There is increasing awareness of the impact of mental health conditions on physical health, and vice versa. Depression and type 2 diabetes are two of the most common mental and physical health conditions, with considerable contributions to individual and global burden of disease. Each condition is associated with increased rates and worsened outcomes in the other. There is a lack of evidence regarding medium-long term treatment outcomes, tolerability and safety, when of combining treatments for both depression and type 2 diabetes.
We will describe and evaluate patterns of antidepressant treatment in adults with depression and type 2 diabetes. We will then assess whether people who receive several other medications (polypharmacy) have different patterns of antidepressant prescribing, or subsequent differences in mental health outcomes, following antidepressant prescription. We will also assess whether antidepressant treatment influences subsequent physical health outcomes in type 2 diabetes and in diabetic complications. Finally we will assess whether particular combinations of other medications with antidepressants influence subsequent physical health outcomes.
The results will lead to a better understanding of treating depression in people who also have physical health conditions.
Depression and type 2 diabetes are two of the most common mental and physical health conditions, with considerable contributions to individual and global burden of disease. Each condition is associated with increased rates and worsened outcomes in the other. This study will investigate antidepressant, and co-prescriptions for diabetes and ‘polypharmacy’, treatment and outcomes in people with comorbid depression and type 2 diabetes.
Objectives: In adults with comorbid depression and type 2 diabetes (T2DM), to describe: 1)Trends of antidepressant prescribing, and co-prescriptions; 2) The influence of co-prescription on patterns of antidepressant prescribing and subsequent mental health outcomes; 3) The influence of antidepressant prescribing and co-prescriptions on physical outcomes and diabetic complications.
For adults with major depression we will estimate the prevalence of comorbid type 2 diabetes. Within this sub-population of adults with comorbid depression and type 2 diabetes, we will describe the trends in antidepressant prescription, and psychotropic and somatic polypharmacy from 2000 to 2018. We will describe drug treatment as incident and prevalent treatments, as well as continuous and cumulative durations of treatment. We will describe physical and mental health outcomes, all-cause and cause-specific mortality, and hospitalisations – we will calculate these as the number of new events/sum of person-time at risk.
We will describe the association between co-prescriptions and subsequent outcomes using hazard ratios calculated with Cox proportional hazards regression and odds ratios using logistic regression. We will examine the influence of antidepressant treatment and co-prescriptions on subsequent outcomes by comparing exposed vs unexposed individuals, exposed vs unexposed time periods in the same individual, and between different antidepressant agents/co-prescription regimens.
In adults with comorbid depression and type 2 diabetes, we aim to describe patterns of antidepressant prescribing (objective 1) and subsequent mental health outcomes (objective 2). We will assess whether these patterns and outcomes are influenced by the co-prescription of other agents (objective 2). Finally (objective 3), we aim to assess the association between antidepressant treatment and common co-prescriptions on diabetes complications and physical outcomes. Our outcomes for each objective are as follows:
Objective 1 (to investigate patterns of antidepressant prescribing, and co-prescriptions):
• Prevalence and incidence of antidepressant prescription
• Total counts of the number of medications concurrently prescribed
• Prevalence and incidence of individual medications prescribed simultaneously to antidepressant prescriptions
Objective 2 (to investigate influence of co-prescription on patterns of antidepressant prescribing and subsequent mental health outcomes):
• Antidepressant prescription patterns including: treatment duration, early discontinuation, switching antidepressant agents, augmenting antidepressant regimens with additional agents
• Suicide and non-fatal self-harm
• Contact with mental health specialist services
• Markers of mental health, including symptoms and diagnoses
Objective 3 (to investigate influence of antidepressant prescribing and co-prescriptions on physical outcomes and diabetic complications):
• Incidence of insulin commencement and time to insulin
• All cause and cause-specific mortality
• All cause and cause-specific hospital admissions
• Incidence of diabetic complications, including: CVD, CKD, neuropathy
• Markers of disease specific morbidity in diabetes and associated complications, including: HbA1C, systolic blood pressure, eGFR, cholesterol, triglycerides, c-reactive protein, BMI, homocysteine)
Joseph Hayes - Chief Investigator - University College London ( UCL )
Joseph Hayes - Corresponding Applicant - University College London ( UCL )
Annie Jeffery - Collaborator - University College London ( UCL )
Cini Bhanu - Collaborator - University College London ( UCL )
David Osborn - Collaborator - University College London ( UCL )
Ian Wong - Collaborator - University College London ( UCL )
Irene Petersen - Collaborator - University College London ( UCL )
Kate Walters - Collaborator - University College London ( UCL )
HES Accident and Emergency;HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation