Hypoglycaemia in People With Type 2 Diabetes in Primary Care

Background - previous studies have provided robust evidence on the link between intensive therapy and increased frequency of hypoglycaemia in people with type 1 diabetes. Despite type 2 diabetes comprising the majority of cases of diabetes, the overall frequency of hypoglycaemia in this group has not been as carefully documented as in type 1 diabetes, particularly in relation to the clinical use of individual therapies in primary care.

Recent prospective studies suggest that hypoglycaemia occurs more frequently than was previously thought for people with type 2 diabetes, particularly those treated with insulin and sulphonylureas. An increasingly elderly population, and earlier initiation of insulin and other newer therapies and treatment combinations, may influence the risk and severity of hypoglycaemic episodes.

The overall aim is to undertake research that provides robust data on the frequency and severity of hypoglycaemia in people with type 2 diabetes managed in primary care, and assess and explore associated risk factors.

PROSPECTIVE STUDY Aims - to prospectively evaluate the self-reported frequency and severity of hypoglycaemia in people with type 2 diabetes managed in primary care (stratified by participant treatment regime); to investigate the associated clinical and demographic predictors of hypoglycaemia.

Methods - we will undertake a prospective, observational cohort study. Firstly, general practices will be approached to participate in the study, with an aim of recruiting around 20 practices throughout the UK. All recruited sites will receive relevant study training for the purposes of recruiting participants and collecting/recording research data. Participating general practices will then identify potentially eligible individuals on their practice register; individuals will be invited via a study invitation pack sent in the post or given in person when they attend the practice. Individuals expressing an interest will be invited to attend an appointment at their general practice where informed consent will be obtained and baseline data collected (demographic, bio-medical and self-completion questionnaires). Participants will be provided with relevant study materials (glucose monitoring diaries, hypoglycaemia recording forms, and a blood glucose meter and strips) and asked to measure their blood glucose and record any episodes of hypoglycaemia, over a period of 12-months. Repeat biomedical and self-completion questionnaire data will be collected at 12-months follow-up.

The overall sample size for the prospective study is 422, based on recruiting a quota of participants on the following treatment regimens: 1) metformin only (n=62); 2) sulphonylurea based (n=140); 3) insulin based (n=140); and 4) incretin based (Dipeptidyl peptidase-4 (DPP4) or Glucagon-like peptide-1 (GLP-1)), (n=80). Practices will be asked to continue recruitment until targets are met for each of the treatment groups.

CROSS SECTIONAL STUDY Aim - to provide data on the prevalence of hypoglycaemia in people with type 2 diabetes who are managed in primary care and explore associated risk factors.

Methods - approach for participation will be made when potential volunteers attend for a planned appointment for diabetes care (e.g. diabetes annual review, diabetic retinopathy screening), through poster advertisement at the site. Their healthcare professional will also explain that there is a researcher at the clinic who is recruiting individuals with type 2 diabetes to take part in a research study. The researcher will then approach potential volunteers to provide a brief verbal explanation of the study, followed by a written participant information sheet for them to read. Subsequently, for individuals who volunteer to participate, they will be asked to sign a consent form and then given a questionnaire to self-complete (at their appointment or take home and post back to the research team). In addition, a researcher will obtain biomedical data from participants' medical records; no data will be collected until at least 48 hours has passed from the time informed consent was obtained, to allow time for participants who may change their mind about taking part.

The anticipated recruitment target for the cross-sectional study is to recruit up to 2000 participants.

PROSPECTIVE STUDY

Inclusion criteria

• Confirmed diagnosis of type 2 diabetes mellitus
• Diagnosis at least 6 months prior to recruitment
• Registered at participating general practice
• Aged ≥ 18 years old
• On one of the following treatment regimens:

• metformin only
• sulphonylurea based (not on insulin or incretin-based therapy)
• insulin based (not on sulphonylurea, GLP-1 or DPP-4)
• incretin or incretin based therapy, DPP-4 or GLP-1 (not on sulphonylureas or insulin)
• HbA1c <9.0% at last reading Willingness to self-report episodes of hypoglycaemia and undertake home blood glucose self-monitoring for 12-months

Exclusion criteria

• Participant managed exclusively in secondary care
• Severe diabetic complications e.g. corrected visual acuity less than 6/12 in both eyes, major limb amputation or severe peripheral sensory neuropathy
• History of seizures unrelated to hypoglycaemia
• Severe systemic disease unrelated to diabetes
• Pregnancy
• Any reason why the participant may not be able to understand instructions or be unable or unwilling to co-operate with the study staff e.g. mental incapacity, language barriers

CROSS-SECTIONAL STUDY

Inclusion criteria

• Confirmed diagnosis of type 2 diabetes mellitus
• Diagnosis at least 6 months prior to recruitment
• Registered at a general practice within Leicestershire, Rutland or Northamptonshire
• Treatment for type 2 diabetes includes oral hypoglycaemic drugs and/ or insulin

Exclusion criteria

• Any reason why the participant may not be able to understand instructions or be unable or unwilling to co-operate with the study staff e.g. mental incapacity, language barriers
• Aged ≥ 18 years old