Patient-reported outcomes in multimorbidity intervention research: A scoping review

Network of doctors for multimorbidity and diabetes - the NOMAD intervention: protocol for feasibility trial of multidisciplinary team conferences for people with diabetes and multimorbidity

BACKGROUND

The prevalence of diabetes and coexisting multimorbidity rises worldwide. Treatment of this patient group can be complex. Providing an evidence-based, coherent, and patient-centred treatment of patients with multimorbidity poses a challenge in healthcare systems, which are typically designed to deliver disease-specific care. We propose an intervention comprising multidisciplinary team conferences (MDTs) to address this issue. The MDT consists of medical specialists in five different specialities meeting to discuss multimorbid diabetes patients. This protocol describes a feasibility test of MDTs designed to coordinate care and improve quality of life for people with diabetes and multimorbidity.

METHODS

A mixed-methods one-arm feasibility test of the MDT. Feasibility will be assessed through prospectively collected data. We will explore patient perspectives through patient-reported outcomes (PROs) and assess the feasibility of electronic questionnaires. Feasibility outcomes are recruitment, PRO completion, technical difficulties, impact of MDT, and doctor preparation time. During 17 months, up to 112 participants will be recruited. We will report results narratively and by the use of descriptive statistics. The collected data will form the basis for a future large-scale randomised trial.

DISCUSSION

A multidisciplinary approach focusing on better management of diabetic patients suffering from multimorbidity may improve functional status, quality of life, and health outcomes. Multimorbidity and diabetes are highly prevalent in our healthcare system, but we lack a solid evidence-based approach to patient-centred care for these patients. This study represents the initial steps towards building such evidence. The concept can be efficiency tested in a randomised setting, if found feasible to intervention providers and receivers. If not, we will have gained experience on how to manage diabetes and multimorbidity as well as organisational aspects, which together may generate hypotheses for research on how to handle multimorbidity in the future.

ADMINISTRATIVE INFORMATION

Protocol version: 01 TRIAL REGISTRATION: NCT05913726 - registration date: 21 June 2023.

Caring for high-need patients

OBJECTIVE

We aimed to explore the construct of "high need" and identify common need domains among high-need patients, their care professionals, and healthcare organizations; and to describe the interventions that health care systems use to address these needs, including exploring the potential unintended consequences of interventions.

METHODS

We conducted a modified Delphi panel informed by an environmental scan. Expert stakeholders included patients, interdisciplinary healthcare practitioners (physicians, social workers, peer navigators), implementation scientists, and policy makers. The environmental scan used a rapid literature review and semi-structured interviews with key informants who provide healthcare for high-need patients. We convened a day-long virtual panel meeting, preceded and followed by online surveys to establish consensus.

RESULTS

The environmental scan identified 46 systematic reviews on high-need patients, 19 empirical studies documenting needs, 14 intervention taxonomies, and 9 studies providing construct validity for the concept "high need." Panelists explored the construct and terminology and established that individual patients' needs are unique, but areas of commonality exist across all high-need patients. Panelists agreed on 11 domains describing patient (e.g., social circumstances), 5 care professional (e.g., communication), and 8 organizational (e.g., staffing arrangements) needs. Panelists developed a taxonomy of interventions with 15 categories (e.g., care navigation, care coordination, identification and monitoring) directed at patients, care professionals, or the organization. The project identified potentially unintended consequences of interventions for high-need patients, including high costs incurred for patients, increased time and effort for care professionals, and identification of needs without resources to respond appropriately.

CONCLUSIONS

Care for high-need patients requires a thoughtful approach; differentiating need domains provides multiple entry points for interventions directed at patients, care professionals, and organizations. Implementation efforts should consider outlined intended and unintended downstream effects on patients, care professionals, and organizations.

Effectiveness of continuity of care in reducing depression symptoms in elderly: A systematic review and meta-analysis

BACKGROUND

Depression affects 10%-20% of older adults worldwide. The course of late-life depression (LLD) is often chronic, with a poor long-term prognosis. Lower treatment adherence, stigma, and suicide risk lead to significant challenges in the continuity of care (COC) for patients with LLD. Elderly patients with chronic diseases can benefit from COC. As a common chronic disease of the elderly, whether depression can also benefit from COC has not been systematically reviewed.

