Chronic functional constipation (CFC) in childhood is a common complaint characterised by a reduced frequency or difficulty in passing a stool. It is a highly prevalent and costly condition affecting up to one in three children at any one time [1]. The annual constipation treatment costs to the NHS (England) in 2018-2019 are conservatively estimated at £168 million [1], in addition to notable indirect social costs such as missed days at school. Identifying clinically effective treatments that optimise cost-effectiveness is key to ensuring a sustainable health service, yet we have little insight to whether interventions currently being delivered to children with CFC are effective or cost-effective. A recent systematic review evaluated the cost effectiveness of treatment for chronic constipation focussing only on full economic evaluations in adult and children. Han et al. (2018) identified ten studies that reported economic evidence in adults only; no evidence for children or special populations (e.g., children and young people with additional support needs) was found. Here we report the economic findings from a recent systematic review that was conducted as part of a larger Health Technology Assessment project [2]. Building on the earlier published work by Han (2018) [3], we have broadened the scope of this systematic review to identify all types of economic studies of interventions used to manage CFC in childhood.

Study design: A systematic review. Selection criteria were predefined and published in PROSPERO (CRD42019159008).

Methods: 
Search: Systematic searches of 10 electronic databases plus supplementary searches of grey literature and relevant websites. Backward and forward citation tracking was used to identify further related, relevant studies. Searches were conducted from October 2011 to Feb 2020. In addition to the systematic searches outlined [2], the reviewers also took the decision to update the searches based on Han (2018) [3]. 

Study selection: studies tagged as potentially having economic evidence in scoping review were carried through for more detailed data extraction. We included all types of studies which reported any evidence of cost, regardless of study design. 
Data extraction: a data extraction form was piloted, and data was extracted by one reviewer and cross-checked by a second reviewer. We extracted key information about the study (method, funder, conflicts of interest, design, study objectives), perspective (i.e. health society, society), additional study methods details (i.e. treatment setting, country of study population, study duration, follow-up period, inclusion/exclusion criteria), participants (i.e. target population, number and age of participants, number of participants completing the study), intervention characteristics, brief details of the comparator group and outcomes reported. We also extracted the following information related to the economic evidence within each study: economic question, type of economic study, costs (economic outcome measure, identification of costs, cost categories, cost values, source of the cost values) and benefits (identification of benefits, benefit categories, benefit values) and key economic findings. 

Coding and analysis: The type of economic study was coded as either a cost-consequence, cost effectiveness, cost-utility, cost-benefit, cost-analysis, unclear or unreported. These were then mapped by two independent reviewers to an intervention category based on the complexity of delivering the intervention and the providers of the intervention (see Figure 1). Synthesis: a narrative review of relevant studies was undertaken to arrive at overall conclusions regarding the state of knowledge of the cost-effectiveness of interventions for the UK.

Our systematic searches identified 32826 potential studies; 1747 full papers were retrieved; and 33 studies met the selection criteria. The majority of studies were conducted in the USA (n=10), UK (n=8) or were based on secondary data from more than one country (n=8). Of the 33 studies, 8 specifically aimed to evaluate economic evidence. The remaining studies employed a wide range of different study designs including systematic reviews / literature reviews (n=8), narrative / descriptive studies (n=5), cohort studies (n=4), quality improvement studies (n=2), randomised controlled trials (n=2); case vignettes (n=2), mixed methods (n=1) and a webpage (n=1). 

The majority of the studies were reported from a health perspective (n=20) and were conducted in a hospital setting (n=17) or a primary care / patient’s home / community setting (n=5). Interventions were diverse and included laxatives, physiotherapy, complementary therapies (e.g., abdominal massage, acupuncture), educational online training, multidisciplinary clinics, and sacral neuromodulation. Two studies specifically focussed on children with additional support needs.

Most of the included studies reported a cost-analysis (n=14) or cost-utility (n=9), although the reporting was frequently poor with limited details provided. The type of economic evidence mapped to the different intervention categories is presented in Figure 1. The most frequently reported economic evidence was reported in papers that mapped to more than one of the intervention categories, and the least frequently reported evidence was for interventions specifically delivered by continence teams or specialist services.

Relatively few studies have systematically explored the economic impact of constipation in children and young people. Less than a quarter of the studies specifically aimed to evaluate economic evidence. The majority of economic evidence identified within this review comes from studies which report cost analysis, with partially reported detail. Much of the existing evidence appears to rely heavily on the findings of a handful of studies that are more than a decade old.

This is the first systematic review to include all types of economic evidence of treatments used to manage constipation in children. We found a paucity of available economic data and what little evidence was available was frequently often out-of-date. Robust economic evidence for interventions is urgently required to keep pace with the increase in emerging treatments in children and young people with constipation and may serve as benchmark data for future work.

Bowel Interest Group (2020) Cost of constipation report. Third edition. https://bowelinterestgroup.co.uk/wp-content/uploads/2020/07/Cost-of-Constipation-2020.pdf
McClurg D, Hagen S, Elders A, Campbell P, Pollock A, Booth L, Mason H, Torrens C, Rayner J, Sutcliffe J, Jankulak K, Millington C, Ogden M, Smith D (2021) Strategies used for constipation in Children – Evidence Synthesis involving Stakeholders (SUCCESS). https://www.journalslibrary.nihr.ac.uk/programmes/hta/NIHR128470/#/
Han D, Iragorri N, Clement F, Lorenzetti D, Spackman (2018) Cost-effectiveness of treatments for Chronic Constipation: A systematic review. PharmacoEconomics 36: 435-449.