Effect of renin-angiotensin-aldosterone system blockade in adults with diabetes mellitus and advanced chronic kidney disease not on dialysis: a systematic review and meta-analysis

The presumed superiority of renin-angiotensin-aldosterone system (RAAS)-blocking agents over other antihypertensive agents in patients with diabetes to delay development of end-stage kidney disease (ESKD) has recently been challenged. In addition, there is ongoing uncertainty whether RAAS-blocking agents reduce mortality and/or delay ESKD in patients with diabetes and chronic kidney disease (CKD) stages 3-5. In this subgroup, there might be an expedited need for renal replacement therapy (RRT) when RAAS-blocking agents are used. We conducted a meta-analysis of randomized controlled trials (RCTs) of at least 6-months duration in adult patients with diabetes who also have non-dialysis CKD stages 3-5. RCTs comparing single RAAS-blocking agents to placebo or alternative antihypertensive agents were included. Outcomes of interest were allcause mortality, cardiovascular morbidity, progression of renal function, ESKD and adverse events. A total of nine trials (n = 9797 participants with CKD stages 3-5) fit our inclusion criteria. There was no difference between the RAAS group and control group regarding all-cause mortality {relative risk [RR] = 0.97 [95% confidence interval (CI) 0.85-1.10]}, cardiovascular mortality [RR = 1.03 (95% CI 0.75-1.41)] and adverse events [RR = 1.05 (95% CI 0.89-1.25)]. There was a trend for a favourable effect for non-fatal cardiovascular events [RR = 0.90 (95% CI 0.81-1.00)] and a lower risk of the composite endpoint need for RRT/doubling of serum creatinine [RR = 0.81 (95% CI 0.70-0.92)] in the RAAS-blocking agents group versus the control group. We found evidence that in patients with diabetes mellitus and CKD stages 3-5, treatment with RAAS-blocking agents did not result in a clear survival advantage. The effect on renal outcomes did depend on the selected outcome measure. However, we did not find evidence that the use of RAAS-blocking agents expedited the need for RRT in patients with CKD stages 3-5.