Risk of diabetes and dyslipidemia during clozapine and other antipsychotic drug treatment of schizophrenia in Iceland

Abstract

Background: Type 2 diabetes (T2D) and raised blood lipids are associated with the use of antipsychotics, not least clozapine.

Aims: To describe the prevalence of high blood glucose levels, T2D, and dyslipidemia, in association with the use of clozapine or other antipsychotics in patients with schizophrenia in Iceland.

Method: This study identified 188 patients treated with clozapine and 395 patients never treated with clozapine by searching the electronic health records of Landspitali, the National University Hospital. The comparison group consisted of Icelandic population controls. Data were obtained on blood glucose, HbA1c, and blood lipid levels from these health records.

Results: The prevalence of T2D was 14.3% in the clozapine group, where the mean age was 51.2 years, and 13.7% in the never-on-clozapine group, where the mean age was 58.6 years. Males on clozapine were 2.3-times more likely and females 4.4-times more likely to have developed T2D than controls from an age-adjusted Icelandic cohort, while males on other antipsychotics were 1.5-times more likely and females 2.3-times as likely to have T2D than controls. Only one case of ketoacidosis was identified. Triglyceride levels were significantly higher in both treatment groups compared to controls in the age-adjusted Icelandic cohort.

Conclusions: Clinicians must take active steps to reduce the risk of T2D and raised triglycerides in patients with schizophrenia. Antipsychotics were associated with a greater risk of T2D developing in females compared to males.

Keywords:

• Schizophrenia
• clozapine
• diabetes
• dyslipidemia
• metabolic

Acknowledgements

We thank Georg Vougiouklakis, Harpa Rúnarsdóttir, Sigurlaug J. Sigurðardóttir, Hrönn Scheving Guðmundsdóttir, and Vilborg Kristín Gísladóttir for assistance in retrieving additional patient data, þuríður þórðardóttir and Ingibjörg Richter for assistance with databases, Elín Björk Héðinsdóttir for assisting with references, Vilmundur Guðnason, Thor Aspelund, and Örn Ólafsson at the Icelandic Heart Association for access to comparison data from the Icelandic Heart Association, Ubaldo Benitez Hernandez for assistance with statistical analysis, and members of the CRESTAR consortium.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This project has received funding from the European Union’s Seventh Framework Programme (FP7) for research, technological development and demonstration under grant agreement no. 279227. Dr MacCabe receives salary support from the National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre at South London, Maudsley NHS Foundation Trust, and King’s College London. The views expressed are those of the authors and not necessarily those of the European Union, the NHS, the NIHR, or the UK Department of Health.