Introduction

Hospital-to-home care for children with medical complexity (CMC) and their families is an expanding research area. This is motivated by the substantial increase in numbers of CMC, resulting from medical developments and consequently in the improved life expectancy of children with previously considered untreatable diseases [1, 2]. CMC are defined as children with concurrent chronic conditions, family-identified service needs, functional limitations and high healthcare use [3]. CMC consists of a diverse group of children (e.g. children with severe cerebral palsy or metabolic diseases), and are characterized by frequent emergency department visits, and lengthy and complicated (re)hospitalizations that create pressure on the healthcare system [4, 5]. However, the length of hospital stay of CMC is decreasing [6], and the complex care, such as tracheostomies, enteral feeding tubes, intravenous infusions, dialysis, and complex medication regimens is often provided by families at home [7]. Despite the benefits of being home, caring for CMC is challenging for families, and experiences of parents reveal emotional, social and financial hardships [8,9,10].

The transition from hospital to home of CMC should only take place when parents feel ready, and when the continuity of care is optimally organized. However, this is not always successful [11], and parents do not always feel supported and adequately prepared [12, 13]. Publications on the effectiveness of interventions to support a successful transition from hospital to home of CMC are numerous, with coordination of care, collaboration between families and the multidisciplinary team, and communication as key elements [14, 15]. However, the heterogeneity in outcomes hamper comparisons across trials and therewith the ability to move research forward in this field [16,17,18]. An overview of available outcomes may support researchers and program evaluators in outcome selection. The aim of this systematic review was to summarize and categorize outcomes currently reported in publications evaluating the effectiveness of hospital-to-home transitional care interventions for CMC.

Methods

This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic reviews [19], and the recommendations for a Core Outcome Set development and reporting [20, 21].

We considered this literature review as the first step in developing a Core Outcome Set (COS), an agreed method to overcome problems of variability in outcome selection, measurement and synthesis [22]. The full protocol, describing this systematic review and the next steps (a Delphi study and focus groups), has been registered in the Core Outcome Measures in Effectiveness Trials (COMET) Initiative database [22].

Study eligibility

Search strategy

We searched Medline, EMBASE, Cochrane library, CINAHL, PsychInfo and Web of Science with help of a clinical librarian. The search was limited to articles published in English between 1 January 2010 and 15 March 2023. The search was executed on 15 November 2020, and updated on 18 March 2023. This period was considered adequate for the aim of our study as the reported outcomes may change over time depending on e.g. societal perspective on health and healthcare, and population characteristics. The key terms referring to the patient group included “children with medical complexity” or related terms, such as “children with complex chronic conditions”. The key terms referring to the intervention included “transitional care”, “follow-up” and “discharge”. Comparison interventions and outcomes were not specified in the search. The detailed search strategies are presented in Appendix A. Duplicates were removed electronically; the selection was carried out using the web application Rayyan (http://rayyan.qcri.org).

Inclusion criteria

We included comparative studies evaluating the effectiveness of an intervention to improve the hospital-to-home transition for CMC, e.g. randomized controlled trials, controlled clinical trials, cohort studies, and before-after designs. Studies had to report on quantitative outcomes to be eligible for inclusion. We focused on studies with participants described as children with medical complexity. Studies based in all inpatient settings that provided transitional care were included, as well as all types of interventions or types of care that aimed to improve the hospital-to-home transitional care. We only included studies if full text publications were available.

Exclusion criteria

Publications were excluded if it concerned qualitative research, reviews, guidelines, case studies, editorials and abstracts.

Study selection

Two reviewers independently screened all titles and abstracts to identify potentially relevant studies based on the inclusion criteria. If they could not assess a publication for relevance based on title and abstract, full text was obtained. Subsequently, the two reviewers independently studied the full texts for final inclusion. We used snowball sampling by hand-searched the reference lists of all included articles and relevant (systematic) reviews to identify additional publications. After each step, the reviewers discussed their findings to reach consensus. When disagreement needed to be solved, a third reviewer was consulted.

