Systematic review of economic evaluations investigating education, exercise, and dietary weight management to manage hip and knee osteoarthritis: protocol

Osteoarthritis (OA) is a major cause of disability [1]. International guidelines recommend education, exercise, and dietary weight management (if appropriate) as the core treatments for OA before progressing to pharmacological and surgical interventions [2]. However, low uptake of core treatments persists [3]. To improve uptake, various OA management programs (OAMPs) using core treatments have been developed, evaluated, and shown to be clinically effective, but consensus has not been reached on the cost-effectiveness of these programs [4]. Evaluating cost-effectiveness of OAMPs has been identified as a research priority by a group of international OA researchers [5]. A cost-effective intervention means the treatment provides more health benefit at an additional cost but within the decisions-makers’ willingness to pay for those health benefits [6]. Cost-effectiveness is an important consideration for the implementation of OAMPs in budget-constrained health care systems [6].

A 2012 systematic review found sparse literature and recommended more studies that evaluate the cost-effectiveness of nonsurgical and nonpharmacological interventions in OA [7]. Authors found eleven publications showing mixed results and a high a risk of bias due to poor quality methodology [7]. To improve study quality, the authors recommended standardized methodologies such as generic health outcome measures, capturing all disease-related costs and comparing the intervention to usual care [7]. Since 2012, methodological recommendations [8‐11] and reporting criteria [12, 13] for economic evaluations have been produced. To identify research gaps, a systematic review identifying the current body of empirical knowledge is warranted.

Economic evaluations inform decision-makers about the consequences of resource allocation decisions by comparing the cost and health outcomes of two or more interventions [6]. Clinical trials can be used as a vehicle to conduct economic evaluations by collecting patient-level costs and health outcomes [6]. Alternatively, the relevant literature can be synthesized using decision-analytic modeling techniques to produce economic estimates [6]. Methodological differences between model and trial-based economic evaluations limit their comparability so authors have argued to systematically review these distinct methodologies separately [14]. Different quality assessment tools have also been published to evaluate trial and model-based economic evaluations separately [15]. Lastly, trial-based economic evaluations are more common in the research field evaluating nonpharmacological and nonsurgical treatment of OA [9]. For these reasons our systematic review will focus on economic studies where primary data was collected. We will synthesize and assess quality of economic evaluations investigating the cost-effectiveness of core treatments (education, exercise, and dietary weight management) for the management of hip and/or knee OA.

This review protocol is being reported in accordance with the reporting guidance provided in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) statement (see checklist in Additional file 1) [16]. The protocol has been registered within the International Prospective Register of Systematic Reviews (PROSPERO) database (registration number CRD42020155964).

To support the implementation of OAMPs, we will provide a current overview of published literature evaluating the cost-effectiveness of core treatments to manage hip and knee OA. Synthesizing economic evaluations for core treatments will describe progress in the research field and enable analysts to assess transferability of the results to local decision problems. This work may identify current gaps in the literature which will provide direction for future research. Subgroup analysis will attempt to identify common characteristics between studies, health systems, and models of care which affect the cost-effectiveness results for core treatments. Lastly, this review will allow the authors to explore the tradeoffs between resource allocation and health outcomes for the management of OA using core treatments.

There is substantial difference between the methodologies to conduct economic evaluations using modeling or trial-based economic evaluations [6]. As recommended by previous authors, this systematic review will focus on one methodology [14]. Trial-based economic evaluations are more popular in nonsurgical and nonpharmacological economic research [9]. This literature synthesis will also enable future transferability assessments [23]. Our analysis will differ from Pinto et al. as they used the Quality of Health Economic Analyses instrument although it is recommended as a quality assessment tool for model-based economic evaluations [7, 8, 15]. The CHEC list is the preferred quality assessment tool for systematic reviews of economic evaluations alongside clinical trials [8, 15]. A systematic review of economic evaluation quality assessment tools found the CHEC list had strong criterion validity and inter-rater reliability [15]. The publication of reporting standards and methodological guidelines in the past decade has progressed in the health economics research field [9‐13]. This review will attempt to understand whether methodological quality has improved in economic evaluations of OA interventions since reporting guidelines were published.

Ample research shows the clinical effectiveness of core treatments for OA [2, 24, 25]. However, the cost-effectiveness of these interventions remains unclear [7]. Cost-effectiveness research plays an important role for health services decision-making by describing the tradeoffs between resources consumed for health outcomes gained. In a budget-constrained health care system, economic evaluations are used to inform decision-making for the adoption of new treatments and technologies [6]. As research shifts towards the implementation of OAMPs, a current systematic review of economic evaluations is warranted. This systematic review will synthesize the economic literature, explore gaps in the research field, and support future research of recommended treatments for OA.