Low calorie vs low carbohydrate for T2D remission (DiRECT vs Virta)

Introduction

My recent soups and shakes note generated much interest and a couple of requests to compare the results from DiRECT with those from Virta. Very low calorie vs very low carbohydrate – both have results at two years, so how do they compare?

We’ve covered the DiRECT study here (Ref 1) and here (Ref 2). The headlines were: randomisation (by practice) for 49 practices in Scotland and the Tyneside region of England; 149 people followed in each of the intervention and control groups; primary outcomes were weight loss of 15kg or more and remission of type 2 diabetes (T2D) which was defined as HbA1c of less than 6.5% (<48 mmol/mol) after at least 2 months off all anti-diabetic medications, between baseline and 12 months. (HbA1c is a measure of glucose levels over the past three months).

We need to get similar headlines from the Virta study and then compare results.

The Virta study

Virta utilised a virtual medicine treatment (remote continuous care) described as an open-label, non-randomized, continuous care intervention (CCI) promoting nutritional ketosis; compared to usual care (UC) offered to patients in the same community. Results were then presented after two years. (Open-label means that information is not withheld from trial participants; the trial isn’t blinded – i.e. participants and researchers know who is in which group.) Primary outcomes were HbA1c, weight, and medication use.

Adults diagnosed with T2D were recruited via clinical referrals, local adverts, and word of mouth in Lafayette, Indiana, USA and the surrounding region from August 2015 through March 2016. The study enrolled 349 adults following expressions of interest and after excluding volunteers who didn’t meet the inclusion criteria (pregnancy/planned pregnancy and cancer treatment in the past 5 years were examples of exclusion criteria). Participants self-selected to join either the CCI group (262 people) or the UC group (87 people), the latter primarily through the local specialty diabetes clinic. There were 218 participants still enrolled in the CCI at 1 year. Both DiRECT and Virta used Intention-To-Treat analysis, but the Virta papers also reported the per protocol results, which is best practice (Note 3).

CCI group participants were given a cellular-connected body weight scale, a finger-stick blood glucose and ketone meter and a blood pressure machine if hypertension was diagnosed. Education and communication with the remote care team was provided for the CCI group, whereas the UC group maintain usual care via the diabetes specialty clinic. The CCI care team included a coach and medical practitioner/physician for advice and medication management. Social support was provided via an online peer community. The CCI enabled the remote care team to monitor weight and blood beta-hydroxybutyrate (BHB – a marker of ketosis) daily, and blood glucose levels one to three times a day.