Data extraction

Data were extracted by one reviewer and verified by a second reviewer. A self-designed extraction form was used. This form was pilot tested by two reviewers by comparing the data extraction results of the first 10 included studies. The following data were systematically collected: first author, publication year, country or origin, design of the study, setting, sample size, medical complexity of the child, age of the child, hospital-to-home intervention studied, outcomes, outcome measures, sources of the outcomes, and the time-frame of the outcome measures. Any outcomes that were described in the studies were included, and no distinction was made between primary and secondary outcomes.

Analysis

A narrative synthesis was undertaken to summarize the outcomes. We anticipated that outcomes would vary in terminology and in measurement tools used. We merged the outcomes with similar definitions and/or concepts. Therefore, two researchers independently reviewed the list of outcomes as reported in the studies to identify similarities. Their findings were discussed in consensus meetings with the multidisciplinary hospital-to-home research group that included pediatricians, a pediatric intensivist, a pediatric rehabilitation specialist, (pediatric) nurses, and a clinical epidemiologist. Two researchers checked the merged outcomes by re-reading the publications.

After comparing several frameworks to classify the outcomes, we decided to use the taxonomy of Dodd et al. [23]. Based on this taxonomy, we categorized the outcomes into the following domains: (a) mortality and survival, (b) physical health, (c) life impact, (d) resource use, and (e) adverse events [23]. We created a domain (f) others to report on those outcomes that would not fit in well, but we considered important to include in this review. The domain mortality and survival includes all-cause mortality and cause-specific mortality. Physical health refers to measures of physiological function, signs and symptoms related to a body system, or general physiological outcomes, such as weight, fatigue and pain. Life impact refers to the impact of a disease or condition on functioning (e.g. social, emotional, and cognitive), quality of life, delivery of care (e.g. compliance), and personal circumstances (e.g. finances, work). Resource use includes outcomes related to healthcare utilization and costs. The domain adverse events includes any unintended consequence of the intervention. Two reviewers categorized the outcomes into one of the six domains. A third reviewer resolved uncertainties.

Results

The database searches resulted in 11.011 records and after elimination of duplicates 8.190 records remained. A total of 8.015 papers were excluded based on title and abstract. After reading the remaining 175 publications full texts, 48 studies were deemed eligible according the pre-defined inclusion and exclusion criteria. Two additional publications were identified from hand searching the reference lists, resulting in a total of 50 studies included in this systematic review [24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73]. Figure 1 shows the selection process.

Fig. 1
figure 1

Study selection process

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Study characteristics

Of the 50 studies, 43 (86%) were performed in pediatric hospitals in the United States of America [24,25,26,27,28, 32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59, 61, 62, 64,65,66,67,68,69,70, 72], three studies in Canada (6%) [30, 31, 60], two in Italy (4%) [63, 73], one in Australia (2%) [29], and one in Turkey (2%) [71]. Fourty one studies (82%) were published between 2016 and 2021 [24,25,26,27,28,29, 32,33,34,35,36,37,38, 40, 42,43,44,45,46,47, 49,50,51,52,53,54,55, 59, 61,62,63, 65,66,67,68,69,70, 72, 7357—]. In total, 29 studies (58%) characterized their study population as CMC, labeled with criteria, but no specific diagnosis [24, 25, 27,28,29,30,31,32,33, 35, 36, 38,39,40,41,42, 44, 46, 47, 49,50,51,52, 56, 59, 61, 63, 68, 73]. Other study populations were based on specific diagnoses: (preterm) neonates (six studies, 12%) [43, 48, 54, 66, 67, 70], neurological conditions or epilepsy (three studies, 6%) [34, 58, 60], and childhood cancer (one study, 2%) [71]. Some publications defined their population based on technology assistance: mechanical ventilation (two studies, 4%) [37, 53], tracheostomy (five studies, 10%) [45, 55, 57, 65, 72], or both (four studies, 8%) [26, 62, 64, 69].

