This Web Annex provides detailed information on the processes, procedures and methods for developing Guidelines on the management of chronic pain in children. These guidelines were developed according to World Health Organization (WHO) guidance on guideline development: WHO handbook for guideline development (2 nd edition, 2014). 1 The main steps for developing WHO guidelines include: 1) establishment of the general scope of the guideline and development of the key questions; 2) identification of contributors to the guideline process: 3) performance of systematic reviews of the evidence to address the key questions; 4) assessment of the quality (certainty) of the body of evidence for important and critical outcomes; 5) formulation of recommendations and drafting of the guideline document; 6) review and approval by the Guideline Development Group (GDG); 7) external peer review; 7) review and approval by WHO's internal quality assurance processes; and 8) publication and dissemination.

# SCOPE AND KEY QUESTIONS a) Drafting of the key question
In response to Member States' needs, the WHO Steering Group initially proposed a draft scope for these guidelines, focused on nonpharmacological, pharmacological and combination therapy for the management of chronic pain associated with a medical illness or condition (i.e. secondary pain) in children. In order to further focus the content of the guidelines and to guide the systematic reviews of the evidence, the WHO Steering Group drafted a single key question in PICO (population, intervention, comparator, outcome) format:
Among children with chronic pain associated with a medical illness or condition ("secondary chronic pain"), would giving nonpharmacological, pharmacological or a combination of management interventions compared to placebo produce significant pain reduction and other critical outcomes?

# b) Public comment and stakeholder input
This key question and the planned scope of the guidelines were posted for public comment on the WHO website from 20 December 2019 to 13 January 2020. Interested persons and entities could provide written comments and also read them at a public hearing held via video conference on 16 January 2020. In addition to the public posting, United Nations Member States, governmental and nongovernmental organizations, research and academic institutions, philanthropic foundations, and private sector entities with an interest or stake in the management of chronic pain in children were invited to provide comments and participate in the hearing. Advanced registration was required in order to optimally manage the forum and ensure wide participation.
Registrants were invited to deliver a two-minute statement and submit a written template-based statement with a 200-word limit. There was no opportunity for discussion or debate.

# PROCESSES AND METHODS FOR GUIDELINE DEVELOPMENT
There were 93 registrants for the public hearing, including 16 journalists or students who requested to listen but did not make comments. Of the remaining 77 registrants, 49 provided oral and written statements on the scope and/or key question. The hearing lasted approximately three hours.

# c) Finalization of the scope and key questions
The GDG met on 24 January 2020 to discuss the statements from the public hearing. Upon review and discussion of the statements, the GDG revised the scope and key question by: 1) expanding the population to include children with primary chronic pain; 2) redefining the subgroups of the population by age, use of palliative care and intellectual disability; 3) defining the nonpharmacological interventions as psychological and physical management of pain; and 4) adding outcomes to the key question for further consideration.
The GDG agreed upon the following key question:
Among children with chronic pain, would giving pharmacological, psychological, physical interventions or a combination of these, compared to placebo or active comparators, produce significant improvement in the pain experience and other critical outcomes?

# d) Prioritization of outcomes
In order to identify those outcomes most important for decision-making, the GDG prioritized a list of potentially important outcomes. In this exercise, administered by the delegated WHO responsible technical officers, GDG members scored ten outcomes in terms of their importance from 1 to 9 (where 7-9 indicated that the outcome was critical for a decision, 4-6 indicated that it was important and 1-3 indicated that it was not important). All mean scores were tallied and ranked. From this exercise, seven critical and three important outcomes were identified. Any adverse event reported in primary studies was considered to be a critical outcome.
Details of the finalized key question and outcomes are presented in Table 1.

