Aim: Hyperglycemia is associated with increased risk of microvascular complications in patients with type 2 diabetes (T2DM). The aim of the present study is to investigate whether reduction of the levels of HbA1c by tight glycemic control (GC) decreases the rate of microvascular complications and improves the neurological measures in T2DM.

Methods: Detailed clinical, neurological examinations including corneal confocal microscopy (CCM), were performed in 141 patients with poorly controlled type 2 diabetes (mean age 53, Duration diabetes: 9 years) at the baseline and 60 age-matched control subjects and followed-up with GC for 4 years. Nephropathy and Retinopathy also assessed. Patients were stratified according to mean HbA1c level during follow-up.

Results: At baseline CCM showed significant nerve fiber damage in all patients compared to controls. Despite strict GC and improvement in mean HbA1c by around 2.8%, overall the cumulative incidence of neuropathy increased from 17.7% at baseline to 21.3% and retinopathy increased from 21.3% to 35.5%, however the cumulative incidence of nephropathy reduced from 37.6% to 22%. Tight GC was effective in improving Neuropathy only in those with very poor Control at the Baseline. The interval changes in HbA1c levels were correlated with the interval changes in CNF measures and neurophysiological tests. The results showed one percent reduction in HbA1c levels per year significantly improved CNF measures and neurophysiological dysfunctions. Based on the results of this study, for improving neuropathy, only HbA1c close to 6.5% is effective for improvement in structure and function of the corneal nerves.

Conclusion: This study showed that the GC was just improved nephropathy among microvascular complications. Glucose control did only improve neurophysiological and corneal nerve measurements when near-normoglycemia was reached. Despite tight GC, the retinopathy progressed in patients with type 2 diabetes at this cohort.


M. Tavakoli: None. F. Ishibashi: None.

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