Screening rates and health outcomes for women with a history of GDM in regional NSW: a study protocol

Introduction

In Australia and internationally, postpartum screening rates for women with GDM are low^1-5.   A recent review of the literature investigating the prevalence of postpartum screening in women with previous GDM found that between 18.5 and 61% of women received postpartum screening for T2D⁶.  Characteristics associated with women who are more likely to receive postpartum screening for T2D have been identified, however results are somewhat inconsistent between studies⁵.  Generally, postpartum screening is associated with older age at pregnancy, insulin use during pregnancy, GDM in a previous pregnancy, higher educational level, higher income, non-obese, and women with lower parity and anxiety levels^{6, 7}. In a recent Australian study, smoking and parity, independent of socioeconomic status, were associated with a higher likelihood of not attending postpartum screening⁸.  A fasting glucose of 5.4 mmol/L or more on pregnancy OGTT predicted both non-attendance for postpartum screening or an abnormal postpartum OGTT result⁸.

A number of barriers to postpartum screening have been identified, which relate to perceptions of both women and practitioners, and health care systems⁵.  In an Australian study women with previous GDM reported their most significant barrier was the inconvenience of having an OGTT⁹.  Reasons given for this included that the OGTT takes too long, they were too busy with the new baby, the need for babysitting to attend a long appointment, the need to breastfeed at the testing centre, lack of transport, and that it was too soon following caesarean section¹⁰.  Dislike of the OGTT (dislike of drink – which could be improved if served chilled and may be associated with nausea/vomiting, dislike of fasting for procedure, fear of needles), fear of being diagnosed with T2D, forgetting to attend screening appointment^{9, 10}, cultural background, language and communication have also been identified as potential barriers to understanding information, which subsequently influence postpartum screening rates¹¹.  Women with previous GDM have reported a lack of awareness of the need for postpartum diabetes screening, due to inadequate communication from medical providers⁹. This finding supports the views of both Australian and international researchers who report a lack of coordination between the hospital and primary care sectors for the care of women with GDM in the postpartum period^{6, 11, 12}.

The RACGP and the ADIPS both recommend that women diagnosed with GDM have a 75g 2-hour OGTT at 6 – 12 weeks postpartum and to repeat this annually if they are contemplating future pregnancies^{13, 14}.  To screen for T2D following GDM, RACGP guidelines recommend a fasting blood glucose or HbA1c every 3 years while ADIPS guidelines recommend either a fasting blood glucose 1-2 yearly if women are considered a low risk, or an annual HbA1c if considered high risk for development of T2D^{13, 14}.

Given the overwhelming evidence in support of postpartum screening for women with GDM, a number of strategies have been trialled over recent years to improve adherence to screening recommendations.  Some of the strategies that have increased postpartum screening rates include verbal and written reminders to both physician and patient, clinical protocols for postpartum testing, education programs for staff and women with prior GDM, electronic medical records to alert physicians to the need for screening and innovative postpartum care plans^{6, 15, 16}.

Recall registers have also been successful in increasing postpartum screening rates in women previously diagnosed with GDM¹⁷.  In Australia, women diagnosed with GDM are invited to register with the National Gestational Diabetes Register¹⁸.  On registration the woman receives GDM information, and following the pregnancy further education is provided with a reminder to visit a general practitioner for an OGTT.  Follow-up reminders are sent annually to each woman and her physician to have a screening test for T2D¹⁸.  Anecdotally, the National Gestational Diabetes Register postal reminder seems to have improved adherence to postpartum screening recommendations in recent years, however, extra reminders (delivered to women via short message service (SMS)) to promote attendance have not had any additional effect^{12, 19}.

Despite the national clinical recommendations and processes described above, processes for screening for T2D following GDM in pregnancy may differ across local health districts. There are  variations in the dissemination of information regarding the risks of developing T2D provided to women at or following diagnosis of GDM. Women may be provided with verbal and/or written information recommending an OGTT from the midwife or the diabetes educator before or after delivery and before discharge from hospital, while the NDSS posts information on “life after GDM” to women on the National Gestational Diabetes Register. Standardised guidelines could reduce confusion regarding the short and long term goals of the woman (from the provision of the pathology slip to long term education regarding  a healthy lifestyle)¹².

Ongoing postpartum screening and identification of strategies to improve postpartum screening after GDM for preventing progression to T2D are required^{7, 20, 21}.  In addition, there is a need to understand whether  increased screening uptake rates increase women’s use of preventive strategies, such as lifestyle modifications, to prevent the development of T2D²².

Study Aims

The aim of the study is to explore postnatal diabetes screening rates and health outcomes in women with a history of GDM in one regional NSW local health district.