# TABLE 1. DETAILS OF THE FINAL KEY QUESTION
Population n Children (0-19 years) with chronic pain (pain that persists or recurs for longer than 3 months)
This population will include children with chronic primary pain and those with any medical illness or condition where pain is a symptom or where pain is related to an illness or the treatment of an illness (i.e. chronic secondary pain). This is an approach to care for persons, families and caregivers who are facing a life-limiting illness or where a person is near the end of life. The goal of palliative care is to improve the quality of life of patients and their families. This approach focuses on the prevention and relief of suffering by means of early identification, assessment and treatment of pain as well as by addressing the physical, psychosocial and spiritual needs of the individual and their family and caregivers.
Intellectual disability is characterized by impairment of skills across multiple developmental areas such as cognitive functioning and adaptive behaviour. WHO. Mental disorders, 28 November 2019  (, accessed 5 December 2020).
A broad range of contributors helped to develop this guideline: each type of contributor had a well-defined role and was subject to specific WHO policies and procedures. This approach helps to ensure the effectiveness and objectivity of all contributors, while bringing together a pool of contributors with diverse experiences, expertise and perspectives. A summary of each type of contributor and their roles and assessment process is provided in Table 2.

# a) WHO Steering Group
The WHO Steering Group managed the administrative aspects of the guideline development process and provided technical and procedural support for the GDG throughout the process. The Steering Group drafted the scope and key questions of the guideline, identified and approved the members of the GDG, collected and assessed the declarations of interest of external contributors (with support from the Office of Compliance, Risk Management and Ethics), and finalized the planning proposal. The Steering Group also oversaw the process for selecting contractors for performing the evidence reviews, drafted the null recommendations, finalized the draft guidelines for review by the GDG and External Review Group (ERG) and managed the guideline publication and dissemination processes. In addition, the Steering Group is responsible for monitoring new information after the guideline is published, assessing the need for updating, and for responding to end-user feedback and requests.

# b) Guideline Development Group
The GDG was composed of 22 external experts with a range of technical skills, experiences and perspectives, and with wide geographic representation and gender balance. The GDG consisted of technical experts in pain management in children and various other stakeholders whose expertise included human rights law, bioethics, social policy, care in humanitarian settings, lived experiences with chronic pain and guideline methods. Each GDG member represented themselves as individuals: they did not represent any Member State, governmental or nongovernmental entity, or institution. The importance of this fact was made clear to each GDG member at the start of their participation, and reiterated at the beginning of each GDG meeting.
The GDG was responsible for formulating the recommendations in the guideline and for the final guideline content. Specifically, the GDG worked with the WHO Steering Group to define the scope and key questions and prioritize the outcomes, reviewed the systematic reviews, formulated the recommendations and corresponding rationale statements, and reviewed and approved the final guideline document.
GDG members were identified and selected via a clearly defined and transparent process. A list of potential members was identified from a "Call for experts" for both the pain management guideline and a concurrently planned document entitled Access to Controlled Medicines. This call was published on the WHO website from 29 August to 24 October 2019, and was also shared through other WHO public web pages (e.g. the Maternal Newborn Child and Adolescent Health website), social media (Twitter and LinkedIn) and emailed to various palliative care associations, childhood cancer communities and paediatric and anaesthesiology societies across the globe. No members of the GDG for the 2012 WHO guidelines on the pharmacological treatment of persisting pain in children with medical illnesses participated in developing this guideline.
There were 108 eligible individuals from the call for experts (there was one ineligible submission from a WHO staff member). Of these submissions, 40 were primarily interested in joining the GDG for the guideline on the management of pain in children, while an additional 13 individuals requested to work on either this guideline or the Access to Controlled Medicines document, but preferred this guideline.
Of the 53 individuals who indicated an interest in the guideline on the management of chronic pain in children, 49 were technical experts in the field of clinical treatment of chronic pain in children, or academic researchers in this area or in addiction research. One applicant anticipated being an end-user of the guideline, and three others had technical expertise in related areas (health economics, bioethics, equity or human rights). The vast majority of the submissions worked in the WHO Region of the Americas (19), the European Region (14) and the African Region (12).
In order to include additional perspectives, particularly from regions and with expertise that were lacking or underrepresented in the responses to the open call, the WHO Steering Group sought the names of additional individuals from staff in relevant WHO departments and from WHO expert advisory panels. An additional nine GDG members were identified using this approach.
The GDG held two virtual meetings: the first on 24 January 2020, when the group finalized and approved the general scope, key questions including outcomes and target audience of the guideline. In a subsequent survey, the GDG members prioritized the potential outcomes of interest. The GDG met for a second time on 14-18 September 2020 when members examined the Grading of Recommendation Assessment, Development and Evaluation (GRADE) evidence profiles; interpreted the evidence on benefits and harms and other considerations; and formulated recommendations, guiding principles, best practice statements and a list of research gaps.

