A review looked at studies of patients with type 1 or 2 diabetes that compared intensive glycemic control (targeting HbA1c <7% or fasting glucose level <120 mg/dL [6.67 mmol/L]) with standard control (target of HbA1c ≥7%, fasting glucose level ≥120 mg/dL [6.67 mmol/L], or author-defined) for six months or longer. The review found no significant differences in rates of end-stage kidney disease (ESKD) or cardiovascular (CV) events between the groups.
The study was published in the Cochrane Library on June 8. The following commentary by Indranil Dasgupta, MBBS, MD, DM, and Ajay K. Singh, MBBS, MBA, was published in the ACP Journal Club section of the Oct. 17 Annals of Internal Medicine.
Diabetes is a major risk factor for CV events and death and a leading cause of ESKD. The review by Ruospo and colleagues suggests that treating diabetes with strict glycemic control does not reduce mortality or CV risk, or slow progression of kidney disease. This begs the question of whether strict glycemic control for preventing any complications is warranted.
The findings of the review are limited by high or unclear risk for bias in several domains of most trials, low or very low certainty of evidence for many outcomes, and inadequate reporting of potentially harmful consequences of intensive glycemic control. Only about 30% of trials enrolled patients with type 1 diabetes, reducing the generalizability of the results. Further, results may not apply to newer agents for type 2 diabetes, including sodium–glucose cotransporter-2 inhibitors and glucagon-like peptide-1 agonists, which seem to have CV and renal benefits beyond their glycemic effect.
Although clinicians may consider whether it would be better to focus on intensive blood pressure (BP) control rather than tight glycemic control in patients with diabetes, more trial data are needed to reach such a conclusion. However, meta-analyses of BP control in diabetes have shown similar results in patients with baseline systolic BP <140 mm Hg: Treatment had no observed benefits and increased risk for CV death.
Given the rarity of most key outcomes, especially ESKD, a large 5- to 10-year trial is needed. Until then, these results will inform discussions between patients with diabetes and health professionals regarding treatment targets.