Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a relatively new class of medications approved for managing increased blood sugar levels and obesity. While the benefits of these drugs in treating these and related health problems have been well-established, recently some concerns have arisen regarding their potential impact on mental health. The European medicines regulatory body recently issued a statement on reviewing data on GLP-1RAs and their risk of suicidal thoughts and thoughts of self-harm. We aim to examine this safety warning by investigating the mental health safety of these medications among patients taking them for increased blood sugar levels or obesity treatment in England. Our study design will mirror the robust methodology employed in high-quality studies establishing how well GLP-1RAs work, aligning with UK guidelines for treating these conditions. Importantly, we will evaluate the risk of self-harm, suicidal thoughts, suicide, anxiety, and depression in patients both with and without a pre-existing history of mental health problems before initiating these medications. This approach will address a common limitation of clinical trials of excluding individuals with mental health concerns. However, following the medication approval, people with mental health concerns have the same chance to receive the same medication as people without mental health problems. Overall, this study will provide important findings about the safety profile of GLP-1RAs, guiding optimal use in clinical practice and enhancing our understanding of their impact on mental health.
We will utilise interlinked primary and secondary healthcare records to emulate the safety target trial, mirroring the design of pivotal GLP-1RA efficacy trials (obesity STEP 1 and type 2 diabetes SUSTAIN 2 trials), while aligning with the latest National Institute for Health and Care Excellence (NICE) guidelines for treating obesity and type 2 diabetes. Our approach involves two phases of planned work, one focusing on obesity (mono) treatment and the other on type 2 diabetes, examining the safety of GLP-1RAs within various dual and triple treatment contexts. The obesity trial encompasses four arms: no pharmacological intervention, orlistat, liraglutide, and semaglutide. For type 2 diabetes, we will emulate two five-arm trials, including dual treatment arms with metformin and sodium/glucose cotransporter-2 inhibitors (SGLT2Is); metformin and dipeptidyl peptidase-4 inhibitors (DPP-4Is) pioglitazone, or sulfonylureas; any dual combination of SGLT2Is, DPP-4Is, pioglitazone, or sulfonylureas; metformin and GLP-1RAs; and GLP-1RAs with either SGLT2Is, DPP-4Is, pioglitazone, or sulfonylureas. The triple treatment arms will involve combinations of metformin, SGLT2Is, and either DPP-4Is, pioglitazone, or sulfonylureas; any triple combination of SGLT2Is, DPP-4Is, pioglitazone, or sulfonylureas; metformin, GLP-1RAs, and either SGLT2Is, DPP-4Is, pioglitazone, or sulfonylureas; and any triple combination of GLP-1RAs with SGLT2Is, DPP-4Is, pioglitazone, or sulfonylureas; and insulin. We will report the incidence of mental health outcomes in each group and analyse safety outcomes using both intention-to-treat and per-protocol approaches. Inverse probability weighting based on propensity scores will address non-random assignment and adherence issues. Cox proportional hazard regression will assess treatment hazards, and subgroup analyses will provide outcome risks stratified by various factors. This study will generate important findings about the safety profile of GLP-1RAs, by enhancing our understanding of their effects on patients’ mental health and thereby guiding their optimal utilisation in routine clinical practice.
Primary outcome – self-harm (defined according to NICE as “an intentional act of self-poisoning or self-injury, irrespective of the motivation or apparent purpose of the act”, including suicide attempts and self-harm episodes that are evidently not suicidal).
Secondary outcomes – suicidal ideation, suicide (death), diagnoses and symptoms of anxiety and depression.
Negative control outcome – appendectomy.
Roger Webb - Chief Investigator - University of Manchester
Maja Radojcic - Corresponding Applicant - University of Manchester
Darren Ashcroft - Collaborator - University of Manchester
Faraz Mughal - Collaborator - Keele University
Martin Rutter - Collaborator - University of Manchester
Matthew Carr - Collaborator - University of Manchester
Navneet Kapur - Collaborator - University of Manchester
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;CPRD Aurum Ethnicity Record