METHODS

Systematic literature search in Embase, Cochrane Library, Web of Science, Ovid, PubMed and Medline. Randomized Controlled Trials (RCTs) on the intervention effects of COC and LLD, published on 12 April 2022, were selected. Two independent researchers made research choices based on consensus. An RCT with COC as an intervention measure for the elderly with depression 60 years old was the inclusion criteria.

RESULTS

A total of 10 RCTs involving 1557 participants were identified in this study. The findings showed that: (1) COC significantly reduced depressive symptoms compared to usual care (standardized mean difference [SMD] = -0.47, 95% confidence interval: -0.63 to -0.31), with the best improvement at 3- to 6-month follow-up; (2) The reduction in depressive symptoms was more pronounced for patients with comorbid chronic conditions with LLD (SMD = -0.93, 95% CI: -1.18 to -0.68); (3) COC was more effective than other regions for LLD in Europe and the Americas (SMD = -0.84, 95% CI: -1.07 to -0.61); and (4) COC had a positive impact on the quality of life of patients with LLD (SMD = 0.21, 95% CI: 0.02-0.40).

LIMITATIONS

The included studies included several multi-component interventions with widely varying methods. Therefore, it was almost impossible to analyze which of these interventions had an impact on the assessed outcomes.

CONCLUSIONS

This meta-analysis shows that COC can significantly reduce depressive symptoms and improve quality of life in patients with LLD. However, when treating and caring for patients with LLD, health care providers should also pay attention to timely adjustments of intervention plans according to follow-up, synergistic interventions for multiple co-morbidities, and actively learning from advanced COC programs at home and abroad to improve the quality and effectiveness of services.

Development of a standard set of PROs and generic PROMs for Dutch medical specialist care : Recommendations from the Outcome-Based Healthcare Program Working Group Generic PROMs

PURPOSE

The added value of measuring patient-reported outcomes (PROs) for delivering patient-centered care and assessment of healthcare quality is increasingly evident. However, healthcare system wide data collection initiatives are hampered by the proliferation of patient-reported outcome measures (PROMs) and conflicting data collection standards. As part of a national initiative of the Dutch Ministry of Health, Welfare and Sport we developed a consensus-based standard set of generic PROs and PROMs to be implemented across Dutch medical specialist care.

METHODS

A working group of mandated representatives of umbrella organizations involved in Dutch medical specialist care, together with PROM experts and patient organizations worked through a structured, consensus-driven co-creation process. This included literature reviews, online expert and working group meetings, and feedback from national patient- and umbrella organizations. The 'PROM-cycle' methodology was used to select feasible, valid, and reliable PROMs to obtain domain scores for each of the PROs included in the set.

RESULTS

Eight PROs across different domains of health were ultimately endorsed: symptoms (pain & fatigue), functioning (physical, social/participation, mental [anxiety & depression]), and overarching (quality of life & perceived overall health). A limited number of generic PROMs was endorsed. PROMIS short forms were selected as the preferred instruments for all PROs. Several recommendations were formulated to facilitate healthcare system level adoption and implementation of the standard set.

CONCLUSIONS

We developed a consensus-based standard set of Generic PROMs and a set of recommendations to facilitate healthcare system wide implementation across Dutch medical specialist care.

Conceptualisation of a measurement framework for Needs-based Quality of Life among patients with multimorbidity

Background

Multimorbidity is both an individual and societal problem. For society, patients with multimorbidity increase healthcare costs. For the individual, living with multimorbidity is complex, and there is an inverse relationship between a patient's Quality of Life (QoL) and their number of chronic conditions. Numerous intervention studies target these problems, yet there is no multimorbidity-specific patient-reported outcome measure (PROM) developed specifically for this group with adequate measurement properties to assess QoL. This study explores what overall needs regarding QoL are affected by living with multimorbidity through qualitative interviews. With this, we conceptualise Needs-based QoL specifically for this group, ensuring high content validity (regarding relevance and comprehensiveness) of using the Needs-based approach to measure their QoL. This is essential as this preliminary study leads to the development of the MultiMorbidity Questionnaire (MMQ), a PROM measuring QoL among patients with multimorbidity.

Methods

This study draws upon qualitative interviews with fifteen patients with multimorbidity based on a semi-structured interview guide following the Needs-based approach. This approach allowed the patients to cover needs relevant for their QoL in relation to the complexities of living with multimorbidity. The transcribed interviews were thematically analysed, inspired by Braun and Clarke’s reflexive approach.

