A systematic review and meta-analysis of glycemic control for the prevention of diabetic foot syndrome

Objective The objective of this review was to synthesize the available randomized controlled trials (RCTs) estimating the relative efficacy and safety of intensive vs less intensive glycemic control in preventing diabetic foot syndrome. Methods We used the umbrella design (systematic review of systematic reviews) to identify eligible RCTs. Two reviewers determined RCT eligibility and extracted descriptive, methodologic, and diabetic foot outcome data. Random-effects meta-analysis was used to pool outcome data across studies, and the I² statistic was used to quantify heterogeneity. Results Nine RCTs enrolling 10,897 patients with type 2 diabetes were included and deemed to be at moderate risk of bias. Compared with less intensive glycemic control, intensive control (hemoglobin A_1c, 6%-7.5%) was associated with a significant decrease in risk of amputation (relative risk [RR], 0.65; 95% confidence interval [CI], 0.45-0.94; I² = 0%). Intensive control was significantly associated with slower decline in sensory vibration threshold (mean difference, -8.27; 95% CI, -9.75 to -6.79). There was no effect on other neuropathic changes (RR, 0.89; 95% CI, 0.75-1.05; I² = 32%) or ischemic changes (RR, 0.92; 95% CI, 0.67-1.26; I² = 0%). The quality of evidence is likely moderate. Conclusions Compared with less intensive glycemic control therapy, intensive control may decrease the risk of amputation in patients with diabetic foot syndrome. The reported risk reduction is likely overestimated because the trials were open and the decision to proceed with amputation could be influenced by glycemic control.