Steps 1 & 2: Selecting a concept and determining the purpose of the analysis
In Step 1, to inform research, policy, and practice, we selected the concept “children with complex health conditions” (CCHC). In Step 2, we determined the purpose of the analysis, which was to clarify the meaning of CCHC. We focused on this concept because it is broad, including all types of physical, mental, neurological, and/or behavioural conditions or disabilities, with or without diagnosis. CCHC’s needs may or may not emerge from chronic illnesses, symptoms’ severity, clinical care, or from possible comorbidity of conditions. Care needs are considered complex when compared to the needs of the general population of children.
Step 3: Identifying the uses of the concept
This step identified the use of the concept and related terms, integrating findings from the published and grey literature, and from stakeholder interviews.
Published literature: We focused on the many terms for CCHC, which are often used interchangeably, leading to confusion. These terms included children with special health care needs, complex chronic conditions, and medically fragile children, among others. Since 1998, the Maternal and Child Health Bureau (MCHB) has defined “children with special health care needs" (CSHCN) as having or being at increased risk of having a chronic physical, mental, developmental, or behavioural condition, requiring health and related services of a type or amount beyond that required by children generally .
Another commonly used term for CCHC was "complex chronic conditions" (CCCs) [12-17], defined as involving one or more chronic conditions . In studies [19-22] that drew on Feudtner et al. [12, 23], CCCs were conditions that may be expected to last at least 12 months, unless death occurs before, and to involve different organ systems or one organ system severely enough to require speciality care or hospitalizations. In a theoretical paper  and in empirical studies [14, 17], the authors focused on children with “life-threatening”  and “life-limiting” conditions , forming a sub-sample of CCHC, namely those with medical complexities and in palliative care. A doctoral dissertation on palliative care used terminal and life-threatening illnesses interchangeably . Similarly, in a book on palliative and end of life care, Grinyer and Barbrachild  resorted to the terms "self-limiting" and "life threatening illnesses" as a sub-category of CCHC. Although this term is usually applied to cancer diagnoses, the focus may be HIV/AIDS . Other definitions focused on palliative conditions that could be either life-threatening (cure is possible) or life-limiting (no hope for a cure) .
Another used term for CCHC is "special health care needs children" . Again, there was a sub-group of "medically complex" or "medically fragile" children , including those with intense needs due to multisystem conditions, technology dependence, or complex treatments. These CCHC, the most medically complex cases . Hall [25 p. 179], were considered to have "medically complex chronic disease" or even "multisystem chronic disease". Both terms refer to the "involvement with multiple subspecialists and medical technology or device dependence" (e.g., gastrostomy tubes, tracheostomies, etc.). Some studies focused on specific conditions, such as cerebral palsy , hemophilia A, B or Factor VII (FVII) deficiency , or medical complexities with a common denominator, such as incontinence .
In sum, there were many terms for CCHC and related terms that were used interchangeably, which may cause confusion. Implicit in the definition of “children with special health care needs” by the 1998 Maternal and Child Health Bureau  is the uniqueness of each child, family, and condition, whether diagnosed or at risk of a condition. The term "complex chronic conditions" recognized the varying extent of severity due to comorbidity. Finally, in the term "special health care needs children" emphasis was put on the child’s developmental age, which refers to their age of functioning physically, socio-emotionally, or cognitively.
Grey literature: Some North American governmental websites and/or non-governmental organizations (Canadian provinces, American states) considered CCHC to include children who have chronic conditions when they last over 6-12 months [29, 30]. In Canada, using the MCBH’s definition [11, 31] that was endorsed by van der Lee et al. , the PEI’s Minister of Health and Wellness developed a definition of children with special needs as follows: "Children and youth up to the age of 18 years of age and their families who require significant additional health, social, environmental, educational support–beyond that which is required by children in general–to enhance or improve their health, development, learning, quality of life, participation, and community inclusion" [32 p. 2].