Results

Analysis of the interviews resulted in the construction of six intertwined domains relevant to patients with multimorbidity, covering their Needs-based QoL; “Physical ability”, “Self-determination”, “Security”, “Partner and social life”, “Self-image”, and “Personal finances”. “Physical limitations” and “Personal finances” were stated as core needs implicating the other domains.

Conclusion

This study shows six intertwined overall domains relevant for patients with multimorbidity regarding their Needs-based QoL; “Physical ability”, “Self-determination”, “Security”, “Partner and social life”, “Self-image”, and “Personal finances”. These needs are relevant in a Danish context, with a generally high standard of living. Based on this conceptual framework of Need-based QoL for patients with multimorbidity, we will develop items for a new patient-reported outcome measure called the MMQ.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-022-00489-0.

The participatory development of a national core set of person-centred diabetes outcome constructs for use in routine diabetes care across healthcare sectors

BACKGROUND

This study sought to utilise participatory research methods to identify the perspectives of people with diabetes regarding which diabetes outcomes were most important to them. These findings were then used to support an expert working group representing multiple health sectors and healthcare disciplines and people with diabetes to establish a core set of patient-important outcome constructs for use in routine diabetes care.

METHODS

26 people with diabetes and family members were recruited through purposive sampling to participate in interviews, focus groups, voting and plenary activities in order to be part of identifying outcome constructs. Content and qualitative analysis methods were used with literature reviews to inform a national multi-stakeholder consensus process for a core set of person-centred diabetes outcome constructs to be used in routine diabetes care across health care settings.

RESULTS

21 people with diabetes and 5 family members representing type 1 and 2 diabetes and a range of age groups, treatment regimens and disease burden identified the following patient-reported outcome constructs as an important supplement to clinical indicators for outcome assessment in routine diabetes care: self-rated health, psychological well-being, diabetes related emotional distress and quality of life, symptom distress, treatment burden, blood sugar regulation and hypoglycemia burden, confidence in self-management and confidence in access to person-centred care and support. Consensus was reached by a national multi-stakeholder expert group to adopt measures of these constructs as a national core diabetes outcome set for use in routine value-based diabetes care.

CONCLUSIONS

We found that patient-reported outcome (PRO) constructs and clinical indicators are needed in core diabetes outcome sets to evaluate outcomes of diabetes care which reflect key needs and priorities of people with diabetes. The incorporation of patient-reported outcome constructs should be considered complementary to clinical indicators in multi-stakeholder value-based health care strategies. We found participatory research methods were useful in facilitating the identification of a core prioritised set of diabetes outcome constructs for routine value-based diabetes care. The use of our method for involving patients may be useful for similar efforts in other disease areas aimed at defining suitable outcomes of person-centred value-based care. Future research should focus on developing acceptable and psychometrically valid measurement instruments to evaluate these outcome constructs as part of routine diabetes care.

Evaluating the content of a patient-reported outcome measure for people with multimorbidity: a Delphi consensus

PURPOSE

Evidence supporting multimorbidity-adapted interventions is scarce, mostly due to a lack of adapted outcome measures. Measurement constructs for a novel patient-reported outcome measure (PROM) were defined in previous studies using a literature review, a qualitative description from stakeholders, and an item pool identification process. The aim of this study was to attain consensus on the content of this novel PROM.

METHODS

A three-round electronic modified Delphi technique was conducted using an academic and clinical expert panel. Using a Likert scale, the panel rated the relevance, improvability, and self-ratability of each construct and item of the preliminary version of the PROM. The main outcome was consensus attainment, defined as strong (≥ 70%), moderate (50-69%) or low agreement (< 50%). Constructs and items with strong consensus were kept, moderate were sent to the next round and low agreement were rejected.

RESULTS

From the 61 experts contacted, 39 participated in the first round of the Delphi, with a 12.8% attrition at the second round (n = 34) and 38.2% at the third round (n = 21). The panel included mostly female academic experts from nursing and medicine backgrounds. The preliminary PROM included 19 constructs and 70 items; from these, 16 constructs and 50 items attained consensus. The consensus attainment process excluded three constructs and their items: awareness, weight control and social integration.

