The Korean Diabetes Association (KDA) has removed metformin as the preferred first-line treatment for type 2 diabetes in its newly revised 2025 Clinical Practice Guidelines for Diabetes, citing a lack of evidence showing the drug’s superiority over newer therapies and the need for more individualized treatment approaches.

At a press briefing held on Wednesday ahead of the association’s upcoming spring scientific conference, Professor Lee Byung-wan, KDA Clinical Practice Guideline Committee Director and professor of endocrinology at Severance Hospital, announced the key updates to the guidelines.

Under the previous 2023 edition, metformin was recommended as the first-line pharmacological treatment for type 2 diabetes in the absence of contraindications or adverse effects. However, following a recent meta-analysis, the guidelines committee concluded there was insufficient evidence to maintain this recommendation.

"We found no proof that metformin is superior to other therapies," Lee said. "Furthermore, the characteristics of Korean patients, particularly younger adults with anabolic states and older adults with catabolic states, suggest that a one-size-fits-all approach with metformin is no longer appropriate."

KDA Chairman Cha Bong-soo also highlighted concerns that reimbursement policies requiring metformin as a first-line drug had distorted real-world prescribing practices.

"Doctors often feel compelled to prescribe metformin just to meet insurance requirements before considering newer, potentially more suitable drugs," he said. "We want to change this mindset."

Lower blood pressure targets and new pediatric treatment recommendations

The revised guidelines also lower the target blood pressure for diabetic patients from below 140/90 mmHg to below 130/80 mmHg. The change reflects consensus reached with other Korean medical societies, including the Korean Society of Hypertension and the Korean Society of Cardiology.

For pediatric patients with type 2 diabetes, the recommended glycated hemoglobin (HbA1c) target has been tightened from below 7.0 percent to below 6.5 percent. The guidelines now recommend considering pharmacological treatment immediately upon diagnosis rather than waiting for lifestyle interventions to fail, with options including metformin monotherapy, insulin monotherapy, or combination therapy.

In cases where HbA1c exceeds 8.5 percent at diagnosis, the guidelines advise initiating insulin treatment without delay.

Continuous glucose monitoring and obesity surgery guidance expanded

The KDA has strengthened its recommendations for continuous glucose monitoring (CGM), emphasizing that use of the technology should be accompanied by professional education for optimal outcomes. Digital education platforms, such as e-learning, were also recognized as effective self-management tools and have been incorporated into the guidelines.

Also, for patients with a body mass index (BMI) of 30 kg/m² or higher who have not achieved weight loss or glycemic control through non-surgical means, metabolic surgery is now recommended as a treatment option.

Toward personalized treatment and international harmonization

The ninth edition of the guidelines adopts a flexible treatment algorithm based on three key axes: blood glucose levels, cardiovascular and renal risk, and pancreatic beta-cell failure or catabolic state.

The algorithm includes both drug classes and specific agents to accommodate newer therapies not yet widely reimbursed in Korea.

Lee stressed that the updates were developed based on both global evidence and Korean data, balancing procedural transparency, safety, and clinical practicality.

"Our aim is to raise the quality of diabetes care in Korea and align our practices with international standards," he said, adding that an English version of the guidelines will also be published for broader dissemination.

The full details of the 2025 Clinical Practice Guidelines for Diabetes will be officially presented at the KDA’s 38th Spring Scientific Conference and the 7th Korea-Japan Diabetes Forum, to be held from May 8 to 10 at the HICO Convention Center in Gyeongju.