In contrast to this broad definition [33, 11], the Complex Care for Kids Ontario strategy [34 p. 1] used a standard operational definition for the sub-group of medical complexity, referring to these CCHC as "technology dependent and/or users of high intensity care, fragility, chronicity and complexity". These conditions last at least 6 months but death may occur earlier . The Children’s Hospital Association , which represents over 220 American children’s hospitals, used the terms "medically complex children" or "children with medical complexities" or "children with medically complex conditions" to refer to highly demanding pediatric patients . Based on the 3MTM Clinical Risk Groups , which is a classification system and risk-adjustment tool that measures burden of illness, CCHC may fall into five categories, including non-chronic, episodic chronic (12 months long and likely episodic; not likely lasting into adulthood), lifelong chronic, and complex chronic or malignancies. There may be chronic conditions in one/more body systems or a single dominant condition .
In sum, CCHC’s conditions were persistent in either one dominant illness/disability or more bodily systems, lasting beyond 6 or 12 months. CCHC was used as a broad concept, including cases with dependency on technology, high intensity care use, and with highly complex or chronic conditions (fitting with the published literature’s medical complexity).
Stakeholders: In descending order, the most commonly reported elements of the definition of CCHC as used by the stakeholders were as follows:
(1) A single definition for all types of conditions, including physical/organic (e.g., brain diseases), mental/addictions, and behavioural conditions that require management that is "long-term" or "on-going", across the "lifespan" or "lifelong" (n = 84);
(2) Needs that require support from a high number of professionals, including those across sectors such as social services (n = 62);
(3) Severity (n = 52) in the form of the complexity of conditions (involving one or more bodily systems) or impaired quality of life, resulting in family stress or additional developmental needs. Some stakeholders (n = 26 of 52) added: all the defining elements may apply at one time but not at another (e.g., remission); Others (n = 16 of 52) added that it is probably more difficult to identify cases involving less severe cases and that a definition would need to capture these cases.
(4) Strictly medical organic/physical problems (n = 17), in contrast with the most commonly reported element around the need for a broader lens (see 1 above); and
(5) A broad range of age at the time of diagnosis, starting from conception (n = 14);
Less commonly reported elements of the stakeholders’ definitions of CCHC were as follows:
(1) Functional problems where CCHC may feel better at times (n = 3);
(2) A forgotten positive connotation of the term "chronic conditions" where children now generally live longer with long-term management (n = 2);
(3) Limited school attendance (n = 2);
(4) Difficulty of receiving support, regardless of the conditions’ degree of severity (n = 2);
(5) The need to travel for care (n = 1),
(6) The need to not have a vague broad definition (n = 1);
(7) The inclusion of chronic pain (n = 1)
(8) A focus on medical frailty (n = 1);
(9) Families’ own appraisal of conditions and coping (n = 1); and
(10) Refugee-related needs (n = 1) where CCHC’s conditions may become more complex because of the need for an interpreter in schools, a lack of knowledge of medical background, and complex needs (n = 1).
Many stakeholders reported a need for a broader definition than the one developed by McPherson et al. (or MCHB) [11, 31] that includes:
(1.1). chronic conditions that endure for at least 6 months; or
(1.2). cognitive learning disabilities, especially without early support and where the
child can develop mental illnesses;
(1.3). conditions that do not respond to treatment;
(1.4). short-lived conditions (when severe enough);
Step 4: Determining the defining attributes
Similar to signs or symptoms, defining attributes are critical characteristics that assist in clarifying concepts and differentiating them from their related concepts . This fourth step described the characteristics most commonly related to CCHC in the family representatives’ perspectives and in the literature.
First, the family representatives we consulted raised the following points that were included in our search strategy: (1) the concept of "CCHC" would not be complete without the inclusion of "psychosomatic conditions" (involving the mind and body); (2) a broad definition of CCHC because of commonly comorbid conditions; and (3) the term “children with complex health needs” would capture CCHC’s unique and complex daily life.
