Cardiovascular diseases, overweight, type 2 diabetes and chronic kidney disease increase the risk of cardiovascular events.

Glucagon-like peptide-1 analogues are recommended by the European Society of Cardiology and the American College of Cardiology to lower the risk of death and progression of cardiovascular disease in patients with cardiovascular disease and type 2 diabetes. Semaglutide, tirzepatide and liraglutide are approved by the US Food and Drug Administration and the European Medicines Agency for the treatment of type 2 diabetes mellitus and overweight. CagriSema is currently not approved, but several phase III trials are ongoing.

No previous systematic review has investigated the effects of semaglutide, tirzepatide, CagriSema and liraglutide, which may not be disease-specific, on hard binary outcomes for all trial populations at increased risk of cardiovascular events.

We will conduct a systematic review and search major medical databases (Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, Latin American and Caribbean Health Sciences Literature, Science Citation Index Expanded, Conference Proceedings Citation Index—Science) and clinical trial registries from their inception and onwards to identify relevant randomised trials. We expect to perform the literature search in December 2025. Two review authors will independently extract data and assess the risk of bias. We will include randomised trials assessing the effects of semaglutide, tirzepatide, CagriSema and/or liraglutide in participants with an increased risk of cardiovascular events. The primary outcome will be all-cause mortality. Secondary outcomes will be myocardial infarction, stroke and all-cause hospitalisation. Data will be synthesised by aggregate data meta-analyses, Trial Sequential Analyses and network meta-analysis, risk of bias will be assessed with Cochrane Risk of Bias tool V. 2, and the certainty of the evidence will be assessed by Grading of Recommendations, Assessment, Development and Evaluations and the Confidence in Network Meta-Analysis approach.

This protocol does not present any results. Findings of this systematic review will be published in international peer-reviewed scientific journals.

CRD42024623312.

Parkinson’s disease is a neurological disease with a rising incidence and prevalence. Patients with Parkinson’s disease may receive antipsychotics, for example, due to Parkinson’s disease psychosis. Parkinson’s disease psychosis is characterised by visual hallucinations and other psychotic symptoms. To date, no systematic review has evaluated the effects of antipsychotics in patients with Parkinson’s disease. Therefore, this review aims to assess the beneficial and harmful effects of antipsychotics for Parkinson’s disease.

This is a protocol for a systematic review. A search specialist will perform a search in major medical databases (eg, MEDLINE (Medical Literature Analysis and Retrieval System Online), EMBASE (Excerpta Medica database), CENTRAL (Cochrane Central Register of Controlled Trials)) and clinical trial registries. Published and unpublished randomised clinical trials comparing antipsychotics to any control (placebo, standard care or other antipsychotics) in patients with Parkinson’s disease will be included. Two review authors will independently extract data and conduct risk of bias assessments with the Cochrane Risk of Bias tool—V.2. Primary outcomes will be all-cause mortality, serious adverse events and significant falls. Secondary outcomes will be hospitalisations, non-serious adverse events, Unified Parkinson’s Disease Rating Scale total score and psychotic symptoms using any valid symptom scale. Data will be synthesised by aggregate meta-analysis, trial sequential analysis and network meta-analysis. Several subgroup analyses are planned. An eight-step procedure will be used to assess if the thresholds for clinical significance are crossed, and the certainty of the evidence will be assessed by GRADE (Grading of Recommendations Assessment, Development and Evaluations) and CiNeMA (Confidence in Network Meta-Analysis) approach.

This protocol does not include results, and ethics approval is not required for the project. The findings from the systematic review will be published in international peer-reviewed scientific journals.

PROSPERO ID: CRD42025633985. Available from https://www.crd.york.ac.uk/PROSPERO/view/CRD42025633985.