Biological and behavioural determinants of the frequency of mild, biochemical hypoglycaemia in patients with Type 1 diabetes on multiple insulin injection therapy

Severe hypoglycaemic episodes are an important source of morbidity in people with Type 1 diabetes. The occurrence of severe hypoglycaemia is strongly related to the frequency of low blood glucose readings. The aim of this exploratory study was to identify determinants of the frequency of mild, biochemical hypoglycaemia in patients with Type 1 diabetes treated with multiple insulin injection therapy. We studied 31 patients with Type 1 diabetes in reasonable glycaemic control (HbA(1c) </=8.3%) during multiple injection therapy. The study had a prospective, observational design. We used standardised home blood glucose monitoring (HBGM) diaries to assess the frequency of hypoglycaemia (HBGM readings <3.5 mmol/L) over a period of 6 weeks. Potential determinants studied included biological factors, self-management factors (including weekly total physical activity and vigorous physical activity), psychological factors (including psychological distress) and mediating factors [average and standard deviation (SD) of the HBGM readings and self-reported hypoglycaemia awareness]. Determinants of mild hypoglycaemia frequency identified in univariate regression analyses were: SD and mean of HBGM (beta 0.6, p=0.001 and beta -0.6, p=0.001), diabetes duration (beta 0.5, p=0. 008) and self-reported hypoglycaemia unawareness (beta -0.5, p=0. 003). A trend was observed for performance of vigorous physical activities (beta 0.3, p=0.06) and external eating behaviour (beta -0. 3, p=0.1). These relations were confirmed in multivariate analyses. Patients with Type 1 diabetes who have a high blood glucose variability and low average blood glucose concentration, diabetes of long duration, low body mass index, self-reported impaired awareness of hypoglycaemia and those participating in vigorous physical activities, specifically require interventions aimed at preventing hypoglycaemia