# c) Guideline methodologist
A guideline methodologist was hired as a consultant to support the WHO Steering Group and the GDG throughout the development process. The methodologist is an expert in the processes and methods for evidence synthesis and critical appraisal, GRADE and in the formulation of evidence-based recommendations.

# d) Systematic review teams
Two systematic review teams were contracted by the WHO Steering Group to provide input into the key questions, perform systematic reviews, develop GRADE evidence profiles including an assessment of the quality (certainty) of the body of evidence, and to present the review findings to the GDG. The teams contracted to perform these reviews were identified through an open bidding process after WHO issued a request for proposals on the United Nations Global Marketplace (/). Proposals were assessed by a panel of WHO staff based on a weighted set of technical and cost criteria. The first review focused on effectiveness and safety of physical, psychological and pharmacological interventions for the management of chronic pain in children. The second review was a qualitative evidence synthesis of the sociocultural acceptability of the included interventions and the values and preferences of patients, caregivers, and providers in relation to these interventions.

# e) Other technical experts
The responsible WHO technical officers hired a consultant economist to perform a rapid systematic review of existing economic evaluations of the interventions examined in this guideline, and to provide cost data on the various treatments in diverse settings.

# f) External review group
The ERG provided input into the final content and presentation of the guidelines. These individuals have an interest and expertise in the management of chronic pain in children. They were identified by the delegated WHO technical officers with input from the Steering Group as persons who could provide varied perspectives and expertise to complement those of the GDG. Their specific role was to review the draft final guideline and provide comments, particularly related to errors or missing data, and clarification on issues related to implementation, dissemination, ethics, regulation and monitoring. ERG members attended the September 2020 GDG meeting at which recommendations were formulated and were encouraged to participate in the discussions. They did not, however, have a direct role in formulating or approving the recommendations.

# g) Meeting observers
Representatives of several paediatric, anaesthesiology, palliative care and pain groups or organizations were invited to attend the September 2020 GDG meeting as observers. These organizations were potential end-users and implementers of the guidelines, or represented various target audiences. Only one invitee accepted. Their role at the meeting was to observe, and to speak only at the explicit request of the meeting cochairs. They did not participate in the formulation of recommendations.

# h) Funders
This guideline was funded by WHO; there were no external sources of funding.

# MANAGEMENT OF CONTRIBUTORS a) Declaration of interests
All potential contributors to the development of the guideline, including both individuals external to the Organization and employees of WHO, completed a standard WHO declaration of interests form. 3

# b) Assessment and management of conflicts of interest
Assessment of the declarations of interest and other information gathered on potential contributors was made according to the principles, processes and procedures laid out in the WHO Guidelines for Declaration of Interests (WHO Experts). 3 Each type of contributor was subject to specific rules and procedures (Table 2).

# Guideline Development Group
Prior to issuing an invitation to join the GDG, potential members were vetted according to WHO's standard policies and procedures for collaborations with external experts. 3 In addition to the standard declaration of interests (DOI) form for external experts, 3 potential members submitted a detailed curriculum vitae.
In the interests of transparency and to identify any additional relevant information or conflicts of interest, each prospective GDG member provided a brief biography which was published for public notice and comment from 24 December 2019 to 10 February 2020 on the website of the Department of Maternal, Newborn, Child, Adolescent Health and Ageing. No comments were received.
The WHO Steering Group performed an internet search for additional information on prospective members, including sources of research funding, published declarations of interests, board membership and other affiliations, and publications, including public statements, commentaries and opinion pieces related to the management of pain in children.
All information gathered on each potential GDG member was carefully examined by the delegated technical officers, in consultation with the Steering Group, the Director of the Department of Maternal, Newborn, Child, Adolescent Health and Ageing, and WHO's Office of Compliance, Risk Management and Ethics. Financial, intellectual and other interests disclosed by and identified about potential GDG members were assessed for any potential or perceived risk that they might impinge on the potential member's impartiality.
The standards applied and process followed in this assessment are described in the WHO Guidelines for Declaration of Interests (WHO Experts). 3 Interests were assessed as insignificant or minimal if they were considered unlikely to affect or reasonably be perceived to affect the individual's judgement on the management of chronic pain in children. If an interest was deemed to be potentially significant, the following management options were considered: 1) conditional participation of the individual in the guideline development process; 2) partial exclusion; or 3) total exclusion.
Following satisfactory assessments in line with this vetting process, the WHO Steering Group offered formal invitations to individuals to join the GDG in January 2020. Four members were added in February 2020 to provide expertise in specific areas. At the time of the invitation, each member was asked to update their declaration of interests if there were any changes, and to sign the WHO Confidentiality undertaking. 3 None of the identified potential GDG members was assessed as having a significant conflict of interest. All appointed members were therefore permitted to participate fully in the guideline development process. The list of GDG members and a summary of their declarations of interest are found in Annex A of the main guideline document.
At the beginning of the two GDG meetings, all attendees including GDG members verbally declared any relevant interests, highlighting any updates.

