Reversing type 2 diabetes is much harder than clinical trials suggest

People with type 2 diabetes who lose weight while taking part in clinical trials appear to be substantially more likely to reverse their condition than those who lose weight outside of such studies.

Treatments such as insulin injections can help people with type 2 diabetes maintain healthy blood sugar levels. However, those who are overweight or obese can sometimes reverse their condition if they lose weight.

In reality, fewer than 10 per cent of people with type 2 diabetes who lose weight outside of such trials actually do this, even when followed over several years, says Hongjiang Wu at the Chinese University of Hong Kong. In trials, that figure can get close to 90 per cent.

Such a discrepancy may be due to the support and various interventions that often come with taking part in clinical trials, as well as definitions of what it means to reverse type 2 diabetes sometimes varying, he says.

To better understand this, Wu and his colleagues studied more than 37,000 people in Hong Kong – roughly half of them women – aged 18 to 75, who were diagnosed with type 2 diabetes between 2000 and 2017.

Each participant was followed for an average of just under eight years, with the researchers looking at how their weight may have changed in the first year after their diagnosis, as well as whether they reversed their condition at any time during the study period.

The researchers measured the participants’ glycated haemoglobin (HbA1c) levels, which reflects their blood glucose state over several months. Reversing type 2 diabetes, also known as remission, is generally defined as HbA1c being less than 6.5 per cent when measured at least three months after stopping treatments. The researchers were looking for these levels to occur in two consecutive tests carried out six months apart.

The team only measured the participants’ weight one year after they were diagnosed, by which time 2 per cent had gone into remission and half had gained weight, says Wu.

By the end of the study, 6 per cent had gone into remission at some point, says Wu. Of these people, around two-thirds required diabetes drugs to control their condition again within three years.

But by only recording the participants’ weight one year after they were diagnosed, the researchers don’t know whether they went on to gain weight or if other factors may have resulted in some of them coming out of remission, such as gaining weight specifically around their waist or accumulating fat in certain internal organs.

In contrast, one small clinical trial found that up to 86 per cent of people with type 2 diabetes who lost at least 15 kilogrammes went into remission within a year. People in studies like these often benefit from professional dietary management, physical exercise programmes, moral support, regular monitoring, feedback, reminders and encouragement, says Wu.

But even people who take part in the control arm of some clinical trials, who may not be put on intensive weight loss programmes, have better remission rates than those seen in Wu’s team’s study.

That may be because, outside of clinical trials, doctors are often more hesitant to recommend that people with type 2 diabetes stop their treatments, he says. It is also probably related to differences in how remission is defined, as trials often require only one healthy HbA1c reading, says Wu.

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