To assess the evidence for health system level barriers or facilitators to hypertension detection, treatment or control.
MEDLINE, EMBASE, and Global Health will be searched using a combination of free text and subject heading terms relating to:
2. A variety of health systems components.
No date or language restrictions will be applied.
Types of study to be included
Any quantitative or qualitative study design.
Condition or domain being studied
Around a billion people worldwide have hypertension, nearly three-quarters of whom live in developing countries. In both developed and developing countries a significant proportion of people with hypertension remain undetected, and of those with their hypertension detected, only a minority have their hypertension successfully controlled. Hypertension remains one of the most important modifiable risk factors for cardiovascular disease, including coronary heart disease and stroke. Improving rates of hypertension detection, treatment and control is, therefore, vital if we are to reduce mortality rates from cardiovascular disease in both developed and developing countries.
Any population at the community, primary, secondary or tertiary care level will be included.
We will include studies that evaluate health system barriers or facilitators to hypertension detection, treatment or control operating at the macro or meso level of the health system.
The macro level of the health system includes, for example, national and international policies, national funding structures and national health care delivery structures.
The meso level of the health system includes, for example, regional health systems as well as organisations such as hospitals or primary care organisations.
Studies that only examine the effect of individual level (micro) barriers and facilitatiors to hypertension detection, treatment or control will not be included.
We will not exclude or include studies based on the presence of a control or comparator group.
In order to implement strategies to improve hypertension detection, treatment and control a comprehensive understanding of the barriers and facilitators to optimal hypertension care is required. Detection, treatment or control of hypertension may be affected by barriers or facilitators at the macro, meso or micro levels of the health system. The macro level of the health system includes national and international health systems, the meso level incorporates local health systems and organisational structures such as hospitals and primary care organisations and the micro level involves the individuals that are integral to the health system including patients and healthcare practitioners. Barriers and facilitators to optimal hypertension care at the micro level of the health system may, for example, relate to knowledge and awareness of hypertension amongst patients and health care practitioners or to financial factors. Barriers and facilitators to optimal hypertension care at the macro and meso health system levels might, for example, relate to strategies for procurement of essential medications, the existence of simple national guidelines for hypertension care, or the lack or presence of financial incentives for healthcare practitioners to diagnose or treat hypertension.A number of studies have attempted to assess barriers or facilitators to hypertension detection, treatment or control, both qualitatively and quantitatively. (Howes et al., 2010, Mendis et al., 2004, Ahluwalia et al., 1997, Wexler et al., 2009, Cornwell and Waite, 2012). However, there is no systematic review of the results or an appraisal of the quality of these studies. An overview of these studies could clarify the relative importance of identified barriers and facilitators to optimal hypertension care and examine geographical differences in these factors. Such an overview could also identify areas of health systems research that lack evidence, so that specific targets can be prioritized for future research on barriers and interventions for improvement of hypertension control.
This review focuses on the higher levels of the health system (macro and meso), evaluating barriers and facilitators for hypertension detection, treatment or control.
To conduct this systematic review we have adopted a conceptual framework for health system management of chronic diseases. This conceptual framework facilitates the conduct and reporting of the systematic review, and can also help identify gaps in the literature, by indicating areas that require further research.
Several frameworks have been proposed to understand the functions of a health system. (Atun et al., 2010, WHO, 2007, Hsiao, 2003). This review adopts a health systems framework that we previously used to assess the heath systems preconditions for assessing diabetes care in the former Soviet Union (Balabanova et al., 2009, Hopkinson et al., 2004). This framework recognises that in order for a health system to respond effectively to the growing burden of chronic disease certain inputs need to be in place: namely physical resources, human resources, intellectual resources and social resources. However, the framework goes beyond the enumeration of supply-side inputs, recognising that even if many of these are present, treatment and control of hypertension can be at suboptimal levels. The framework, therefore, acknowledges the importance to health systems of funding and organisational and governance structures in contributing to health outcomes.
