldwide, respectively, and this figure is expected to rise greatly over the coming decades (2, 3). Hypertension is a common co-morbidity in people with type 2 diabetes, with 74% having coexisting high blood pressure (4). Patients with hypertension and diabetes often have complex clinical course and multifaceted care needs and are in great need of long-term and a wide range of health care services that are well-integrated and person-centred (5, 6). However, insufficient care coordination among health systems and between health professionals from different disciplines are widely recognized (7, 8). Patients with hypertension and diabetes often experience duplicated, fragmented and uncoordinated care, which inevitably contributes to suboptimal treatment, frequent hospitalization and enormous burden on health systems (9, 10).
In order to respond to the challenges associated with chronic diseases and address the complexities of managing multi-morbidities, efforts have been made globally to promote better-integrated care through strengthening the coordination and cooperation among health systems, health professionals, patients and their caregivers (11, 12). Person-centred integrated care has been proposed by the World Health Organization as a global strategy to improve health outcomes, enhance quality of patient care and reduce high-cost hospitalization for populations (13).
Integrated care interventions are often multifactorial and complex, which can take place across multiple levels. These are the macro level of health systems that enhance collaboration between health organizations, the meso level of health professionals that facilitates multi-disciplinary team in delivery of care services, and the micro level of individuals that promotes multi-component self-care (14, 15). Despite the importance of implementing multi-level and multi-component interventions, actual practices are often limited across these three levels leading to suboptimal integration of health services, poor health outcomes and unsatisfactory patient experiences (13, 16). A factor limiting the implementation of integrated care is the lack of a taxonomy of the necessary elements that reflects its inherent multi-level and multi-component nature (16). Therefore, transforming towards integrated care requires a comprehensive understanding of the requisite elements and mechanism of this care approcah, which calls for a systematic review.
Varied and inconsistent definitions of integrated care (8, 17) and failure to recognise the inherent natures of these elements have led to mixed results and difficulties in developing and scaling up integrated care (18). The heterogeneous nature of integrated care intervention components resulting from conceptual ambiguity hinders meta-analysis for pooled effect size and poses challenges to the replicability and reliability of studies (10, 19). A systematic review by Baxter et al. (2018) evaluated the efficiency of integrated care on service delivery in terms of access to care and quality of care (19). The lack of a precise pre-specified definition of integrated care and disease-defined patient group precluded meta-analysis of clinical outcomes. Similarly, systemetic reviews by Liljas et al. (2019) and Martínez-González et al. (2014) identifing the elements of effective integrated care in improving health outcomes (8, 20) solely examined the organization (macro) level and did not take into account the scale of the interventions at micro and meso levels. Hence, to understand the highly complex nature of integrated care, existing research needs to be examined using a clear classification of the components supported by a specific theoretic framework.
To enable comparison of the studies included in the review, we have used the definition of integrated care as proposed by the World Health Organisation and by Rainbow Model for Integrated Care.
“Integrated care is an approach to strengthen people-centred health systems through the promotion of the comprehensive delivery of quality services across the life-course, designed according to the multidimensional needs of the population and the individual and delivered by a coordinated multidisciplinary team of providers working across settings and levels of care” (13).
The Rainbow Model for Integrated Care has emphasized that effective and well-developed person-centred integrated care should be based on multi-level multiple-component care integration that includes well-organised health systems, individually-tailed patient support and close engagement of health professionals (21).
The scope of integrated care varies across high- income countries (HICS) to low- and- middle- income countries (LMICs). Given considerable context-specific variations of integration mechanisms in integrated care, it is important to evaluate integrated care in a specific context and populations. To reduce the impacts from clinical heterogeneity in terms of population and settings, our study only focuses on the review of integrated care in high-income countries.
To our knowledge, only two systematic reviews have examined integrated care for diabetes pertaining to intervention types and outcomes (22, 23). The review by Busetto et al. (2016) was restricted to only two databases, which possibly led to a large number of relevant studies being overlooked and therefore the summarised evidence inconclusive (22). The other review by Lim et al. (2018) only included integrated care interventions that lasted at least 12 months, which may lead to a high risk of search bias (23). The definitive impact of disease-specific integrated care for both hypertension and diabetes remains unclear. This review addresses the knowledge gap in the literatures.
To date, research evidence is lacking on how to best design, organize and deliver integrated care for people with hypertension and diabetes and the extent to which full care integration (the combinations of all three levels of care integration) improves health outcomes compared with partial care integration. Given the variability in terms of intervention ingredients, duration, delivery process and disease type, there is a need to undertake a systematic review to explore the components and effectiveness of interventional studies to improve person-centred of integrated care for people with hypertension and diabetes in high-income countries.
Aims
The primary aim of this review is to systematically evaluate the effectiveness of person-centred integrated care interventions for people with coexisting hypertension and diabetes. We also aim to identify the key characteristics, core components and delivery methods of effective integrated care strategies through analysis of integrated care across macro, meso and micro levels. The PICO (Population, Intervention, Comparison, Outcomes and Study designs) framework of the Cochrane review will formulate eligibility criteria of studies and ensure search quality (24).