# External Review Group
Potential members of the ERG underwent an evaluation process identical to that of the GDG. Their biographies were posted for public comment from 20 May to 17 June 2020. No comments were received and no conflicts of interest identified.
All contractors who contributed to the guideline completed the WHO declaration of interests (DOI) form. Any disclosed interests were assessed according to the WHO policy for conflicts of interest. 3 Contractors were not permitted to have any financial interests relevant to the subject of this guideline.

# Meeting observers
The single meeting observer completed the standard WHO declaration of interest form and was deemed to have no conflicts of interest. The observer identified her affiliation at the beginning of the GDG meeting.

# WHO staff
WHO staff are subject to the WHO Code of Ethics and Professional Conduct. 4 Senior technical staff, including the delegated technical officers and WHO Steering Group members, provide declarations of interests annually to the Office of Compliance, Risk Management and Ethics, which assesses and provides instructions for any necessary management plan. Other staff members working on guidelines completed the declaration of interest form at the beginning of the guideline development process. The delegated technical officers and members of the Steering Group did not disclose interests which were relevant to these guidelines.

# c) Leadership of the Guideline Development Group
Members of the GDG nominated and confirmed two co-chairs at the first GDG meeting on 24 January 2020. These individuals were selected for their experience in managing group processes, interpreting evidence and chairing WHO meetings that require building consensus among participants with diverse views. The role of the co-chairs was to serve as a liaison between the GDG and WHO Steering Group throughout the development process, to facilitate the presentation and sharing of information and discussions, and to guide the GDG in the consensus process to develop recommendations. While they were permitted to express their opinions at the meetings, their primary role was to facilitate consensus-building in the group. If consensus could not be reached and voting was necessary to finalize the recommendations, they had the right to vote but could not exercise veto or any other exceptional powers in the decision-making process.

# d) Group processes and decision-making
The principles and general procedures for decision-making for WHO guidelines are set out in the WHO Handbook for Guideline Development (2 nd edition, 2014). 1 All meeting attendees had clearly defined roles and the meeting co-chairs were responsible for seeing that these roles were adhered to. GDG members were solely responsible for finalizing and approving the recommendations and rationale statements, and had voting rights when consensus could not be achieved. The delegated WHO responsible technical officers helped to guide the meeting process, ensure that WHO policies and procedures were followed, and provided administrative support, as well as technical support upon request. ERG members and external technical experts could participate in the discussions on recommendations but could not participate in the consensus process when recommendations were finalized, and could not vote. The guideline methodologist guided the co-chairs and GDG in interpreting the evidence, understanding GRADE certainty-of-evidence assessments, translating evidence into recommendations and in optimal guideline processes and procedures.
WHO guideline recommendations are formulated by means of a process which is designed to achieve consensus among GDG members. Consensus is defined as the situation in which all GDG members can agree to, or "live with" the recommendation as formulated, including its general wording, direction and strength (strong or conditional). Consensus is still considered to have been achieved where there are minor disagreements concerning the wording of a recommendation or its rationale statement.
Specific rules for agreeing on recommendations and other decisions were established at the beginning of the September 2020 GDG meeting. In order for a recommendation to be finalized, at least two-thirds of the full complement of the GDG had to be in attendance. Deliberations among GDG members took place until consensus was reached, meaning that all members agreed to the final wording. If consensus could not be achieved, a vote was held. Voting was anonymized, took place online, and was organized and collated by the delegated WHO responsible technical officers. A decision threshold of 80% was set apriori for approval of any recommendation requiring a vote.

