Gestational diabetes is one of the most common disorders of pregnancy. Affected women are more likely to go on to get type 2 diabetes than women who have not have gestational diabetes. UK guidelines advise women to be tested for diabetes at six to 13 weeks after a gestational diabetes pregnancy, and once a year from then on. This helps doctors to diagnose and manage diabetes early so that mothers can stay healthier. However, lots of women do not get tested, and most do not go every year. Often they do not know that the tests are recommended, and are not invited or reminded to attend.
In this study, we aim to understand patterns in diabetes screening after gestational diabetes. We will use clinical records, and we will not identify individual patients. We will describe how many women are screened, how long after pregnancy, which tests were used, and how many women are diagnosed with diabetes. We will also look at whether factors like the number of children someone has, which part of the UK they live in, and which general practice they attend affects likelihood screening.
This study will help us to understand current practices in medical care after gestational diabetes in the UK. This will help to inform changes to policy to improve treatment. We may find groups of women who do not go to screening or have a higher risk of diabetes, therefore need more support to attend testing.
Background
Gestational diabetes (GD) affects nearly a fifth of pregnancies in the UK, and puts mothers at an eight-fold higher risk of developing type 2 diabetes than women with normal glucose tolerance in pregnancy. National Institute for Health and Clinical Excellence (NICE) guidelines recommend that women are screened for diabetes at six to 13 weeks after pregnancy and then once a year thereafter to allow early diagnosis and management of incident diabetes. However, uptake is poor, particularly in the long term, and no large studies have reported screening rates after three years postpartum in the UK.
Aims
We therefore aim to describe diabetes screening practices in UK primary care in the long term after GD. We will also determine whether attendance varies by maternal and practice characteristics, which types of screening tests are used, and report diagnoses of glucose intolerance disorders.
Method
We will use the Clinical Practice Research Datalink (CPRD) Aurum dataset to discover patients with GD recorded in their medical record. CPRD Aurum contains deidentified patient data from GP practices in the UK that use the EMIS Web® software system.
Patient and practice characteristics and diabetes screening patterns will be summarised using descriptive statistics. We will describe coverage of diabetes testing by time since pregnancy according to variables including age, ethnicity, deprivation, and BMI at different time points. We will describe the types of test ordered and whether this was in line with the NICE guidelines at that time. Hazard ratios will be estimated with Cox regression models to examine the association between maternal characteristics and practice characteristics. In addition, survival analyses will be used to describe time since pregnancy to the last (most recent) test attended, and to diagnosis of diabetes or a glucose intolerance disorder.
Data will be analysed using STATA version 15.1 and R (latest release).
Primary outcome: record of diabetes screening tests (using any test).
Secondary outcomes: types of test used, factors associated with attendance, diagnoses of diabetes or glucose intolerance disorders.
Simon Griffin - Chief Investigator - University of Cambridge
Rebecca Dennison - Corresponding Applicant - University of Cambridge
Britt Kilian - Collaborator - University of Cambridge
Efthalia (Lina) Massou - Collaborator - University of Cambridge
Juliet Usher-Smith - Collaborator - University of Cambridge
Simon Griffin - Collaborator - University of Cambridge
Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation