New Data Show Early and Intensive Glycemic Control Mitigates Long-Term Nerve and Eye Damage

An observational study involving more than 172,000 patients with newly diagnosed type 2 diabetes (T2D) revealed that the risks of developing retinopathy and neuropathy are lowest when hemoglobin A_1c levels are maintained within a nondiabetic range of less than 6.5%. These findings, published in the Journal of Diabetes and its Complications, suggest that the risk for these microvascular outcomes increases progressively as blood glucose levels rise, peaking significantly when A_1c exceeds 9.6%.¹

For pharmacists on the front lines of diabetes management, this data provides a clear mandate for early and intensive glycemic control to mitigate long-term damage to the nerves and eyes.¹

“Contemporary clinical guidelines are advocating for a less glucocentric, individualized approach to diabetes management, emphasizing multifactorial risk reduction and the utilization of novel therapies with demonstrated efficacy independent of glucose-lowering,” the study authors said.¹

The study’s findings, conducted in the United Kingdom, emphasize a legacy effect, where early glycemic control from the point of diagnosis plays a definitive role in preventing future complications. Although current clinical guidelines often recommend a target A_1c range between 6.5% and 7.5% to balance microvascular protection with the risk of hypoglycemia, this research indicates that the eyes and nerves benefit most from the lower end of that spectrum. Interestingly, the study noted a J-shaped association specifically for nephropathy, where risks increased at both extremes of A_1c, likely due to hypoglycemia-induced renal injury at very low levels. However, this trend was not observed for retinopathy or neuropathy, which showed a more direct, linear escalation of risk as glucose levels climbed.^1,2

The clinical reality for many patients is that these complications often begin silently, with up to 50% of peripheral neuropathy cases being asymptomatic until significant damage has occurred. Pharmacists play a vital role in screening and counseling, as the American Diabetes Association’s (ADA) 2025 Standards of Care recommend that patients with T2D receive a comprehensive eye exam and a neuropathy assessment at the time of their initial diagnosis.²

Recognizing early symptoms is critical, as the involvement of small nerve fibers often manifests as burning pain or tingling, while large-fiber damage can lead to a loss of protective sensation, placing patients at high risk for foot ulcers and eventual amputation.²

Further context for pharmacists is provided by cross-sectional research showing that these microvascular complications are deeply interconnected through shared pathological mechanisms like oxidative stress and chronic inflammation. Evidence suggests that retinal findings, such as diabetic macular edema, can serve as visible clinical markers for systemic damage elsewhere in the body.³

For instance, a significant inverse correlation exists between the severity of retinopathy and nerve conduction quality, as measured by sural sensory nerve action potential amplitude. Patients with macular edema were found to be four times more likely to have impaired nerve conduction, suggesting that a patient presenting with advanced eye disease is almost certainly experiencing concurrent systemic microvascular decline.³

Pharmacists must also remain vigilant regarding the pharmacological nuances of treatment intensification. Although the goal is to lower A_1c, the ADA warns that rapid reductions in glucose, particularly through the use of intensive therapies like glucagon-like peptide-1 receptor agonists, can sometimes lead to an initial, transient worsening of retinopathy. This necessitates close monitoring of a patient's retinal status whenever their glucose-lowering regimen is significantly escalated.²

For the management of existing neuropathic pain, the latest standards recommend initial treatments with gabapentinoids, serotonin-norepinephrine reuptake inhibitors, or tricyclic antidepressants and strongly advising against the use of opioids due to their lack of long-term efficacy and high potential for harm.²

Ultimately, the data suggests that age and comorbidities must be factored into every treatment plan. The UK study found that younger individuals under the age of 60 years appeared more susceptible to retinopathy as their A_1c levels increased compared to older patients, perhaps due to a longer duration of exposure to hyperglycemia over their lifetime. By integrating these insights, pharmacists can move beyond a one-size-fits-all approach, instead focusing on personalized risk reduction that prioritizes the legacy of early, tight control to preserve vision and nerve function for the long term.¹

“Our results found that using antihypertensive drugs was associated with decreased risks of retinopathy compared to no use of antihypertensive drugs in all HbA_1c levels except less than 48.0 mmol/mmol (<6.5%), therefore, more studies are needed to solve this controversy,” the study authors said.¹

READ MORE: Diabetes Resource Center

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REFERENCES

1. Aldafas R, Vinogradova Y, Crabtree TSJ, Gordon J, Idris I. The long-term impact of early HbA1c control on nephropathy, neuropathy, and retinopathy in type 2 diabetes: Findings from a large UK observational study. J Diabetes Complications. Published online February 25, 2026. doi:10.1016/j.jdiacomp.2026.109292

2. American Diabetes Association Professional Practice Committee. 12. Retinopathy, Neuropathy, and Foot Care: Standards of Care in Diabetes-2025. Diabetes Care. 2025;48(1 Suppl 1):S252-S265. doi:10.2337/dc25-S012

3. Roostaei S, Ashraf A, Fard MV, Johari M. Interrelationship of diabetic neuropathy, retinopathy and nephropathy in type 2 diabetes mellitus: a cross-sectional analysis. BMC Ophthalmol. 2025;25(1):604. Published 2025 Oct 29. doi:10.1186/s12886-025-04470-5