Peer Review #2 of "Atrial fibrillation and psychological factors: a systematic review (v0.2)"

Abstract

Background. Psychological factors have been suggested to have an influence in Atrial Fibrillation (AF) onset, progression, severity and outcomes, but their role is unclear and mainly focused on anxiety and depression. Methods. A systematic electronic search had been conducted to identify studies exploring different psychological factors in AF. The search retrieved 832 articles that were reviewed according to inclusion criteria: observational study with a control/comparison group; use of standardized and validated instruments for psychological assessment. Results were summarized qualitatively and quantitatively by effect size measure (Cohen's d and its 95% confidence interval). Cochrane Collaboration guidelines and the PRISMA Statement were adopted. Results. Eight studies were included in the systematic review. Depression was the most studied construct/ but only one study showed a clear link with AF. The remaining studies showed small and non-significant (95% CI,-0.25-1.00) differences between AF and controls, no differences in frequency of depression history (95% CI,-0.14-0.22) or in case frequency (95% CI,-0.50-0.04). Miscellaneous results were found as far as anxiety: AF patients showed higher levels when compared to healthy subjects (95% CI, 2.05-2.95), but findings were inconsistent when compared to other heart diseases. Considering personality and life-events preceding AF, we respectively found a large (95% CI, 1.87-2.49) and a moderate to large effect (95% CI, 0.48-0.98). Discussion. The small number of studies does not allow to draw clear-cut conclusions on the involvement of psychological factors in AF. Promising lines of research are related to personality and adverse life-events, and to the increase of longitudinal design studies. Some methodological problems could be overcome by including clinical psychologists in the implementation of research protocols.