# e) Confidentiality
All persons who were not WHO employees and attended one or both GDG meetings signed the WHO standard Confidentiality Undertaking3 prior to the first meeting. The purpose of this form is to ensure that participants in the guideline development process uphold WHO's efforts to speak with a single voice when providing clear, evidencebased recommendations. Importantly, a pledge of confidentiality also helps to ensure that each GDG member and any other participant can speak freely at meetings. WHO staff are subject to confidentiality rules according to the WHO Code of Ethics and Professional Conduct. 4

# SYSTEMATIC REVIEWS AND EVIDENCE ASSESSMENT a) Scoping review
At the beginning of the guideline development process, the responsible technical officers performed a scoping review to identify existing systematic reviews addressing the key question. The following databases were searched: PROSPERO, Cochrane Library, Epistemonikos and Campbell Collaboration. None of the identified reviews was deemed to be sufficiently comprehensive or up to date to be used as the basis for formulating recommendations in these guidelines.
Commissioned systematic reviews WHO commissioned a Cochrane Task Force composed of members of the Cochrane Pain, Palliative and Supportive Care Group (PaPas), Cochrane Qualitative Implementation Methods Group (QIMG) and Cochrane Response to perform systematic reviews on the effectiveness, harms and acceptability of physical, psychological and pharmacological therapies for chronic pain in children.
WHO commissioned the Cochrane QIMG to perform a qualitative evidence synthesis of experiences with and sociocultural acceptability of physical, psychological and pharmacological interventions for the management of chronic pain in children, and the relative values placed on the benefits and harms of these interventions. This review examined the perspectives of patients, parents and caregivers, healthcare providers and other key stakeholders with respect to: 1) safety and efficacy of interventions used to manage pain in children; 2) dependence and misuse potential; and 3) the public health benefits and risks of different strategies to ensure appropriate access. Particular attention was given in this review to capturing a diversity of viewpoints relating to socioeconomic status, ethnicity, sociocultural factors, gender, religion and geographical region of residence.
All commissioned reviews adhered to Cochrane methods and standards as described in the Cochrane Handbook for Systematic Reviews of Interventions (2 nd edition). 5 The specific approaches and methods used are described in each systematic review. 6,7 c) Assessment of the certainty of the body of evidence for each outcome
The GRADE system was used to assess the certainty (quality) of the body of quantitative evidence for each critical and important outcome. The certainty of evidence for each outcome was rated as high, moderate, low or very low, based on a set of criteria including study limitations, inconsistency, imprecision, indirectness and publication bias. 8 The findings of the qualitative reviews were appraised using the GRADE Confidence in the Evidence from Reviews of Qualitative research (GRADE-CERQual) approach. 9 Overall confidence in the evidence from reviews of qualitative research was based on methodological limitations of the individual studies, adequacy of the data, coherence of the evidence and relevance of the individual studies to the review finding. These assessments of quantitative and qualitative evidence were presented in GRADE evidence profiles to the GDG for discussion and formulation of recommendations.

# FORMULATING RECOMMENDATIONS a) Evidence-to-decision frameworks
The GDG formulated recommendations at a virtual meeting on 15-18 September 2020. Facilitated by the two GDG co-chairs and assisted by the WHO Steering Group and the guideline methodologist, the GDG used a structured framework for decisionmaking. This was the GRADE evidence-to-decision (EtD) framework for public health interventions, 10 which includes the following considerations: priority of the problem, the balance of the benefit-s and harms of the intervention, certainty of evidence, value placed on outcomes by those impacted by recommendations, intervention impact on equity, resource implications, and intervention acceptability and feasibility.

# b) Process for formulating recommendations
The WHO Steering Group developed a set of "null recommendations", which included both "for" and against" options as a neutral starting point for GDG discussions at the 15-18 September 2020 meeting. The systematic review teams, working with the guideline methodologist and the WHO Steering Group, populated the EtD framework with data from the reviews and other sources. Systematic reviews, GRADE evidence profiles, populated EtD frameworks and the null recommendations were presented to the GDG prior to the meeting, and formed the basis for its discussions.

