Psychological interventions for distress in adults undergoing haematopoietic stem cell transplantation: a systematic review with meta-analysis

Objectives: To investigate the characteristics, methodology, quality, and efficacy of psychological interventions for distress in adult patients undergoing haematopoietic stem cell transplantation (HSCT). Methods: A systematic review of relevant studies was conducted using six databases with supplementary hand searching. Included studies employed an experimental or quasi-experimental design, interventions included at least one psychological component, and outcomes involved psychological distress in affective terms. Data were abstracted, and study quality was assessed using Cochrane Foundation criteria amended to include confounder and common factors control. Data were examined and synthesised using a narrative approach and meta-analysis. Results: Eleven articles for nine interventions met the inclusion criteria out of 11,741 abstracts. The studies varied in quality, general, intervention, and methodological characteristics while findings were mixed. Interventions tended to show better efficacy when incorporating a major psychological component involving cognitive behavioural or emotional processing methods with substantial interventionist input. However, this was also associated with methodological limitations and threats to internal validity such as poor confounder and common factors control. A meta-analysis yielded a small but significant pooled effect size estimate in favour of interventions with inconsequential heterogeneity. Risk of bias remained a concern. Conclusions: Psychological interventions may provide some benefit in alleviating distress in HSCT but conclusions remain tentative in light of methodological limitations and risk of bias. Further research is needed to evidence the individual contribution of intervention components and mechanism of change together with improving intervention efficiency and methodological quality