Antidepressant Drug Use in Patients With T2D Lacks Research

researchers published the study covered in this summary on as a preprint that has not yet been reviewed.

Key Takeaways

  • The authors of this systematic review attempted to assess and synthesize the long-term outcomes from observational studies of people with type 2 diabetes and comorbid depression who received treatment with prescribed antidepressants.

  • No studies were identified that matched the investigators’ prespecified inclusion criteria. The main reasons for exclusion were failure to meet the authors’ inclusion criteria for antidepressant treatment; unspecified case definitions for depression, type 2 diabetes, or both; short or unspecified duration of antidepressant treatment; and overly brief follow-up to assess outcomes.

Why This Matters

  • An estimated one quarter of people with type 2 diabetes have comorbid depression, and evidence shows an increased prevalence of depression in people with type 2 diabetes compared to those without. Depression is associated with poor glycemic control, development of diabetes-related complications, and decreased adherence to diabetes treatments. Successful treatment of depression in people with type 2 diabetes can potentially enhance both the physical and mental health of these patients.

  • Despite the potentially high number of people with type 2 diabetes and comorbid depression treated with antidepressants, the long-term impact of the treatment in this patient group is unknown.

  • The authors say this is the first systematic review that focuses on observational studies of the long-term outcomes of antidepressant treatment prescribed for the recommended minimum duration of at least 6 months in individuals with type 2 diabetes and comorbid depression. Previous reviews focused on results from randomized controlled trials, and the maximum follow-up of these trials was no more than 6 months.

Study Design

  • The investigators registered the design of their systematic review of observational studies prospectively on the PROSPERO website, run by the National Institute for Health and Care Research.

  • The prespecified inclusion criteria encompassed observational studies of adults with both diagnosed depression and type 2 diabetes established with a record of a clinical diagnosis or patient self-report. In addition, patients had to have received antidepressant treatment for at least 6 months, and overall follow-up had to be for a minimum of 12 months. The researchers searched a variety of medical literature databases for relevant studies published through May 2021.

Key Results

  • The researchers screened 14,389 unique abstracts, a process that identified 63 full texts that qualified for a detailed review of their eligibility by the prespecified standards. No study that met all the inclusion criteria was identified during this process.

  • Shortcomings that led to exclusion of studies from the analysis (many studies had more than one excluding feature) included 49 did not meet the prespecified inclusion criteria for antidepressant use; 36 used an insufficient case definition for type 2 diabetes; 29 used an insufficient case definition for depression; 25 had insufficient follow-up; 14 had an incorrect study design; five did not use measurable outcomes; and three did not use a suitable comparator group.

  • The most common reason for exclusion, for 49 reports, was failure to meet the inclusion criteria for antidepressant treatment. This included 15 studies that didn’t identify a group of participants who were all known to have received antidepressant prescriptions through self-report, prescription records, or a clinician’s report. An additional 34 studies didn’t specify the duration of antidepressant treatment or didn’t meet the inclusion criteria of a minimum 6 months of treatment.


  • The authors note that they applied strict inclusion and exclusion criteria for identifying patients with depression and type 2 diabetes, and that they also required a 6-month minimum duration of antidepressant treatment and follow-up. They said they applied these criteria to identify high quality and robust studies. They also rationalized the 6-month minimum follow-up criterion as reflecting treatment guidelines for use of antidepressant medications and to better represent long-term responses to treatment rather than initial responses.


  • The study received no commercial funding.

  • Most of the authors had no commercial disclosures. One author, Ian CK Wong, reported being a board member for Jacobsen Medical and has received research grants from Amgen, Bayer, Bristol Myers Squibb, GlaxoSmithKline, Janssen, Medice, Novartis, and Pfizer.

This is a summary of a preprint research study, “A Systematic Review of Long-term Antidepressant Outcomes in Comorbid Depression and Type 2 Diabetes,” written by authors primarily based at University College London, UK, on ​​medRxiv provided to you by Medscape. This study has not yet been reviewed. The full text of the study can be found on


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