Anti-depressant and anti-psychotic drug use in people with diabetes

Additional Supervisor: Prof Daniel J Smith (University of Glasgow)

Background

There is thought to be a bi-directional association between diabetes and depression. About 20-30% of patients with diabetes have a co-morbid depressive disorder, with this comorbidity associated with poorer glycaemic control and adverse health outcomes such as vascular disease.1 Similarly, schizophrenia is thought to be associated with a two- to three-fold increased risk of diabetes.2 However, the impact of co-morbid schizophrenia on diabetes outcomes remains unclear.

The independent role of anti-depressant medication (which may also be used to treat other conditions including diabetic neuropathy) and anti-psychotic drugs on risk of adverse outcomes in people with diabetes is unclear.1,3 Furthermore, the effects of many newer antidepressant medications and combination therapy (i.e. antidepressant polypharmacy) remain under-investigated. Off-label prescribing of anti-psychotic drugs is increasing, with some being prescribed for treatment of dementia, post-traumatic stress, anxiety and insomnia.

Identification of particular drugs or drug combinations which might place individuals at greater risk of undesirable health outcomes would inform more appropriate and less risky treatment options. It would also inform subsequent projects aimed at identifying patients who might be at greatest risk of particular side-effects from certain drugs, thus informing more tailored drug prescription practices and ultimately providing more personalised effective patient treatment.

Scotland is in a leading position to exploit health data and is uniquely placed in having high-quality linkable datasets optimised for research purposes. These datasets include the Scottish Care Information-Diabetes (SCI-Diabetes) dataset, which holds clinical care and prescription data on around 400,000 people with diabetes in Scotland and is linked to other routinely collected datasets, facilitating the study of short- and long-term health outcomes.4 The supervisors of this PhD project are currently leading a major new national data linkage study focused on the effect of co-morbid major mental disorder on outcomes and complications of diabetes, stroke and heart attack. The proposed PhD project will add a further layer of investigation to the work on diabetes, specifically drilling deeper into the effects of anti-depressant and anti-psychotic drug use on a range of outcomes.

Aims

To investigate patterns of antidepressant and antipsychotic drug use among patients with diabetes and determine their associations with diabetic complications and outcomes

The specific objectives are:

1. Describe the frequency of anti-depressant and anti-psychotic drug use among people with diabetes
2. Investigate whether anti-depressant/anti-psychotic drug use in patients with diabetes is associated with glycaemic control, blood pressure, and body mass index
3. Investigate whether anti-depressant/anti-psychotic drug use in patients with diabetes is associated with risk of vascular disease and diabetic complications (e.g. retinopathy) before and after considering the role of known risk factors
4. Within objectives 2 and 3, examine whether associations differ by drug class or drug combination

Training Outcomes

Completion of this PhD will provide the student with a unique skill-set encompassing epidemiology, pharmaco-epidemiology, statistics, psychiatry and the use of large, linked routine datasets. This cross-disciplinary expertise will place them in a prime position to make a valuable contribution to the field of mental health-physical disease research, and in particular to the rapidly advancing field of data science. They will also be equipped with sought-after transferrable skills, which can be applied to other disciplines and sectors. The student will benefit from internal training courses on generic research skills, statistical analyses and epidemiology. They will have the opportunity to attend training in pharmaco-epidemiology at the London School of Hygiene and Tropical Medicine and in the theory and practice of large datasets of linked health data, offered by the University of Western Australia, via Swansea University. The student will be encouraged to present their work to lay and professional audiences and submit journal articles to international peer-reviewed journals.

This MRC programme is joint between the Universities of Edinburgh and Glasgow. You will be registered at the host institution of the primary supervisor detailed in your project selection.

All applications should be made via the University of Edinburgh, irrespective of project location:

http://www.ed.ac.uk/studying/postgraduate/degrees/index.php?r=site/view&id=919

Please note, you must apply to one of the projects and you are encouraged to contact the primary supervisor prior to making your application. Additional information on the application process if available from the link above.

For more information about Precision Medicine visit:

http://www.ed.ac.uk/usher/precision-medicine