No deleterious effects of tight blood glucose control on 24-hour ambulatory blood pressure in normoalbuminuric insulin-dependent diabetes mellitus patients

Intensive therapy aiming at near normalization of glucose levels effectivel y delays the onset and slows the progression of complications in insulin-de pendent diabetes mellitus (IDDM) and is recommended in most patients. Howev er, in a recent report, intensive insulin treatment was found to be associa ted with deleterious effects on nocturnal blood pressure (BP), the proposed mechanisms being subclinical nocturnal hypoglycemia or hyperinsulinemia. T he aim of the present study was to evaluate the association between glycemi c control, insulin dose, and 24-h ambulatory BP (AMBP) in a group of well-c haracterized IDDM patients. Twenty-four-h AMBP was measured in 123 normoalbuminuric [urinary albumin ex cretion (UAE) < 20 mu g/min] IDDM patients using an oscillometric technique (SpaceLabs 90207) with readings at 20-min intervals. UAE was measured by R IA. and expressed as geometric mean of three overnight collections made wit hin 1 week. Tobacco use and level of physical activity was assessed by ques tionnaire. HbA(1c) was determined by high-pressure liquid chromatography (n ondiabetic range, 4.4-6.4%), and patients were stratified into quartiles ac cording to HbA(1c) levels. Mean HbA(1c) values in the four groups were 7.0% (n = 31), 8.0% (n = 31), 8 .6% (n = 31), and 9.7% (n = 30). The groups were comparable regarding age, gender, diabetes duration, body mass index, UAE, smoking status, and physic al activity. AMBP levels were almost identical in the HbA(1c) quartiles wit h night values of (increasing HbA(1c) order): 110/63, 112/66, 112/66, and 1 13/65 mm Hg (P = 0.69/P = 0.32). There was no association between tight glu cose control and higher nocturnal BP or a more blunted circadian BP variati on. On the contrary, a weak positive correlation between night to day ratio s of mean arterial BP and HbA(1c) values was found (r = 0.26, P = 0.005), i .e, blunted circadian BP variation is most frequent in patients with high H bA(1c) values. Neither did we find doses of insulin to be associated with n ight BP (r = 0.04, P = 0.68). Tight blood glucose control is not associated with deleterious effects on 2 4-h AMBP in normoalbuminuric ID:DM patients. Intensive therapy can be imple mented without concerns of inducing high nocturnal BP and accelerating diab etic complications.