Hypertension detection, treatment or control.
We define hypertension detection as the presence of a reported diagnosis of hypertension by a healthcare professional; hypertension treatment as the use of at least one antihypertensive drug in diagnosed hypertensives; and hypertension control as the presence of blood pressure below a target threshold such as 140/90 mmHg in treated hypertensives.
Adherence to anti-hypertensive medication.
Data extraction, (selection and coding)
Two reviewers will independently extract data from included studies using standardised forms. We developed forms for extracting data on study characteristics and results for both quantitative and qualitative studies. These forms will be piloted by the reviewers on two randomly selected included studies and edited based on feedback received.
Risk of bias (quality) assessment
Quality appraisal of quantitative studies:
We will assess the quality of the included quantitative studies as recommended by GRADE (Grading of Recommendations, Assessment, Development, and Evaluation). GRADE is a systematic approach of rating quality of evidence on five specific domains:
1) Study limitations, 2) Inconsistency of results, 3) Indirectness of the evidence, 4) Imprecision, and 5) Publication bias.
Quality appraisal of qualitative studies;
Qualitative studies will be evaluated using an adapted version of a checklist used in a previous series of mixed methods systematic reviews incorporating both quantitative and qualitative studies (Rees et al., 2001, Harden et al., 2001).
Strategy for data synthesis
Qualitative and quantitative studies results will be presented separately.
Where possible we will report dichotomous outcomes as relative risks (RR) and continuous data as mean differences (MD) (with 95% confidence intervals). Data will also be presented with an indication of whether the intervention had a positive effect (+), a negative effect (-), or no statistically significant effect (0).
Studies will be coded within the proposed health systems conceptual framework (see context). Due to expected substantial heterogeneity in study design, exposures, participants and outcomes, and the nature of this systematic review question we do not plan to pool studies in a meta-analysis but instead present a configurative synthesis of the findings. Organizing the findings into the framework will be conducted independently by two reviewers and disagreement will be discussed. Although it is expected that all findings identified in the literature will fit into one of the domains proposed by our proposed framework if new dimensions are identified they will be added and the conceptual framework refined and updated accordingly. The frequency of studies reporting the assessment of each domain will be presented. This research mapping will inform gaps in the current literature and will help to identify areas that require further investigation.
If data allows we plan to conduct subgroup analyses according to geographical regions, national income, and study setting (urban versus rural).
Analysis of subgroups or subsets
If data allow, we plan to conduct subgroup analyses according to geographical regions, national income, and study setting (urban versus rural).
We plan to submit the review for publication in a peer reviewed journal.
Contact details for further information
London School of Hygiene and Tropical Medicine
15-17 Tavistock Place
London WC1H 9SH
Organisational affiliation of the review
London School of Hygiene and Tropical Medicine
Dr Will Maimaris, London School of Hygiene and Tropical Medicine Dr Pablo Perel, London School of Hygiene and Tropical Medicine Dr Helena Legido-Quigley, London School of Hygiene and Tropical Medicine Dr Dina Balabanova, London School of Hygiene and Tropical Medicine Professor Martin McKee, London School of Hygiene and Tropical Medicine
Anticipated or actual start date
14 August 2012
Anticipated completion date
31 December 2012
Conflicts of interest
Subject index terms status
Subject indexing assigned by CRD
Subject index terms
Antihypertensive Agents; Blood Pressure Determination; Health Services Accessibility; Humans; Hypertension
Date of registration in PROSPERO
04 September 2012
Date of publication of this revision
04 September 2012
Stage of review at time of this submission
Piloting of the study selection process
Formal screening of search results against eligibility criteria
Risk of bias (quality) assessment
PROSPERO This information has been provided by the named contact for this review. CRD has accepted this information in good faith and registered the review in PROSPERO. CRD bears no responsibility or liability for the content of this registration record, any associated files or external websites.