Factors affecting the delivery of complex rehabilitation interventions in research with neurologically impaired adults: a systematic review

BACKGROUND: Rehabilitation research does not always improve patient outcomes because of difficulties implementing complex health interventions. Identifying barriers and facilitators to implementation fidelity is critical. Not reporting implementation issues wastes research resources and risks erroneously attributing effectiveness when interventions are not implemented as planned, particularly progressing from single to multicentre trials. The Consolidated Framework for Implementation Research (CFIR) and Conceptual Framework for Implementation Fidelity (CFIF) facilitate identification of barriers and facilitators. This review sought to identify barriers and facilitators (determinants) affecting implementation in trials of complex rehabilitation interventions for adults with long-term neurological conditions (LTNC) and describe implementation issues. METHODS: Implementation, complex health interventions and LTNC search terms were developed. Studies of all designs were eligible. Searches involved 11 databases, trial registries and citations. After screening titles and abstracts, two reviewers independently shortlisted studies. A third resolved discrepancies. One reviewer extracted data in two stages; 1) descriptive study data, 2) units of text describing determinants. Data were synthesised by (1) mapping determinants to CFIF and CFIR and (2) thematic analysis. RESULTS: Forty-three studies, from 7434 records, reported implementation determinants; 41 reported both barriers and facilitators. Most implied determinants but five used implementation theory to inform recording. More barriers than facilitators were mapped onto CFIF and CFIR constructs. “Patient needs and resources”, “readiness for implementation”, “knowledge and beliefs about the intervention”, “facilitation strategies”, “participant responsiveness” were the most frequently mapped constructs. Constructs relating to the quality of intervention delivery, organisational/contextual aspects and trial-related issues were rarely tapped. Thematic analysis revealed the most frequently reported determinants related to adherence, intervention perceptions and attrition. CONCLUSIONS: This review has described the barriers and facilitators identified in studies implementing complex interventions for people with LTNCs. Early adoption of implementation frameworks by trialists can simplify identification and reporting of factors affecting delivery of new complex rehabilitation interventions. It is vital to learn from previous experiences to prevent unnecessary repetitions of implementation failure at both trial and service provision levels. Reported facilitators can provide strategies for overcoming implementation issues. Reporting gaps may be due to the lack of standardised reporting methods, researcher ignorance and historical reporting requirements. SYSTEMIC REVIEW REGISTRATION: PROSPERO CRD42015020423 SUPPLEMENTARY INFORMATION: Supplementary information accompanies this paper at 10.1186/s13643-020-01508-1.