Non-Diabetic Hyperglycaemia and Type 2 diabetes

Non-Diabetic Hyperglycaemia (NDH) is a condition in which blood sugar levels are above normal but aren’t in the diabetic range. People with NDH are at high risk of developing Type 2 diabetes mellitus (T2DM) if their condition isn’t managed properly. In addition to this risk, people with NDH are at risk of developing a range of other health problems that are more commonly known to be associated with T2DM. While the healthcare system in Northwest London has improved the way it manages NDH, there is a lack of real-world data on the development of health problems and healthcare service use in patients with NDH, as compared to patients with T2DM.

We aimed to measure the emergence of co-morbid health problems and healthcare service use in people diagnosed with NDH and T2DM. We also aimed to see if there were any differences in outcomes between the two conditions.

We extracted data from the Discover London SDE database. Discover London SDE is a de-identified database of healthcare records for 2.8 million people registered to a GP practice in Northwest London. We included anyone aged 18 years and over who received a diagnosis of NDH or T2DM between January 2015 and December 2020. The first date of diagnosis for each patient was used as a start date, after which all new diagnoses of co-morbid disorders and healthcare service use was counted. The co-morbidities we analysed were hypertension, lipid control, diabetic foot disease, diabetic eye disease, neuropathy, cardiovascular disease, diabetic kidney disease, obesity, and mental health problems. We then used statistical tests to see whether there were any differences in these outcomes between the two groups.

We identified 152,035 patients who received a diagnosis of NDH and 127,509 patients who received a diagnosis of T2DM between 2015 and 2020. Only 13% of these patients did not also develop one of the co-morbidities of interest. The three most common co-morbidities for NDH were hypertension, poor lipid control, and obesity. The three most common for T2DM were retinopathy, hypertension, and obesity. Four fifths of patients developed at least one of the following conditions: hypertension, hypercholesterolaemia, or obesity.

The most common form of contact with the healthcare system was with primary care services, with both groups having a high number of GP appointments, GP prescriptions, and onward referrals to secondary care services. The five most common onward referrals were hospital admissions, referral to community musculoskeletal service, referral to radiology services, referral to district nurse, and referral to diabetes structured education programme. Both groups also had a high number of inpatient admissions and A&E attendances, with strong evidence that these were higher for T2DM patients than for NDH patients. It is estimated that these inpatient admissions cost the healthcare service £142 million for NDH patients and £220 million for T2DM patients, with a further £45 million and £46 million spent on A&E attendances for each group, respectively.

Patients with both NDH and T2DM have a high rate of co-morbidities. In this study, both NDH and T2DM had a high burden of disease, with only 13% of individuals with either NDH or T2DM not found to be suffering from at least one of the co-morbidities of interest. Our finding that inpatient admissions and A&E attendances were higher for patients with T2DM illustrates the importance of managing NDH to prevent it developing into T2DM. This will improve outcomes for patients while providing cost savings to the healthcare service.