CONCLUSION

Consensus was reached for a patient-reported outcome measure adapted for people with multimorbidity including 50 relevant, improvable and self-ratable items categorized under 16 constructs. As more interventions tailored to multimorbidity are implemented, there is an increasing need for a valid measure of the effectiveness of these interventions.

Self-Reported Satisfaction to Treatment, Quality of Life and General Health of Type 2 Diabetes Patients with Inadequate Glycemic Control from North-Eastern Romania

Type 2 diabetes mellitus (T2DM) undermines health and quality of life (QoL). This cross-sectional study surveyed 138 consenting T2DM patients from North-Eastern Romania with regard to their satisfaction with treatment, diabetes-related impact on QoL, and general health. The Romanian versions of Diabetes Treatment Satisfaction Questionnaire (DTSQ), Audit of Diabetes Dependent Quality of Life (ADDQoL-19), and 36-Item Short Form Health Survey (SF-36) questionnaires were used. Self-reports were analyzed in conjunction with clinical and metabolic profiling. The patients were 57.86 ± 8.82 years old, 49.3% men, treated with oral glucose-lowering drugs, presenting with inadequate glycemic control but without cardiovascular manifestations. The mean DTSQ and ADDQoL scores were 25.46 ± 0.61 and −2.22 ± 1.2, respectively. Freedom to eat, holidays, journeys, leisure, physical health, sex life, freedom to drink, and feelings about the future scored below average. The mean SF-36 physical and mental health scores were 47.78 ± 1.03 and 50.44 ± 1.38, respectively. The mean SF-6D score was 0.59 ± 0.04 (generated retrospectively using SF-36 data). Negative associations were significant between ADDQoL, age (r = −0.16), and body mass index (r = −0.23), p < 0.01. Overall scores did not correlate with diabetes duration (except DTSQ, r = −1.18, p = 0.02) or HbA_1c. The results confirm other researchers’ findings in Europe and nearby countries. Our patients seemed satisfied with treatment despite glycemic imbalance and viewed diabetes as a burden on QoL and especially freedom to eat.

Understanding patient outcomes to develop a multimorbidity adapted patient-reported outcomes measure: a qualitative description of patient and provider perspectives

Background

Multimorbidity is a complex health situation that requires interventions tailored to patient needs; the outcomes of such interventions are difficult to evaluate. The purpose of this study was to describe the outcomes of patient-centred interventions for people with multimorbidity from the patients’ and healthcare providers’ perspectives.

Methods

This study followed a qualitative descriptive design. Nine patients with multimorbidity and 18 healthcare professionals (nurses, general practitioners, nutritionists, and physical and respiratory therapists), participating in a multimorbidity-adapted intervention in primary care were recruited. Data were collected using semi-structured interviews with 12 open-ended questions. Triangulation of disciplines among interviewers, research team debriefing, data saturation assessment and iterative data collection and analysis ensured a rigorous research process.

Results

Outcome constructs described by participants covered a wide range of themes and were grouped into seven outcome domains: Health Management, Physical Health, Functional Status, Psychosocial Health, Health-related Behaviours, General Health and Health Services. The description of constructs by stakeholders provides valuable insight on how outcomes are experienced and worded by patients.

Conclusion

Participants described a wide range of outcome constructs, which were relevant to and observable by patients and were in line with the clinical reality. The description provides a portrait of multimorbidity-adapted intervention outcomes that are significant for the selection and development of clinical research outcome measures.

Investigation of a Mobile Health Texting Tool for Embedding Patient-Reported Data Into Diabetes Management (i-Matter): Development and Usability Study

Background

Patient-reported outcomes (PROs) are increasingly being used in the management of type 2 diabetes (T2D) to integrate data from patients’ perspective into clinical care. To date, the majority of PRO tools have lacked patient and provider involvement in their development, thus failing to meet the unique needs of end users, and lack the technical infrastructure to be integrated into the clinic workflow.

Objective

This study aims to apply a systematic, user-centered design approach to develop i-Matter (investigating a mobile health [mHealth] texting tool for embedding patient-reported data into diabetes management), a theory-driven, mobile PRO system for patients with T2D and their primary care providers.