Study Objectives:

1. Explore antenatal clinical factors, adherence with glucose screening and postpartum conversion rates of GDM to T2D.
2. Explore health outcomes and adherence with glucose screening and postpartum conversion rates of GDM to T2D.

Methods

A prospective observational study will be conducted by the diabetes services located in a NSW regional local health district (LHD).

Recruitment and eligibility

Women over the age of 18 years diagnosed with GDM will be invited to participate in the study. Study exclusion criteria will include women under the age of 18 years, a Type 1 or T2D  diagnosis, and those women who experienced a traumatic birth or neonatal consequences.

Measurement tools

Questionnaires designed to capture women’s OGTT screening rates and health information at 3, 18 and 36 months postpartum will be used. Health information will include a dietary and physical exercise question and the SF-36 questionnaire (a validated and reliable tool that measures overall self-rated health and eight health concepts: physical functioning, bodily pain, role limitations due to physical health problems, role limitations due to personal or emotional problems, emotional well-being, social functioning, energy/fatigue, and general health perceptions) (Ware et al., 1993). Quality of Life measures have been used extensively with women diagnosed with GDM (Gusmai et al., 2015).

Permission will be obtained from each participant to access electronic maternity records  (eMR) (Antenatal History Downtime form) to acquire health and birth details (including comorbidities, GDM medication and treatment, OGTT results, gestation at diagnosis, parity, and birth details –  date delivered, mode of delivery, baby’s weight, Apgar scores, complications, prematurity, admission to special care nursery and breastfeeding).

Study procedure

The Australian Diabetes in Pregnancy Society (ADIPS) guidelines recommend routine screening for GDM  at 26-28 weeks, and earlier if considered high risk. While there is no formal process at this LHD, generally upon diagnosis of GDM, women are referred to the Diabetes Service. At the first appointment with the Diabetes Service, the woman will be informed about the study and invited to participate. Those women indicating an interest in the study will be asked to complete a consent form providing permission for the study investigators to access their medical records (eMR) to obtain health and birth information. The woman will also be asked to indicate their expected due date and nominate their preferred method of contact to receive the study questionnaires (post-delivery). This information will be collated and stored securely on a password protected server by the Chief Investigator (CI), who will assign every participant with a unique code. The code will be applied to information collected on the eMR and questionnaires by the CI for de-identification purposes. The codes will be aligned to the corresponding questionnaires sent to the women. All questionnaires will be coded for tracking subsequent questionnaire responses and for anonymity on the database.

Questionnaires, along with a Participant Information Statement, will be sent to the woman approximately 3, 18 and 36 months after the birth of their child. A self-addressed return paid envelope will be provided to women who receive a paper version of the questionnaire. Alternatively, the women may choose to complete an electronic survey, the link to which will be provided on the Participant Information Statement. Women from non-English speaking backgrounds will be offered the support of an interpreter to assist with the completion of the questionnaire. Participants will be advised that completion of the questionnaire is not compulsory.

The Northern NSW LHD Human Research Ethics Committee has approved the study protocol – Research Protocol Number LNR217.

Statistical analysis

It is anticipated that approximately 20 women will be eligible to participate in this study each month. We propose to collect this data for the next three years, which equates to approximately 720 participants. With an average loss to follow-up of 20% at each data collection, it is anticipated that approximately 370 participants will complete the study.

Participant characteristics will be compared using one-way analysis of variance and unpaired t-test for continuous variables, and  chi-square for categorical variables. Mean changes in Quality of Life scores and between-group differences will be analysed using ANCOVA models.

Discussion

This research is an important step in the examination of postnatal diabetes screening rates and health outcomes in women with a history of GDM in regional NSW. It is anticipated that this study will provide information on the enablers and barriers to women receiving postnatal OGTT follow-up and increase our understanding of women’s use of preventive strategies, such as lifestyle modifications, to prevent the development of T2D. This information is important because women with previous GDM are seven times more likely to develop T2D than women without a history of GDM²³, and up to 65% of women with previous GDM will develop T2D within 5 – 16 years of pregnancy^{7, 24}. Furthermore, exposure to maternal diabetes in utero directly increases the long term risk of the child developing obesity, prediabetes and T2DM at some stage in their life^{25, 26}.  If not detected early, T2D can cause complications in subsequent pregnancies and multiple chronic comorbidities for both mother and child ^{25, 27}.

Early detection of impaired glucose tolerance or impaired fasting glucose provides a window of opportunity for women to make lifestyle modifications to prevent or delay the onset of T2D⁶. Lifestyle and pharmacological interventions in the early stages of the condition delay or prevent diabetes complications in those women who are diagnosed with T2D in the postpartum period⁵.  Detection of any form of glucose intolerance after pregnancy will also enable optimal management of blood glucose levels in subsequent pregnancies⁹.