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Summer Evidence Updates

Bariatric Surgery

Previous RCTs have shown that bariatric surgery was more effective than medical or lifestyle intervention for remission of diabetes at 3 years. Now long-term data at 7 to 12 years is available from 4 RCTs.

What They Did

Bariatric surgeryMedical/behavioural interventionPrimary outcome
• Age 49*
• BMI 37*
• HbA1c 8.7*
• Age 51*
• BMI 36*
• HbA1c 8.2*
Change in HbA1c


  • Bariatric surgery had a greater reduction in HbA1c than medical/behavioural intervention. Mean difference was:
    • 1.4% at 7 years (P < 0.001)
    • 1.1% at 12 years (P < 0.002)
  • Other findings favouring bariatric surgery were fewer diabetes medications used and more patients with diabetes remission (NNT =  8 at both 7 and 12 years).
  • However, the proportion of patients in remission declined from 51% at 1 year to 13% at 12 years.

Bottom Line

  • This long-term data confirms the findings reported in the Bariatric Surgery module and provides long-term evidence supporting bariatric surgery.
  • The comparative effectiveness of GLP-1 agonists (e.g., semaglutide and tirzepatide) relative to bariatric surgery is unknown as these drugs were not used in the 4 RCTs.

Brief Updates

Exercise and Depression

  • A large systematic review and network meta-analysis (218 RCTs, n=14,170) confirmed that exercise, especially walking/jogging, yoga, and strength training helps reduce depression, especially when the exercise is intense.
  • The 2022 Depression module provides guidance on frequency, intensity, and duration in Info point 13.

Remote Cognitive Behavioural Therapy

  • A systematic review and meta-analysis in CMAJ (54 RCTs, n=5,463) found no difference between therapist-guided remote CBT and in-person CBT [Moderate Evidence].
  • Conditions included anxiety and related disorder (17 RCTs), depressive symptoms (14 RCTs), insomnia (7 RCTs), chronic pain or fatigue syndromes (6 RCTs), body image or eating disorders (5 RCTs), tinnitus (3 RCTs), alcohol use disorder (1 RCT), and mood and anxiety disorders (1 RCT).
  • This supports the guidance given in the 2024 Health Anxiety module.


  • The Mirena levonorgestrel-releasing intrauterine now has an extended indication for contraception for up to a maximum of 8 years for ages 18 to 65.
  • The 2023 Contraception Update module reported that this extension was likely to happen in Canada as it was the case in the US at the time of publication.

Online Modules Now Have Bookmarks

In an effort to improve digital accessibility we have added bookmarks to the screen compatible PDFs of the May modules (Infertility and Environmentally Sustainable Clinical Care). These bookmarks improve navigation when using screen readers and allow users to jump to specific sections of the module. If you have any feedback on this new initiative, please contact Jennie Thode at