Proportion of daily capillary blood glucose readings required in the target range for target glycaemic control: shift of focus from target range to proportion in range

Aim Most guidelines provide people with Type 1 diabetes with pre‐ and post‐meal capillary blood glucose ( CBG ) targets to achieve optimal glycaemic control. We evaluated the proportion of daily CBG readings between 4 and 10 mmol/l in people achieving different HbA 1c levels. Method We analysed CBG data from routine pump/meter downloads from 201 adults treated with continuous subcutaneous insulin infusion ( CSII ) at a single hospital clinic. Exclusion criteria were CSII < 6 months, < 3 CBG /day, pregnancy, haemoglobinopathy and continuous sensor use. People were categorized into three groups based on HbA 1c : < 58 mmol/mol, < 7.5% ( n = 58); 58–74 mmol/mol, 7.5–8.9% ( n = 107); and ≥ 75 mmol/mol, ≥ 9.0% ( n = 36). Results Participants had a mean age of 43 ± 13 years and mean HBA 1c of 64 mmol/mol (8.0 ± 1.1%). 47% of people started CSII for raised HbA 1c , 25% due to hypoglycaemia and the rest during pregnancy. Downloads contained a mean of 22 ± 6.8 days of data per participant. CBG frequency was similar between the three groups (5.6 ± 2.0, 5.6 ± 1.9 and 5.4 ± 1.2 CBG /day; P = 0.468). The proportion of CBG readings between 4 and 10 mmol/l (72–180 mg/dl) was 57.3 ± 25.4%, 50.6 ± 11.1% and 39.9 ± 16.5% ( P < 0.0001); < 4 mmol was 13.8%, 8.8% and 4.4% ( P < 0.0001) and > 10 mmol/l was 28.9 ± 16.5%, 40.6 ± 12.1% and 55.6 ± 17.9% ( P < 0.0001) in the three groups respectively. Conclusions Participants achieving HBA 1c < 58 mmol/mol (< 7.5%) had ~ 60% of CBG readings in range (4–10 mmol/l), with up to 30% of readings > 10 mmol/l. This target of achieving 60% or more readings within target, and being permissive with up to 30% readings > 10 mmol/l may be a novel target for people with diabetes, and may reduce anxiety associated with readings out of range.