Abstract
BACKGROUND: Aggressive glycemic control has been hypothesized to prevent renal disease in patients with type 2 diabetes mellitus. A systematic review was conducted to summarize the benefits of intensive vs conventional glucose control on kidney-related outcomes for adults with type 2 diabetes. METHODS: Three databases were systematically searched (January 1, 1950, to December 31, 2010) with no language restrictions to identify randomized trials that compared surrogate renal end points (microalbuminuria and macroalbuminuria) and clinical renal end points (doubling of the serum creatinine level, end-stage renal disease [ESRD], and death from renal disease) in patients with type 2 diabetes receiving intensive glucose control vs those receiving conventional glucose control. RESULTS: We evaluated 7 trials involving 28 065 adults who were monitored for 2 to 15 years. Compared with conventional control, intensive glucose control reduced the risk for microalbuminuria (risk ratio, 0.86 [95% CI, 0.76-0.96]) and macroalbuminuria (0.74 [0.65-0.85]), but not doubling of the serum creatinine level (1.06 [0.92-1.22]), ESRD (0.69 [0.46-1.05]), or death from renal disease (0.99 [0.55-1.79]). Meta-regression revealed that larger differences in hemoglobin A1c between intensive and conventional therapy at the study level were associated with greater benefit for both microalbuminuria and macroalbuminuria. The pooled cumulative incidence of doubling of the serum creatinine level, ESRD, and death from renal disease was low (<4%, <1.5%, and <0.5%, respectively) compared with the surrogate renal end points of microalbuminuria (23%) and macroalbuminuria (5%). CONCLUSIONS: Intensive glucose control reduces the risk for microalbuminuria and macroalbuminuria, but evidence is lacking that intensive glycemic control reduces the risk for significant clinical renal outcomes, such as doubling of the serum creatinine level, ESRD, or death from renal disease during the years of follow-up of the trials.