A new study published in Atherosclerosis investigated the efficacy and safety of combined renin-angiotensin-aldosterone system (RAAS) blockade in dialysis patients. This study was a systematic review and mediation analysis which conducted a comprehensive search in PubMed, EMBASE, Web of Science and Cochrane Library database through June 2017, to identify relevant studies. A total of 9 studies with 13,050 dialysis patients were included. It was observed that, when compared to single blockade, combined blockade significantly reduced all-cause mortality, whereas cardiovascular mortality remained unchanged. Combined blockade tended to increase odds of hypotension but not odds of hyperkalemia. Furthermore, mediation analysis indicated that hypotension might exert a suppression effect on the survival benefit of angiotensin-converting enzyme inhibitor plus angiotensin receptor blocker treatment on cardiovascular mortality. Thus, it was concluded that combined RAAS blockade might be a promising treatment in dialysis patients to further reduce mortality if blood pressure was well controlled.