# c) Recommendations
The GDG formulated either a strong or conditional recommendation, for or against each intervention or group of interventions discussed on the basis of the evidence on benefits, harms and other considerations according to the EtD framework. A strong recommendation means the GDG was confident that the desirable effects of adherence to a recommendation outweighed the undesirable effects. Most informed patients would choose the recommended intervention and for policy-makers the recommendation could be adopted as a policy in most situations. On the other hand, a conditional recommendation means that the GDG concluded that the desirable effects of adherence to a recommendation probably outweighed the undesirable effects, but to a lesser degree of confidence. Patients' choices will then vary according to their values and preferences and shared-decision-making with their provider may be needed. Policymakers may require substantial debate and the involvement of many stakeholders to reach a decision.11
In addition to recommendations on interventions for the management of chronic pain in children, these guidelines present a set of guiding principles. These principles, composed and approved by the GDG, underpin all aspects of the management of chronic pain in children. Since these statements are based on human rights and ethics principles, they do not require a systematic review of research evidence on benefits and harms.
Another type of statement contained in this guideline is referred to as best practice statements. Likewise, being based on good clinical or public health practice and experience, these statements do not require a systematic review of the benefits and harms of an intervention. Best practice statements are generally not contested because not carrying them out would be either nonsensical or illogical.

# REVIEW AND APPROVAL
After the GDG meeting, the writer drafted the guidelines: once approved by the delegated WHO technical officers, the draft was circulated to the GDG for review and approval. The draft final guideline was also sent for peer review by the ERG. The role of peer review is to provide technical feedback, identify errors of fact, comment on clarity of language and provide considerations related to implementation, adaptation and contextual issues. Its role is not to change the recommendations already agreed by the GDG. However, if the peer reviewers identify major concerns, these can be referred back to the GDG for consideration. In the present case, this situation did not arise.
WHO has an internal approval and quality assurance process to ensure that all WHO publications, including guidelines, meet the highest international standards for quality, reporting and presentation. These guidelines were reviewed and approved by the WHO Guidelines Review Committee (GRC) and by the Deputy Director-General and Acting Executive Director, Universal Health Coverage/Life Course and the Chief Scientist.
The WHO Secretariat will continue to follow research development in pharmacological, physical and psychological management of chronic pain in children, particularly for questions in which the certainty (quality) of evidence was found to be low or very low.
If new evidence emerges or other important considerations arise which may impact the current recommendations, the Department of Maternal, Newborn, Child, Adolescent and Ageing will coordinate an update of these guidelines, following the procedures outlined in the WHO handbook for guideline development (2 nd edition). 1 Unless new evidence necessitates an earlier review, at five years from publication of these guidelines, the Department of Maternal, Newborn, Child and Adolescent Health and Ageing at the WHO headquarters in Geneva, Switzerland, along with its internal partners, will conduct systematic reviews of the relevant evidence and appraise the need for updating or revalidating the current guidelines. WHO will seek stakeholder input on the scope of the updated guideline, as new interventions and considerations emerge.    () Certainty of evidence applies to all studies combined; certainty was not assessed for the subgroup which combined CBT, ACT, BT and RT. Abbreviations: ACT, acceptance commitment therapy; BT, behavioural therapy; CBT, cognitive behavioural therapy; MD, mean difference; N, total number of study participants; RD, risk difference; RR, risk ratio; RT, relaxation therapy; SMD, standardized mean difference Effect sizes are presented as standardized mean difference (95% confidence interval) unless otherwise indicated.

# Very low
Health-related quality of life Post-treatment: Antidepressant vs placebo (amitriptyline) 1 study, N=33 One study reported the treatment group was more likely to improve quality of life from baseline, compared to placebo.

# Very low
Follow-up: Antidepressant vs placebo (amitriptyline) 1 study, N=33 One study reported the antidepressant group was more likely to improve quality of life from baseline, compared to placebo. One non-randomized study reported no differences between citalopram and placebo groups on activity participation, post-treatment.

