The quality of evidence is downgraded by study limitations (lack of blinding) and upgraded by large magnitude of effect.
Intensive weight management is recommended as therapy of choice as a non-pharmacological treatment for motivated patients.
A meta-analysis 2 assessing associations of structured exercise training in type 2 diabetes (T2D) included 47 RCTs with 8538 patients. Structured exercise decreased HbA1c (-0.67%, 95% CI -0.84% to -0.49%; 23 trials) compared with control. Declines in HbA1c compared with control were -0.73% (95% CI -1.06% to -0.40%) in structured aerobic exercise; -0.57% (95% CI -1.14% to -0.01%) in structured resistance training; and -0.51% (95% CI -0.79% to -0.23%) in both combined. Structured exercise durations of more than 150 minutes per week were associated with HbA1c reductions of 0.89%, while structured exercise durations of 150 minutes or less per week were associated with HbA1c reductions of 0.36%. Combined physical activity advice and dietary advice was associated with decreased HbA1c (-0.58%; 95% CI -0.74% to -0.43%) as compared with control.
In a open-label, cluster-randomised trial 1 49 primary care practices in Scotland and England were randomly assigned to provide either a weight management programme (intervention) or best-practice care by guidelines (control). Allocation was concealed from the study statistician. 306 individuals were included (age 20-65, diabetes type 2 diagnosed within the past 6 years, BMI 27-45 kg/m2, no insulin, HbA1c under 108 mmol/mol). The intervention group had all antidiabetic and antihypertensive drugs whitdrawn, total diet replacement (825-853 kcal/day formula diet for 3-5 months), stepped food reintroduction (2-8 weeks), and structured support for long-term weight loss maintenance.
At 12 months, diabetes remission was achieved in 68 (46%) participants in the intervention group and 6 (4%) participants in the control group (odds ratio 19.7, 95% CI 7.8 to 49.8; p<0.0001) and weight loss of 15 kg or more was achieved in 36 (24%) and none respectively (p<0.0001). Mean bodyweight fell by 10.0 kg (SD 8.0) in the intervention group and 1.0 kg (3.7) in the control group (adjusted difference -8.8 kg, 95% CI -10.3 to -7.3; p<0.0001). Quality of life (EuroQol 5 Dimensions visual analogue scale) improved by 7.2 points (SD 21.3) in the intervention group, and decreased by 2.9 points (15.5) in the control group (adjusted difference 6.4 points, 95% CI 2.5 to 10.3; p=0.0012).
A 2-year analysis 3 assessed the durability of the intervention of above mentioned study. At 24 months, 17 (11%) intervention participants and 3 (2%) control participants had weight loss of at least 15 kg (adjusted odds ratio [aOR] 7.49, 95% CI 2.05 to 27.32; p=0.0023) and 53 (36%) intervention participants and 5 (3%) control participants had remission of diabetes (aOR 25.82, 8.25 to 80.84; p<0.0001).
A 5-year follow-up of the above mentioned trial (DiRECT) 5 included all intervention participants (101/149, 68%) who were after 2 years still in the trial. They received low-intensity support for a further 3 years (extension group). In the non-extension group (n=54) the intervention was withdrawn. At 5 years, extension participants (n=85) lost an average of 6.1 kg, with 13% in remission. Compared with the non-extension group, extension group had more visits with HbA1c <48 mmol/mol (<6.5%; 36% vs 17%, p=0.0004), without glucose-lowering medication (62% vs 30%, p<0.0001), and in remission (34% vs 12%, p<0.0001). Original control participants (n=149) had mean weight loss 4.6 kg, and 5% were in remission. Compared with control participants, original intervention participants had more visits with weight more than 5% below baseline (61% vs 29%, p<0.0001), HbA1c below 48 mmol/mol (29% vs 15%, p=0.0002), without antidiabetic medication (51% vs 16%, p<0.0001), and in remission (27% vs 4%, p<0.0001). Of those in remission at year 2, 26% remained in remission at 5 years. Serious adverse events in the original intervention group were under half those in the control group (4.8 vs.10.2 per 100 patient-years).
A DiRECT-Aus 6 included 155 participants in Australian primary care setting. At 12 months, T2D remission was achieved in 86 (56%) participants, with a mean adjusted weight loss of 8.1% (95% CI 7.2 to 9.1).
Another open-label, cluster-randomised trial 4 included 158 participants. The intensive lifestyle intervention comprised a total diet replacement phase with low-energy diet meal replacement formula followed by gradual food reintroduction combined with physical activity support, and a weight-loss maintenance phase, involving structured lifestyle support. Control group received usual diabetes care. At 12 months, the mean bodyweight in the intervention group reduced by 11.98 kg (95% CI 9.72 to 14.23) compared with 3.98 kg (2.78 to 5.18) in the control group (adjusted mean difference -6.08 kg [95% CI -8.37 to -3.79]. In the intervention group, 21% of participants achieved more than 15% weight loss compared with 1% of participants in the control group (p<0.0001). Diabetes remission occurred in 61% of participants in the intervention group compared with 12% of those in the control group (odds ratio 12.03, 95% CI 5.17 to 28.03).
A nonrandomized, prospective, controlled study 7 analyzing the effects of bariatric surgery on the prevention of T2D included 1658 patients who underwent bariatric surgery (banding, vertical banded gastroplasty, or gastric bypass) and 1771 obese matched controls. During the 15 years follow-up period, T2D developed in 392 participants in the control group and in 110 in the bariatric-surgery group, corresponding to incidence rates of 28.4 cases per 1000 person-years and 6.8 cases per 1000 person-years, respectively (adjusted hazard ratio with bariatric surgery, 0.17; 95% CI 0.13 to 0.21; P<0.001). The postoperative mortality was 0.2%, and 2.8% required reoperation within 90 days owing to complications.
Date of latest search: 2024-12-05
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