The following designs were described in the publications: cohort studies (22 studies, 44%) [25, 27,28,29, 33, 35,36,37, 40, 41, 43, 53,54,55,56, 58, 59, 63, 66, 67, 70, 73], quality improvement projects with a pre-post design (13 studies, 26%) [24, 26, 38, 42, 45, 50, 51, 61, 62, 64, 65, 68, 72], randomized controlled trials (six studies, 12%) [32, 34, 46, 47, 49, 60], quasi-experimental studies (five studies, 10%) [39, 44, 48, 52, 71], mixed method studies (two studies, 4%) [30, 31], or other (two studies, 4%) [57, 69].

The hospital-to-home interventions studied were mainly multi-faceted including a wide variety of activities, e.g. care coordination, parental education programs, home visits, and telehealth applications. The study characteristics are summarized in Table 1.

Table 1 Characteristics of included studies
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Outcomes

We identified 172 outcomes among the 50 included studies. Our research group extensively reviewed and discussed the outcome list to identify those with similar definitions, wording or meaning. Finally, consensus was reached on a list of 25 unique outcomes that were assigned to the six outcome domains. We present the outcomes per study (Table 1) and per domain (Table 2).

Table 2 Outcomes per domain
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Mortality and survival

Mortality was considered as an outcome in five studies (10%) [26, 32, 46,47,48]. Mortality was reported differently: 1-year mortality [26], number of children deceased during the study period [32, 46, 47], and 30-days mortality [48].

Physical Health

In seven studies (14%) the outcomes referred to disease management [46, 47, 49, 51, 65, 68, 71]. Studies reported on different outcomes: serious illness [46, 47], health deterioration [49], weight on standard growth curve [51], physical development assessments [65], unresolved health issues [68], and physiological care needs, e.g. bowel control and pain [71].

Life impact

This domain was evaluated in 24 studies (48%) [28,29,30,31, 33, 34, 36, 38, 41, 42, 44, 45, 47,48,49, 54, 57, 59, 60, 64, 47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70, 72] and we differentiated 13 outcomes. Five studies reported on outcomes reflecting the impact on the life of the child: quality of life (three studies, 6%) [31, 33, 49], behavioral problems (one study, 2%) [34], and school absences (one study, 2%) [29]. Ten outcomes concerned the impact on the lives of the parents: self-efficacy (nine studies, 18%) [33, 34, 41, 44, 45, 57, 60, 64, 72], the competency of parents to provide care for their child (eight studies, 16%) [36, 41, 45, 57, 60, 69, 70, 72], satisfaction with hospital-to-home transitional care (eight studies, 16%) [33, 38, 42, 44, 45, 48, 68, 70], compliance in terms of missed appointments were explored in four studies (8%) [28, 48, 54, 59], quality of life (three studies, 6%) [30, 31, 33], satisfaction with healthcare in general (three studies, 6%) [30, 47, 49], out-of-pocket expenses (three studies, 6%) [29, 30, 44], satisfaction with family centered care (two studies, 4%) [30, 31], anxiety (one study, 2%) [34], and depression (one study, 2%) [34].

Resource use

The majority of the studies (36 studies, 72%) had chosen outcomes in the domain resource use [25,26,27,28,29,30,31,32, 35, 37,38,39,40, 42,43,44,45,46,47,48,49,50,51,52,53, 55, 56, 58, 59, 61, 62, 65,66,67, 71, 73]. Hospital (re)admission was the most frequently reported outcome (30 studies, 60%) [25,26,27,28,29, 32, 35, 37,38,39,40, 42,43,44,45,46,47,48,49, 52, 53, 55, 56, 58, 59, 61, 62, 66, 71, 73], followed by length of stay in the hospital (19 studies, 38%) [25, 26, 28, 30, 31, 35, 38,39,40, 44, 46, 47, 49, 51, 55, 56, 58, 61, 65], the number of visits to an Emergency Department (19 studies, 38%) [26, 27, 29,30,31, 37, 38, 40, 43,44,45,46,47,48,49, 53, 58, 67, 73], and costs (17 studies, 34%) [25, 26, 29, 31, 32, 35, 37, 38, 40, 43, 46, 47, 50, 51, 53, 55, 56]. Other reported outcomes in this domain were: the number of contacts to an outpatient department/clinic/subspecialist (nine studies, 18%) [28, 31, 46, 47, 58, 71, 73], the number of primary care consultations or visits to a community based clinic (two studies, 4%) [30, 31], services carried out by a pharmacist (one study, 2%) [50], and the number of activities performed by primary care professionals (one study, 2%) [73].

