Heart rate variability in the prediction of survival in patients with cancer: A systematic review and meta-analysis

Purpose: Although the predictive value of vagal nerve activity, indexed by heart rate variability (HRV), has been confirmed in a variety of diseases, its value in the prediction of survival in cancer patients still remains controversial. The aim of this meta-analysis was to evaluate the predictive value of HRV in cancer patients in an evidence based manner. Methods: A systematic review and meta-analysis was conducted through a comprehensive search of the PubMed, EMBASE and the Cochrane Central Library databases for all studies regarding HRV, vagal nerve activity and cancer. Pooled data of overall survival was analyzed. Results: Six studies with 1286 patients were included in our meta analysis. Analysis of the pooled data revealed that overall survival was significantly longer in the higher HRV group than in the lower HRV group (HR 0.70, 95% CI [0.60, 0.82]; P < 0.001, 12 = 27%). Conclusion: The current evidence indicates a predictive value of HRV in the survival of patients with cancer and higher vagal nerve activity might predict longer survival, but the results should be applied with caution considering the heterogeneity between included studies. (C) 2016 Published by Elsevier Inc.