Second, to frame the defining attributes of CCHC, we drew on the existing definitions of CCHC and of related concepts, which were referred to in Step 3 and summarized herein as follows: children with special health care needs [CSHCN] [26, 36-39], children with special school health needs, children with complex chronic conditions [CCCs] [12, 23, 40-42] or children with pediatric chronic conditions [7, 43, 44], life-threatening and life-limiting conditions [5, 45], children with medical complexity (CMC) (e.g., children with severe neuro-disabilities [4, 46-48], and particular conditions, including genetic or developmental ones .
The prevalence estimates of CCHC varied from 0.22% to 44% . This wide range of estimates depended on different operationalizations of definitions in addition to multiple informants, types of data, and years of publication. It is not surprising then that van der Lee et al. (2007) defined "complex chronic conditions" as "commonly requiring multidisciplinary input". In some studies in van der Lee et al.’s systematic review , CCHC were defined by their developmental stage. Bearing this in mind, one must consider that human development is embedded in a broader socio-cultural context. For CCHC, this context includes factors such as their immediate/larger families, schools, neighborhoods, communities, culture, and peers, among others. For example, a child develops as whole but also simultaneously in domains (physical, motor, socio-emotional, cognitive, etc.). This development is fostered by a loving family, through relationships with parents, siblings, relatives, neighbours, and community members, among others. In addition, a child has relationships with siblings, peers, school educators, and other adults.
Finally, to determine the defining attributes of the concept of CCHC, we integrated the findings from stakeholder interviews and the literature. The defining attributes were: (1) breadth of conditions, with or without diagnosis, possibly comorbid, resulting in multiple care needs and requiring services often across settings ; (2) uniqueness of each child; (3) varying extent of severity at different time points; (4) importance of developmental age; and (5) uniqueness of each family’s context, namely within a broader socio-cultural context. Taken together, there were breadth and uniqueness of conditions, severity, and of required services, resulting in a need for broader definitions of CCHC.
Step 5: Identifying the model case
A typical example of CCHC is Mathew, a 7-year-old boy from a remote village in Canada who was born with a congenital condition that limits his mobility, delays his development, and impacts his daily life. His single mother must regularly leave her job for a few days to travel to a larger city for appointments with a physiotherapist, speech pathologist, and pediatrician. Occasionally, she must drive out of province to a children’s hospital for yet another surgery for her son. She worries about time off from her job. She is afraid of being fired when she needs to bring bread to her family’s table. Furthermore, she is concerned about the icy roads in the winter. She often feels lost, overwhelmed, frustrated or frightened whilst dealing with all the professionals taking care of her son. Confronted with fragmented services, she regularly repeats Mathew’s story over and over every time she meets with a new health care provider. She attends her son’s school on a regular basis to educate teachers about his condition and to advocate for his basic needs, such as easier physical access to a washroom. She often feels guilty about her son’s behavioural problems in school.
This model case includes all the defining attributes of CCHC determined in Step 4, which are as follows: (1) The elements of the MCHB’s (1998)’s definition [11, 31], namely one or more chronic condition, requiring different services, namely physiotherapy, speech pathology, pediatrics, surgery, and school accommodation; (2) Uniqueness of the child and his condition (7-year-old boy, growing up with a condition in a remote village that requires multiple, long-distance services; (3) Varying extent of severity (birth condition that impacts daily life); (4) The importance of developmental age (limited mobility and delayed development); and (5) Uniqueness of family’s context (time off work/school, parental advocacy, effort to re-tell the child’s story due to fragmented services, and travels).
Step 6: Identifying any borderline, related, or contrary cases
Identifying borderline, related, or contrary cases aims to further clarify the concept of CCHC.