Adverse events

Adverse events in terms of numbers and features of medication and equipment errors at home were assessed in four studies (8%) [45, 54, 63, 68].

Other

Staff perception about the transitional care, in term of feasibility, usability and satisfaction was evaluated in three studies (6%) [24, 30, 41].

Sources of outcome data and outcome measurements

Different data sources and tools were used to evaluate the outcomes. All studies reporting on mortality and healthcare use collected their data from institutional databases, insurance databases, and electronic medical records. Physical health data came from electronic medical records, a telehealth application and a measurement tool. Outcomes on physical health, life impact, adverse events, and staff perception were measured by a big variety of questionnaires or assessment tools. For example, in the studies reporting on life impact, we found 35 different measurement tools, of which several were modified or self-structured. See Table 2.

Period of outcome measurements

The total duration of the study periods varied from three months [24, 45] to 10 years or more [25, 35, 55, 56]. We found great variation in the frequencies and intervals of the outcome measurements. Some studies reported a single observation, while other studies collected outcomes biweekly, monthly, quarterly, six-monthly, or yearly. Some studies included the measurements over time in the analyses [30, 34, 36, 43, 51, 59, 67, 71] and/or gave visual insight in the trends, e.g. with run charts [26, 29, 31, 49, 50, 54, 59, 61]. In general, studies were unclear in reporting their timelines.

Discussion

In this systematic review, we identified outcomes currently reported in publications evaluating the effectiveness of hospital-to-home transitional care interventions for CMC. Despite a substantial degree of heterogeneity in the definitions and descriptions of the outcomes, we agreed on 25 unique outcomes. These outcomes were assigned to six main outcome domains: mortality and survival, physical health, life impact, resource use, adverse events, and others. This overview of outcomes shows the outcomes researchers have prioritized to evaluate hospital-to-home interventions.

We are aware of important previous work by Looman et al. [17] and Barnert et al. [74] that also reports on outcome measures in publications concerning CMC and their families. Looman et al. aim to identify patterns and gaps in classification systems, data, and outcomes in studies of CMC [17]. Barnert et al. aim to contribute to the development of summary measures to describe the health of CMC [74]. Our systematic review is of additional value due to its focus on outcomes used in evaluations of hospital-to-home interventions. In addition, we specifically aim to use this systematic review in the development of a COS in order to standardize and prioritize meaningful outcomes in studies that aim to improve hospital-to-home transitional care interventions for CMC and their families.

Most studies in our review had chosen resource use outcomes, such as visits to an ED, number of hospital admissions, length of hospital stay, and costs, which is congruent with the two aforementioned reviews [17, 74]. The focus on resource use outcomes might reflect the perceived importance by different stakeholders, e.g. policy makers, insurance companies, and healthcare professionals. The importance of resource use outcomes is obvious, as CMC account substantially in healthcare resource use, such as 20% of ED visits at children’s hospitals, and up to 33% of all children’s healthcare costs [4, 75, 76]. Furthermore, resource use outcomes might also be chosen as indicators of physical health, and the extent to which the medical complexity impacts on the child, parents and families.