Methods

i-Matter combines text messaging with dynamic data visualizations that can be integrated into electronic health records (EHRs) and personalized patient reports. To build i-Matter, we conducted semistructured group and individual interviews with patients with T2D and providers, a design thinking workshop to refine initial ideas and design the prototype, and user testing sessions of prototypes using a rapid-cycle design (ie, design-test-modify-retest).

Results

Using an iterative user-centered process resulted in the identification of 6 PRO messages that were relevant to patients and providers: medication adherence, dietary behaviors, physical activity, sleep quality, quality of life, and healthy living goals. In user testing, patients recommended improvements to the wording and timing of the PRO text messages to increase clarity and response rates. Patients also recommended including motivational text messages to help sustain engagement with the program. The personalized report was regarded as a key tool for diabetes self-management by patients and providers because it aided in the identification of longitudinal patterns in the PRO data, which increased patient awareness of their need to adopt healthier behaviors. Patients recommended adding individualized tips to the journal on how they can improve their behaviors. Providers preferred having a separate tab built into the EHR that included the personalized report and highlighted key trends in patients’ PRO data over the past 3 months.

Conclusions

PRO tools that capture patients’ well-being and the behavioral aspects of T2D management are important to patients and providers. A clinical trial will test the efficacy of i-Matter in 282 patients with uncontrolled T2D.

Trial Registration

ClinicalTrials.gov NCT03652389; https://clinicaltrials.gov/ct2/show/NCT03652389

How can we improve specialist health services for children with multi-referrals? Parent reported experience

Background

Children with combined mental and somatic conditions pose a challenge to specialized health services. These cases are often characterized by multi-referrals, frequent use of health services, poor clinical and cost effectiveness, and a lack of coordination and consistency in the care. Reorganizing the health services offered to these children seems warranted. Patient reported experiences give important evidence for evaluating and developing health services. The aim of the present descriptive study was to explore how to improve specialist health services for children with multiple referrals for somatic and mental health conditions. Based on parent reported experiences of health services, we attempted to identify key areas of improvement.

Methods

As part of a larger, ongoing project; “Transitioning patients’ Trajectories”, we asked parents of children with multiple referrals to both somatic and mental health departments to provide their experiences with the services their children received. Parents/guardians of 250 children aged 6–12 years with multi-referrals to the Departments of Pediatrics and Child and Adolescent Mental Health at Haukeland University Hospital between 2013 and 2015 were invited. Their experience was collected through a 14 items questionnaire based on a generic questionnaire supplied with questions from parents and health personnel. Possible associations between overall experience and possible predictors were analyzed using bivariate regression.

Results

Of the 250 parents invited, 148 (59%) responded. Mean scores on single items ranged from 3.18 to 4.42 on a 1–5 scale, where five is the best possible experience. In the multiple regression model, perception of wait time (r = .56, CI = .44–.69 / β = 0.16, CI = .05–.28), accommodation of consultations (r = .71, CI = .62–.80 / β = 0.25, CI = .06–.45 / β = 0.27, CI = .09–.44), providing adequate information about the following treatment (r = .66, CI = .55–.77 / β = 0.26, CI = .09–.43), and collaboration between different departments at the hospital (r = .68, CI = .57–.78 / β = 0.20, CI = -.01–.40) were all statistically significantly associated with parents overall experience of care.

Conclusions

The study support tailored interdisciplinary innovations targeting wait time, accommodation of consultations, communication regarding the following treatment and collaboration within specialist health services for children with multi-referrals to somatic and mental specialist health care services.

What nursing sensitive outcomes have been studied to-date among patients cared for in intensive care units? Findings from a scoping review

BACKGROUND

Although many studies have considered mortality and adverse effects as outcomes sensitive to nursing practice, it seems that other outcomes of nursing care in intensive care units have been explored less commonly.

OBJECTIVES

To describe the state-of-science in research in the field of nursing sensitive outcomes in intensive care units and to synthesize outcomes that have been documented to date as being influenced by nursing care.

DESIGN

A scoping review study based on the framework proposed by Arksey and O'Malley, further refined by the Levac and Joanna Briggs Institute was performed in 2019.

DATA SOURCES

The Medline, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Scopus, and Google Scholar electronic databases were searched. In addition, the reference list of included articles was screened.

