Very low-calorie diet leading to weight loss can induce remission of type 2 diabetes in the primary care setting
EBM Focus - Volume 12, Issue 51
- Surgery-induced weight loss has been associated with diabetes remission, but evidence for diet-based weight loss in the primary care setting is limited.
- In the DiRECT cluster-randomized trial, 40 primary care centers with 306 adults were randomized to an intensive diet-based weight management program vs. guideline-directed care alone for 12 months.
- Included patients were diagnosed with type 2 diabetes within the previous 6 years, did not require insulin therapy, and had a body mass index of 27-45 kg/m2. The weight management program had a goal of achieving ≥ 15 kg (33 lbs) weight loss and consisted of total diet replacement with a low energy formula for 3-5 months followed by structured food reintroduction and monthly visits for weight maintenance.
- Diabetes remission (glycemic control without antidiabetic drugs) was achieved in 46% of patients with the intensive diet vs. 4% with guideline-directed care alone (p < 0.0001, NNT 3). Remission was highly correlated with weight loss in an analysis of all patients.
Dietary management may help lower HbA1c levels in patients with type 2 diabetes and overweight or obesity, and surgery-induced weight loss is associated with sustained remission (Diabetes Care 2013, JAMA 2014). Recent theories of type 2 diabetes pathophysiology suggest that dietary management leading to weight loss might also achieve remission (Diabetologia 2017), but evidence is limited. The DiRECT trial randomized 49 primary care centers in Scotland and England to treat patients with an intensive diet-based weight management program with discontinuation of antidiabetic and antihypertensive medications vs. guideline-directed care alone for 12 months. The 306 included patients were aged 20-65 years, diagnosed with type 2 diabetes within the previous 6 years (mean 3 years), and had a body mass index of 27-45 kg/m2. Patients requiring insulin therapy were excluded, but 76% were taking antidiabetic drugs. The intensive diet had a goal of achieving and maintaining weight loss ≥ 15 kg (33 lbs) and consisted of total diet replacement with a low energy formula (825-853 kcal/day) for 3-5 months followed by patient-specific structured food reintroduction for 2-8 weeks and monthly visits thereafter. Antidiabetic and antihypertensive drugs were reintroduced if necessary. Diabetes remission was assessed at 12 months and was defined as HbA1c levels < 6.5% after > 2 months without antidiabetic drugs.
Diabetes remission was achieved in 46% of patients with the intensive diet vs. 4% with guideline-directed care alone (p < 0.0001, NNT 3). The intensive diet group also had higher rates of no antidiabetic drug use (in 74% vs. 18%, p < 0.0001, NNT 2) and weight loss ≥ 15 kg (33 lbs) (in 24% vs. 0%, p < 0.0001, NNT 5). In an analysis of all patients, increased weight loss was associated with an increased likelihood of diabetes remission, with remission in 0% of patients who did not lose weight, 7% with weight loss 0-5 kg, 34% with weight loss 5-10 kg, 57% with weight loss 10-15 kg, and 86% with weight loss ≥ 15 kg (p < 0.0001 for trend). In analyses of patients in the intensive diet group, baseline use of ≥ 2 antidiabetic drugs and HbA1c levels ≥ 8% were each associated with a lower likelihood of remission, and age ≥ 55 years old was associated with an increased likelihood. Factors that were not associated with remission include diabetes duration, weight, and sex.
The DiRECT cluster-randomized trial demonstrated that an intensive diet leading to weight loss in the primary care setting can induce diabetes remission at 12 months in adults with overweight or obesity and type 2 diabetes not requiring insulin therapy. The effect is dramatic and highlights the importance of diet and weight loss in these patients, but several important points should be considered. First, diabetes and obesity are chronic conditions in most patients, and sustained weight loss is uncommon; longer-term assessments are needed. Second, the feasibility of the intense and highly structured diet-based weight management program is unclear: even with the support available to patients in this trial, 21% of patients who started the program withdrew (all were included in the intention-to-treat analysis), and patient-specific strategies for weight maintenance were not described. Third, the importance of actual sustained weight loss should not be underestimated: remission was highly correlated with weight loss in an analysis of all patients, and patients who did not lose weight did not achieve remission. Finally, the beneficial effects observed in this trial may apply mostly to patients with less severe disease: patients with diabetes for > 6 years or requiring insulin therapy were excluded and patients taking ≥ 2 antidiabetic medications or with HbA1c levels > 8% at baseline were less likely to achieve remission. Nevertheless, this trial reinforces the recommendation that weight loss should be a first-line approach for managing type 2 diabetes in patients with overweight or obesity and demonstrates that an intensive diet leading to sustained weight loss can achieve remission in the primary care setting.
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