Insulin resistance and hypertension in patients with type 1 diabetes

Aim: The aims of this study were to determine the prevalence of hypertension in type 1 diabetes patients and to analyze its relationship with insulin resistance and other associated factors. Design and Methods: A cross-sectional study on 291 patients with type 1 immune-mediated diabetes managed at two outpatient endocrinology clinics was performed. All participants were Caucasian, 18 years or older with type 1 diabetes duration of more than 6 months, who had completed the study protocol. Hypertension was defined as blood pressure >= 130/80 mmHg or use of antihypertensive medication, excluding angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers when used as treatment for micro- or macroalbuminuria. Results: Hypertension was found in 87 [29.9% (95% confidence interval, or CI): 24.6%-35.2%] patients with type 1 diabetes. Hypertensive patients presented older age, male predominance, higher body mass index and overweight/obesity prevalence, and longer diabetes duration compared with normotensive patients. Insulin sensitivity quantified by estimated glucose disposal rate (eGDR) was lower in patients with hypertension compared with normotensives (5.2 +/- 1.4 vs. 9.1 +/- 1.2 mg kg(-1) min(-1), P<.001) and showed a negative correlation with systolic blood pressure level (r=-0.612, P<.01). In multivariate logistic regression analysis, eGDR, besides nephropathy, emerged significantly and independently associated with hypertension. An increment of 1 unit in insulin sensitivity assessed by eGDR was associated with a 5.7% decrease in hypertension prevalence (95% CI: 0.018-0.175) and the absence of nephropathy with an 88.2% decrease (95% CI: 0.15-0.92). Conclusions: Hypertension was present in approximately one third of patients with type 1 diabetes, especially in men, those with microangiopathy, overweight or obesity, older age and longer diabetes duration. Hypertension prevalence increased in parallel to the degree of renal impairment and was inversely related to insulin sensitivity. (C) 2011 Elsevier Inc. All rights reserved.