Borderline case: Gabriel, a 2-month-old infant, was born moderately preterm at 34 weeks of gestation. His birth weight was 2000g. After 4 weeks, he was fully ready to be discharged from the neonatal intensive care unit to finally go home. This became clear to his care team when he showed that he was able to breathe without any support. Gabriel was able to maintain a stable body temperature. He did not have signs of infection. He kept gaining weight steadily. He was bottle-fed. His uncles and aunts participated in his feeding sessions. Everyone lived within a 5-kilometer distance from the large teaching children’s hospital in question. They were able to visit easily. At the time of the discharge to home, contrary to most parents of preterm infants, they did not feel apprehensive. Their son was physiologically stable. Gabriel had a smooth transition to a safe home where his loving parents were ready to take care of him. Thus, this was not a particularly complex case.
This borderline case possesses most, but not all, of the attributes of CCHC, as determined in Step 4. It is missing the breadth of conditions, namely the resulting multiple care needs, as there were no long-term implications, and the importance of developmental age. Although he was born prematurely, Gabriel is considered "mildly premature" on the spectrum of prematurity, from mild (33-36 completed weeks of gestation) to moderate (28-32 completed weeks of gestation) to extreme (< 28 completed weeks of gestation). He did not have any complication besides prematurity. By two months postpartum, Gabriel had enough time to “catch up” on any growth delay.
Related case: Paula, an 11-year-old girl, has allergies that can have moderate complications, such as sinusitis and eczema. Although potentially complex, these complications are not severe enough to cause an anaphylactic shock. Paula’s condition can be easily managed by avoiding the non-common allergy trigger, although this may not be always possible. There is no comorbidity. Despite the potential severity, Paula’s life is not in danger. However, her family gets worried as they live on a farm in a remote small rural community, lacking access to a family physician or nurse practitioner. This requires long distance travels for a consultation, which may be challenging in the winter.
This related case shares some of the defining attributes identified in Step 4, namely the varying extent of severity, although not to the point of an anaphylactic shock, and the need for services across settings, although only because of a lack of services and a complex geography. This case is missing the breadth of care needs and severity.
Contrary case: Maya, a 5-year-old child, from a small village suffered from norovirus-like symptoms. Norovirus is the most common form of foodborne illness in the world. Maya had a fever higher than 38.9 C (102 F). She became more irritable than usual. She had diarrhea and showed signs of dehydration. The virus has spread to others in her community. Thus, it was not very difficult for the family physician to diagnose it. The case was clearly not complicated or long-term. No specific medication was needed, as antibiotics are not effective against viruses. The physician explained to Maya’s parents that antibiotics’ overuse is problematic, contributing to antibiotic-resistant strains of bacteria. After 24 hours, Maya was back to her normal self.
This contrary case does not possess any of the defining attributes of CCHC. Clearly, Maya’s health condition was acute, neither complex nor comorbid, and did not require medication. Her parents were not distressed, especially where her diagnosis was confirmed fast and they quickly saw signs of improvement.
Step 7: Identifying any antecedents and consequences
Antecedents are the concept precursors whereas consequences are the concept outcomes.
Antecedents: CCHC have one/more chronic physical, mental, developmental, and behavioural conditions. Antecedents refer to this broad range of conditions and, by extension, to risk factors. An example may be the combination of genes and environmental factors in juvenile arthritis.
Consequences: CCHC require multiple services, including health, psychosocial, educational, and counseling ones. Care is provided by many clinicians, including pediatricians, other physicians, nurses, physiotherapists, psychologists, and social workers, among others. There may be system consequences (i.e. fragmented services), affecting the quality of life not only of CCHC but also of their family and care team.
Step 8: Defining empirical referents
This last step consists of identifying the empirical referents of the defining attributes of a concept, which describes its practical expression. The empirical referents were as follows: In general, CCHC had chronic conditions that required complex care, showed high morbidity and possibly mortality, whilst experiencing increased healthcare system use . It may be straightforward to recognize a child with complex-to-very-complex conditions [11, 31]. However, identifying CCHC with less complexity becomes complicated because: (1) stakeholders define CCHC differently; (2) it is often harder to capture individual characteristics with population data sources than in one-on-one encounters; and (3) contrary to adults, CCHC often have a spectrum of heterogeneous conditions. Perhaps like adults, some CCHC may have a condition that becomes complex only when comorbid.