Date Published: October 15, 2018
Publisher: Public Library of Science
Author(s): Margreet S. H. Wortman, Joran Lokkerbol, Johannes C. van der Wouden, Bart Visser, Henriëtte E. van der Horst, Tim C. olde Hartman, Stefan K. Lhachimi.
In primary and secondary care medically unexplained symptoms (MUS) or functional somatic syndromes (FSS) constitute a major burden for patients and society with high healthcare costs and societal costs. Objectives were to provide an overview of the evidence regarding the cost-effectiveness of interventions for MUS or FSS, and to assess the quality of these studies.
We searched the databases PubMed, PsycINFO, the National Health Service Economic Evaluation Database (NHS-EED) and the CEA registry to conduct a systematic review. Articles with full economic evaluations on interventions focusing on adult patients with undifferentiated MUS or fibromyalgia (FM), irritable bowel syndrome (IBS) and chronic fatigue syndrome (CFS), with no restrictions on comparators, published until 15 June 2018, were included. We excluded preventive interventions. Two reviewers independently extracted study characteristics and cost-effectiveness data and used the Consensus on Health Economic Criteria Checklist to appraise the methodological quality.
A total of 39 studies out of 1,613 articles met the inclusion criteria. Twenty-two studies reported costs per quality-adjusted life year (QALY) gained and cost-utility analyses (CUAs). In 13 CUAs the intervention conditions dominated the control conditions or had an incremental cost-effectiveness ratio below the willingness-to-pay threshold of € 50,000 per QALY, meaning that the interventions were (on average) cost-effective in comparison with the control condition. Group interventions focusing on MUS (n = 3) or FM (n = 4) might be more cost-effective than individual interventions. The included studies were heterogeneous with regard to the included patients, interventions, study design, and outcomes.
This review provides an overview of 39 included studies of interventions for patients with MUS and FSS and the methodological quality of these studies. Considering the limited comparability due to the heterogeneity of the studies, group interventions might be more cost-effective than individual interventions.
Study methods were documented in an international prospective register of systematic reviews (PROSPERO) protocol, registration number: CRD42017060424.
Patients with medically unexplained symptoms (MUS, i.e. physical symptoms for which no pathological cause can be found after adequate physical examination) are highly prevalent in primary and secondary care in all medical settings [1,2]. The classification of these physical symptoms is problematic as numerous overlapping diagnoses and syndrome labels show . Almost each medical specialty has defined its own syndrome(s) based on symptoms that relate to their organ of interest . Psychiatry uses the designation somatic symptom disorder, while most medical specialties have patients with clusters of MUS within so called ‘functional somatic syndromes’ (FSS)  e.g. fibromyalgia (FM) , irritable bowel syndrome (IBS) , chronic fatigue syndrome (CFS) , chronic benign pain syndrome and multiple chemical sensitivity (MCS) [4,8]. The most well-known FSS are FM, IBS, and CFS  and most primary care physicians and researchers are familiar with the umbrella term MUS .
The methods and reporting of this systematic review are in concordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (S1 Table) . Prior to the start of article inclusion, we documented study methods in an international prospective register of systematic reviews (PROSPERO) protocol (S1 Text), registration number CRD42017060424.
The current review provides an overview of 39 studies of interventions for patients with MUS, FM, IBS and CFS and the methodological quality assessment of these studies. In 13 out of 22 studies the intervention condition dominated the control conditions, meaning that the interventions were (on average) cost-effective in comparison with the control conditions. Considering the limited comparability due to the heterogeneity of the studies, the group interventions might be more cost-effective than individual interventions.