Reappraisal of the efficacy of intensive glycaemic control on microvascular complications in patients with type 2 diabetes: A meta-analysis of randomised control-trials

OBJECTIVE

To re-assess the effect of tight glycaemic control on diabetic microvascular complications.

METHOD

Meta-analysis and trial sequential analyses of randomised trials included in Hemmingsen et al that specifically assessed glycaemic control with a specific HbA_1c level targeted in the intervention group, and compared intensive glycaemic control versus standard glycaemic control.

RESULTS

Seven clinical trials that randomised 28,614 participants with type 2 diabetes (15,269 to intensive control and 13,345 to conventional control), including 3 sub-studies, were included. Strict control of blood glucose levels is associated with a reduction of retinopathy progression (RR=0.77, 95% CI: 0.66-0.89, I²=33%), incidence or progression of macular oedema (RR=0.66, 95% CI: 0.40-0.99, I²=0%), number of photocoagulations (RR=0.84, 95% CI: 0.73-0.97, I²=0%), risk of microalbuminuria (RR=0.76, 95% CI: 0.64-0.9, I²=76%) and risk of "macroalbuminuria or proteinuria" (RR=0.68, 95% CI: 0.55-0.85, I²=36%).

CONCLUSION

This meta-analysis has shown that a tight control of blood glucose levels is associated with a decrease of specific microvascular complication of diabetes: photocoagulation, progression of diabetic retinopathy, incidence or progression of macular oedema, risk of microalbuminuria and risk of macroalbuminuria or proteinuria. Regarding all the other outcomes (vision loss, surgery of cataract, proliferative or non-proliferative retinopathy, death related to kidney disease, development of kidney disease, doubling of serum creatinine, neuropathy), no significant result was found.

Potential diabetes overtreatment and risk of adverse events among older adults in Ontario: a population-based study

AIMS/HYPOTHESIS

More than 25% of older adults (age ≥75 years) have diabetes and may be at risk of adverse events related to treatment. The aim of this study was to assess the prevalence of intensive glycaemic control in this group, potential overtreatment among older adults and the impact of overtreatment on the risk of serious events.

METHODS

We conducted a retrospective, population-based cohort study of community-dwelling older adults in Ontario using administrative data. Participants were ≥75 years of age with diagnosed diabetes treated with at least one anti-hyperglycaemic agent between 2014 and 2015. Individuals were categorised as having intensive or conservative glycaemic control (HbA_1c <53 mmol/mol [<7%] or 54-69 mmol/mol [7.1-8.5%], respectively), and as undergoing treatment with high-risk (i.e. insulin, sulfonylureas) or low-risk (other) agents. We measured the composite risk of emergency department visits, hospitalisations, or death within 30 days of reaching intensive glycaemic control with high-risk agents.

RESULTS

Among 108,620 older adults with diagnosed diabetes in Ontario, the mean (± SD) age was 80.6 (±4.5) years, 49.7% were female, and mean (± SD) diabetes duration was 13.7 (±6.3) years. Overall, 61% of individuals were treated to intensive glycaemic control and 21.6% were treated to intensive control using high-risk agents. Using inverse probability treatment weighting with propensity scores, intensive control with high-risk agents was associated with nearly 50% increased risk of the composite outcome compared with conservative glycaemic control with low-risk agents (RR 1.49, 95% CI 1.08, 2.05).

CONCLUSIONS/INTERPRETATION

Our findings underscore the need to re-evaluate glycaemic targets in older adults and to reconsider the use of anti-hyperglycaemic medications that may lead to hypoglycaemia, especially in setting of intensive glycaemic control.

Long-term follow-up of intensive glycaemic control on renal outcomes in the Veterans Affairs Diabetes Trial (VADT)

AIMS/HYPOTHESIS

We conducted an analysis of data collected during the Veterans Affairs Diabetes Trial (VADT) and the follow-up study (VADT-F) to determine whether intensive (INT) compared with standard (STD) glycaemic control during the VADT resulted in better long-term kidney outcomes.

METHODS

VADT randomly assigned 1791 veterans from 20 Veterans Affairs (VA) medical centres who had type 2 diabetes mellitus and a mean HbA_1c of 9.4 ± 2% (79.2 mmol/mol) at baseline to receive either INT or STD glucose control for a median of 5.6 years (randomisation December 2000 to May 2003; intervention ending in May 2008). After the trial, participants received routine care through their own physicians within the VA. This is an interim analysis of the VADT-F (June 2008 to December 2013). We collected data using VA and National databases and report renal outcomes based on serum creatinine, eGFR and urine albumin to creatinine ratio (ACR) in 1033 people who provided informed consent to participate in the VADT-F.

RESULTS

By the end of the VADT-F, significantly more people who received INT treatment during the VADT maintained an eGFR >60 ml min^-1 1.73 m^-2 (OR 1.34 [95% CI 1.05, 1.71], p = 0.02). This benefit was most evident in those who were classified as at moderate risk (INT vs STD, RR 1.3, p = 0.03) or high risk (RR 2.3, p = 0.04) of chronic kidney disease on the Kidney Disease Improving Global Outcomes (KDIGO-CKD) at the beginning of VADT. At the end of VADT-F, significantly more people from the INT group improved to a low KDIGO risk category (RR 6.1, p = 0.002). During the VADT-F there were no significant differences between INT and STD for average HbA_1c, blood pressure or lipid levels.

CONCLUSIONS/INTERPRETATION

After just over 11 years of follow-up, there was a 34% greater odds of maintaining an eGFR of >60 ml min^-1 1.73 m^-2 and of improving the KDIGO category in individuals with type 2 diabetes who had received INT for a median of 5.6 years. VADT clinical trials.gov number: NCT 00032487.