# Very low

# Follow-up No studies ---
Patient global judgement Satisfaction with treatment, post-treatment 3 studies, N=695 One study reported a higher percentage of subjects treated with sumatriptan and naproxen versus placebo reported being satisfied/very satisfied for "how effective the medication is overall" and "overall satisfaction with medication" at 2 and 24 hours post-dose (unadjusted P .014). Two further studies comparing antidepressants (citalopram and amitriptyline) to placebo did not note any differences between groups in the ITT analyses.
Satisfaction with treatment, follow-up 1 study, N=115 One study reported no differences between children receiving antidepressants (citalopram) to placebo in the ITT analyses at follow-up (p = 0.491).

# Very low
Impression of change, post-treatment 1 study, N=104 One study reported patient global impression of change response was significantly improved with pregabalin versus placebo (p = 0.013), with 53.1% of subjects much improved or very much improved at endpoint with pregabalin, compared with 29.5% with placebo.

# Very low

# Impression of change, follow up No studies
Fatigue Post-treatment No studies

# Follow up
No studies () These outcomes were prioritized as "important outcomes"; the remainder were considered "critical outcomes". Abbreviations: AE, treatment-related adverse event; N, number of studies; RD difference; SMD, standardized mean difference; ITT, intention to treat

# Characteristic Findings, total body of evidence
No. studies/no. participants Fulfilled inclusion criteria: 74
Reviewed in detail: 33
Linkage to effectiveness review Linked to studies in quantitative review: 12
Examined an included intervention but not linked to a study in the effectiveness review: 6
Not linked to effectiveness review: 15 Funders Not stated: 22 (30%)
Charitable foundation: 13 (18%)
Psychological therapies 1. For ACT aimed at parents and their adolescent child, some parents accepted their role in addressing their own behaviour and thoughts, whereas others rejected this.
ACT Sweden (31) Low 2. Some adolescent children did not see the relevance of ACT for addressing pain and wanted a medical cure for their pain, not to live well with pain.
ACT Sweden (31) Low 3. For some parents and adolescent children, ACT was viewed as a last resort treatment, only to be pursued when a biomedical approach to explaining and treating pain had been unsuccessful. 31. Some HCPs including doctors and nurses expressed the fear that children might get addicted to opioids and fake reports of pain to receive opioids, and that opioids were more dangerous than the pain itself: this meant that pain went untreated and children suffered.

# None specificopioids
Thailand, Morocco (44, 48) Low 21. For children with cancer, parents demonstrated or stated their acceptance of opioid treatment: some Jordanian parents stated that their child's pain could and should be managed, including with analgesics such as opioids. Similarly, Cameroonian children aged 9-14 with cancer receiving palliative care in rural communities and their families welcomed provision of adequate pain medication, including opioids (oral morphine), which was provided for free. In Indonesia, parents administered opioids (morphine) to their child with cancer pain for palliative care under doctor's advice. In contrast, some HCPs in Morocco and Thailand believed that parents feared their children would become addicted to morphine and were likely to refuse it.. When assessing pain in Morocco, some HCPs recognized that they needed more training in assessing and managing children's pain and wanted tools/scales to measure pain for themselves and children. In some situations in Jordan, Morocco and Brazil, a crying child was identified as the most common pain cue/primary pain manifestation recognized by parents and HCPs. In Thailand and Brazil, HCPs stated that parents played a key role in communicating their child's pain to them, especially when a child had cognitive impairments, and that parents were often better at judging pain than HCPs because they know their own child. However, parents in Indonesia reported finding it difficult to judge if their child with cancer was in pain and the level of pain, unless the child told them. Some Jordanian parents believed that children with cancer should be responsible and express their pain, rather than be asked about their pain. WEB ANNEX I. Assessment of the quality/ confidence in the body of evidence

# SYSTEMATIC REVIEW OF ECONOMIC STUDIES: METHODS

# Effectiveness of pharmacotherapy
Studies were examined at the individual level only.

# WEB ANNEX K.

# EVIDENCE-TO-DECISION TABLES
The Guideline Development Group discussed each of the listed considerations and made a judgement in each case (highlighted). This process facilitated the formulation of the recommendations.

# A. PHYSICAL THERAPY