Nearly 67 percent of people with diabetes in China have difficulty keeping their blood glucose within safe levels because of widespread "clinical inertia" - a reluctance to prescribe combination drug therapies that have proved effective in other countries - according to a new study.

Backed by pharmaceutical giant MSD, the study tracked more than 5,000 patients and 237 clinical research centers for almost a year. It is thought to be the largest study ever conducted in China on the treatment of Type 2 diabetes.

The findings were published in the first issue of Science China Life Sciences, an academic journal of the Chinese Academy of Sciences and the National Natural Science Foundation of China.

Research and clinical practice overseas has shown that a combination of the drugs metformin and sitagliptin is effective and safe. Other drugs may also be added for a triple effect.

But clinical inertia in China has undermined effective treatment, according to Wang Jianping, who led the study. Wang is director of diabetes care research at the Third Affiliated Hospital of Sun Yat-Sen University in Guangzhou, Guangdong province.

Many Chinese physicians do not prescribe combination therapies in a timely manner, which leads to patients having excessively high blood glucose levels over a long period, he said. Poor control over time can lead to health problems such as heart disease, as well as damage to the eyes, kidneys or nerves.

Doctors "are reluctant to prescribe combination therapies, largely due to a lack of clinical evidence and treatment consensus" in China, Wang said.

Mu Yiming, a senior diabetes specialist who was part of the study team, said the findings could help bridge the knowledge gap and help develop clinical evidence in China supporting combination drug treatments.

In addition, he said, "We're working closely to integrate the findings into the latest version of the national treatment guideline, which is due very soon".

Xing Xiaoyan, head of endocrinology at China-Japan Friendship Hospital, also stressed the importance of patient education. "It's hard to change behavior, and some patients tend to reject combination drug therapy, citing potential adverse reactions," Xing said.

She said the cost of drugs was a concern for many patients, but the government is helping.

"We've seen the government cover more diabetes treatments under public health insurance," she said.

According to the National Health and Family Planning Commission, China has about 113 million adults with Type 2 diabetes, roughly 25 percent of the global total.

Experts estimate that more than 493 million Chinese are prediabetic, which means their blood glucose levels are too high but not high enough for a diabetes diagnosis.

[email protected]