Evaluation of ‘implications for research’ sections in systematic reviews of interventions in advanced cancer patients – a meta-research study

Abstract

Background Implications for research (IfR) sections are an important part of systematic reviews (SRs) in healthcare. The PRISMA 2020 statement recommends discussion of the implications of the results for practice, while Cochrane Reviews require an IfR section. However, it is unclear to what extent systematic reviews discuss IfR and if this section is useful. We aimed i) to assess whether systematic reviews include an IfR section and ii) to evaluate which elements informed reporting of IfR. Methods We conducted a meta-research study based on SRs of interventions in advanced cancer patients from a previous project (CRD42019134904). We assessed if the following predefined IfR variables were referred to in the included SRs: patients, intervention, control, outcome, study design (PICOS); Grading of Recommendations, Assessment, Development and Evaluation (GRADE) domains: risk of bias, inconsistency, indirectness, imprecision, publication bias. Data were independently extracted by three reviewers after piloting the data extraction form. Discrepancies were resolved in weekly in-depth discussions. Results We included 261 SRs. The majority evaluated a pharmacological intervention (244, 93.5%); twenty-nine were Cochrane Reviews (11.1%). Four out of five SRs included an IfR section (210, 80.5%). PICOS elements commonly addressed in IfR sections were ‘intervention’ (121, 57.6%), ‘patient‘ (113, 53.8%) and ‘study design’ (107, 51.0%). The most frequent PICOS combinations were ‘patient and intervention‘ (71, 33.8%) and ‘patient, intervention and study design‘ (34, 16.2%). GRADE domains were rarely used for informing IfR recommendations: ‘risk of bias‘ (2, 1.0%), and ‘imprecision‘ (1, 0.5%), ‘inconsistency‘ (1, 0.5%). Additional factors informing IfR recommendations were considerations on cost effectiveness (9, 4.3%), reporting standards (4, 1.9%), and individual patient data meta-analysis (4, 1.9%). Conclusion Although four out of five systematic reviews of our sample included an IfR section, these were mostly considering only selected PICOS elements and GRADE domains were used rarely to guide future research recommendations. In the absence of established reporting standards, we propose more comprehensive and structured IfR sections in SRs informed by PICOS elements and GRADE domains. We suggest further empirical and theoretical work to eventually develop guidance on what IfR elements to consider and how to report IfR in SRs of interventions.