Adding non-randomized and non-controlled studies to an existing review on the effectiveness of chronic disease management programs for asthmatic patients

Article type
Authors
Arditi C1, Burnand B1, Peytremann-Bridevaux I1
1Cochrane Switzerland and Institute of Social and Preventive Medicine, Lausanne University Hospital, Switzerland
Abstract
Background: Systematic reviews (SRs) of interventions usually include randomized controlled trials (RCTs) only. However, complex interventions such as chronic disease management (CDM) programs are often evaluated using study designs other than RCTs, mainly for reasons of feasibility. Considering non-randomized and non-controlled (NRNC) studies in an SR on CDM programs could be informative both in terms of intervention context and effectiveness.
Objectives: To assess if and how setting, population, intervention characteristics, and results varied when adding NRNC studies to an ongoing Cochrane SR with the Effective Practice and Organization of Care Review Group.
Methods: All NRNC studies identified as evaluating CDM programs in asthmatic adults, but excluded from the Cochrane SR because of the design, were considered in this review, in addition to the already included studies. Two review authors independently extracted data and assessed the methodological quality using the Cochrane risk of bias tool, with additional questions for non-controlled studies. We compared study and intervention characteristics, as well as effectiveness, by study design.
Results: Thirty-seven studies were added to the 20 studies already included in the original SR. The added studies were of poor methodological quality (e.g. no statistical adjustments for confounding in controlled before-after studies). Study and intervention characteristics of the NRNC studies differed from those in the original SR (Table 1). For instance, CDM programs were implemented in a larger variety of countries, included larger numbers of patients, and reported process and healthcare use outcomes more often. Effectiveness also varied according to study design (Table 2). Overall, the proportion of outcomes that improved in response to CDM was higher in the NRNC studies compared with the studies from the original SR.
Conclusions: While NRNC studies provide results from interventions in real-life settings that may be valuable to policymakers and other stakeholders implementing CDM programs, the methodological quality of the studies is poor, limiting the validity and the interpretation of their results.