Many studies in our systematic review had chosen outcomes reflecting the life impact. Within the domain life impact a variety of different outcomes were collected, of which most reflected the impact on the life of parents. The impact on the life of the children was less represented with six studies focusing on the child. We did not find studies reporting on the specific impact on siblings, other members of the family (e.g. grandparents), or family’s interactions. An explanation could be that those themes are more often explored in qualitative studies. To create a comprehensive view of hospital-to-home transitional care another review of qualitative studies should be of additional value. Thomson et al. pointed out that having a CMC may have a major negative impact on the financial situation of a family [8]. This is supported by Barnert et al. who underlined that a comprehensive and continuous health insurance is considered an important contribution to the health of CMC [77]. Apart from three study that reported out-of-pockets expenses [29, 31, 44], no other study in our review reported the financial impact as an outcome. This is in line with a recent review showing that out of 27 studies only three reported on costs of CMC from the family perspective [78].

Outcomes in the domains mortality and survival, and physical health were less represented in our results. It can be reasoned that the outcomes on physical health are associated with resource use, and therefore less chosen. For example, it is likely that disease exacerbations (physical health) result in more ED visits and hospitalizations (resource use outcomes), making resource use outcomes surrogate outcomes for physical health. We identified two studies that explicitly described the seriousness of the disease in terms of death and resource use [46, 47].

Adverse events outcomes were reported in only a few studies. This might be explained by the challenges in identification and reporting. The identification of errors at home depends mainly on self-reporting by parents. Lack of awareness, parents’ perceived value and decision-making of reporting, and non-transparent reporting processes might hamper data in this outcome domain [79]. However, minimizing medical errors was defined as an important outcome for a healthy life for CMC [77].

Population

Although abundant literature exists on CMC, a uniform definition of CMC is lacking [80], and studies might not have been indexed clearly in the literature databases. Therefore, we also included studies that described the participants as children with complex chronic conditions. As a result, the studies included in this review represent a great variety of medical conditions and diseases, and over-inclusion in our study cannot be ruled out. As the aim of this SR was to identify all outcomes relevant for the hospital-to-home transition, we consider the broad inclusion as a strength of this study. On the other hand, also under-inclusion might have occurred as we excluded studies that did not provide a definition or clear description of the medical complexity of the participants. It is remarkable that most included studies are conducted in the USA. As outcome priorities may be influenced by national policy and the organization of care, this may have resulted in missing outcomes considered relevant in other countries.

Period of outcome measurements

Obviously, the timing of outcome measurement in the course of disease is crucial and dependent on the aim of a study. Publication guidelines stress out to publish the rationale for the frequency, time between measurements and duration of the follow-up in studies. Especially in complex care, outcomes should not be considered final endpoints, but rather ongoing indicators of the well-being of patients and their families, and healthcare needs [81, 82]. It can be expected that the outcomes change over time influenced by the dynamic and unpredictable course of the condition of CMC, and the context. Longitudinal measurement should be encouraged, as it provides the opportunity to use results in feedback loops evaluating the impact and connecting the results with treatment, care, and support activities [82, 83].

Limitations

We acknowledge some limitations of this systematic review. Firstly, we did not execute a quality assessment of the studies included in this systematic review. Because the aim of this systematic review was to summarize and categorize the reported outcomes regardless the quality of the study, we believe a quality assessment was not appropriate to address the research question of interest. However, future review of the existing literature is needed to quantify the effects of the interventions, including an assessment of the quality of the evidence, as this will inform the trustworthiness of the reported effectivity of the hospital-to-home interventions. Secondly, the final set of unique outcomes was established by consensus among the researchers. Despite the expertise of the researchers and the conscientious and careful process, subjective interpretations might have been of influence. In future research, validation by an independent group of experts might increase the trustworthiness of the results.

Conclusion

This systematic review found a big variety of outcomes used in studies evaluating interventions to improve hospital-to-home transition for CMC. However, it was possible to summarize them in a short-list with 25 unique outcomes that reflect mortality, physical health, impact on the life of the child and the parents, resource use, adverse events and staff perceptions. This short-list may support researchers and program evaluators in outcome selection, and can be used in the development of a core outcome set transitional care for CMC in future.