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

Background Severe hypoglycaemic episodes are an important source of morbidi ty in people with Type 1 diabetes. The occurrence of severe hypoglycaemia i s 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 I diabetes treated wi th multiple insulin injection therapy. Methods We studied 31 patients with Type 1 diabetes in reasonable glycaemic control (HbA(1c)less than or equal to 8.3%) during multiple injection ther apy. The study had a prospective, observational design. We used standardise d home blood glucose monitoring (HBGM) diaries to assess the frequency of h ypoglycaemia (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 fact ors [average and standard deviation (SD) of the HBGM readings and self-repo rted hypoglycaemia awareness]. Results Determinants of mild hypoglycaemia frequency identified in univaria te regression analyses were: SD and mean of HBGM (beta 0.6, p = 0.001 and b eta -0.6, p = 0.001), diabetes duration (beta 0.5, p = 0.008) and self-repo rted 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 e xternal eating behaviour (beta -0.3, p = 0.1). These relations were confirm ed in multivariate analyses. Conclusions Patients with Type I diabetes who have a high blood glucose var iability and low average blood glucose concentration, diabetes of long dura tion, low body mass index, self-reported impaired awareness of hypoglycaemi a and those participating in vigorous physical activities, specifically req uire interventions aimed at preventing hypoglycaemia. Copyright (C) 2000 Jo hn Wiley & Sons, Ltd.