Background. The treatment goals in type 1 diabetes are near-normal blood glucose values and glycated haemoglobin (HbA1c) < 7% (< 53 mmol/mol). This can be achieved with intensive insulin therapy (multiple daily injections or pump therapy) and frequent self-monitoring of blood glucose (SMBG). Only few studies have addressed directly, in a randomised setting, the association between frequency of SMBG and glycaemic control.
Aim. The aim of the current study was to demonstrate that SMBG at least 4 times daily results in a significant decrease in HbA1c without an increased risk of major or nocturnal hypoglycaemia.
Methods. This was a 25-week randomised study consucted in two specialised centres in Estonia. After the 5-week screening phase, 20 adult subjects with type 1 diabetes receiving multiple injections with insulin glargine 1–2 times daily and a short-acting analogue (lispro, aspart, or glulisine) 3 times daily were randomised into 2 groups: the first group (n = 12) were given glycometer test strips free of charge and they committed to perform SMBG at least 4 times daily; the control group (n = 8) continued to perform SMBG according to their previous habits, using test strips reimbursed by the Estonian Health Insurance Fund (600 per year, average 1.6 per day). In addition, the control group was asked to perform the 5-point blood glucose profi le once weekly. After the randomisation all subjects were scheduled for 6 visits (including 2 phone call visits). The HbA1c was measured 8 weeks and 20 weeks after the randomisation. Diff erences in the decrease of HbA1c were compared using the Mann-Whitney U-test.
Results. In the intensive SMBG group, the mean HbA1c was 9.04% (95% CI = 8.71–9.37%) at randomisation, and it dropped to 8.08% (95% CI = 7.69–8.48%) by the end of the study. In the control group, the mean HbA1c was 8.54% (95% CI = 8.22–8.86%) and 8.74% (95% CI = 8.36–9.11%) at randomisation and at the end of the study, respectively. This translated to a mean decrease of 0.96% in HbA1c (95% CI = -1.19 – -0.73%) in the intervention group, while in the control group, HbA1c increased by 0.2% (95% CI = -0.05–0.45%) (p < 0.001). None of the study subjects had major hypoglycaemia episodes. Four subjects in the intensive SMBG group, and 6 subjects in the control group experienced nocturnal hypoglycaemia; the total event rate was 19 and 13 in the intensive SMBG group and in the control group, respectively.
Conclusions. Intensive SMBG significantly improves glycaemic control in patients with type 1 diabetes without an increased risk of major or nocturnal hypoglycaemia. However, in inadequately compensated patients, HbA1c < 7% (< 53 mmol/mol) remains a challenge despite intensive insulin treatment and frequent SMBG.