REVIEW METHODS

Two researchers independently identified publications on the basis of the following criteria: (a) articles that reported nursing sensitive outcomes on critically-ill adult patients admitted to the intensive care unit, (b) as primary and secondary studies, (c) written in English, and (d) without any time frame limitation.

RESULTS

Of the 4,231 records, 112 fully met the inclusion criteria and were included. Publications were mainly authored in the US and Canada (n = 44, 39.2%), and the majority (n = 62, 55.3%) had an observational design. A total of 233 nursing sensitive outcomes emerged, categorized in 35 outcomes, with, on average, two per study included. The most often measured outcomes were pressure ulcers (20 studies) and ventilator-associated pneumonias (19 studies); the less studied outcomes were quality of life, secretion clearance, patient-ventilator dysynchrony, and post-extubation dysphagia. When categorizing outcomes, the ones concerning safety (n = 77, 33.1%) were represented the most, followed by those concerning the clinical (n = 72, 30.9%), functional (n = 70, 30.0%), and perceptual (n = 14, 6.0%) domains. The interdependent outcomes linked to multi-professional interventions (e.g., ventilator-associated pneumonias) were the most frequently studied nursing sensitive outcomes (n = 20, 57.1%), while independent outcomes resulting from autonomous interventions performed by nurses were less often studied (n = 8, 22.9%).

CONCLUSIONS

From a clinical point of view, a large heterogeneity of outcomes influenced by nursing care emerged. However, identified outcomes have been studied with different approaches and metrics, so that future efforts will need to establish homogeneous conceptual and operative definitions. Moreover, increasing efforts in establishing perceptual outcomes, or those close to the fundamentals of nursing care, are suggested in order to better depict the contribution of critical care nurses in the field.

Effectiveness of interventions for managing multiple high-burden chronic diseases in older adults: a systematic review and meta-analysis

INTRODUCTION

More than half of older adults (age ≥ 65 yr) have 2 or more high-burden multimorbidity conditions (i.e., highly prevalent chronic diseases, which are associated with increased health care utilization; these include diabetes [DM], dementia, depression, chronic obstructive pulmonary disease [COPD], cardiovascular disease [CVD], arthritis, and heart failure [HF]), yet most existing interventions for managing chronic disease focus on a single disease or do not respond to the specialized needs of older adults. We conducted a systematic review and meta-analysis to identify effective multimorbidity interventions compared with a control or usual care strategy for older adults.

METHODS

We searched bibliometric databases for randomized controlled trials (RCTs) evaluating interventions for managing multiple chronic diseases in any language from 1990 to December 2017. The primary outcome was any outcome specific to managing multiple chronic diseases as reported by studies. Reviewer pairs independently screened citations and full-text articles, extracted data and assessed risk of bias. We assessed statistical and methodological heterogeneity and performed a meta-analysis of RCTs with similar interventions and components.

RESULTS

We included 25 studies (including 15 RCTs and 6 cluster RCTs) (12 579 older adults; mean age 67.3 yr). In patients with [depression + COPD] or [CVD + DM], care-coordination strategies significantly improved depressive symptoms (standardized mean difference -0.41; 95% confidence interval [CI] -0.59 to -0.22; I2 = 0%) and reduced glycosylated hemoglobin (HbA1c) levels (mean difference -0.51; 95% CI -0.90 to -0.11; I2 = 0%), but not mortality (relative risk [RR] 0.79; 95% CI 0.53 to 1.17; I2 = 0%). Among secondary outcomes, care-coordination strategies reduced functional impairment in patients with [arthritis + depression] (between-group difference -0.82; 95% CI -1.17 to -0.47) or [DM + depression] (between-group difference 3.21; 95% CI 1.78 to 4.63); improved cognitive functioning in patients with [DM + depression] (between-group difference 2.44; 95% CI 0.79 to 4.09) or [HF + COPD] (p = 0.006); and increased use of mental health services in those with [DM + (CVD or depression)] (RR 2.57; 95% CI 1.90 to 3.49; I2 = 0%).

INTERPRETATION

Subgroup analyses showed that older adults with diabetes and either depression or cardiovascular disease, or with coexistence of chronic obstructive pulmonary disease and heart failure, can benefit from care-coordination strategies with or without education to lower HbA1c, reduce depressive symptoms, improve health-related functional status, and increase the use of mental health services.

PROTOCOL REGISTRATION

PROSPERO-CRD42014014489.