Abstract 4894: Risk Factors for Hypertension Incidence in Type 1 Diabetes: The Pittsburgh Epidemiology of Diabetes Complications Study
Recent analyses of the DCCT/EDIC demonstrated that hyperglycemia and intensive insulin therapy are associated with incident hypertension. We assessed this hypothesis in a population based cohort study of individuals with type 1 diabetes mellitus. Participants of the Pittsburgh Epidemiology of Diabetes Complications Study, a prospective cohort of childhood onset type 1 diabetes (at baseline, mean age was 28 years and mean diabetes duration 19 years), free of hypertension at baseline, were selected for study (n = 510). Hypertension incidence was defined as systolic blood pressure >140 mmHg, or diastolic blood pressure >90 mmHg, or use of medication for the treatment of high blood pressure in two consecutive study visits. Intensive insulin therapy (IIT) was defined as ≥3 injections (or pump) and ≥4 glucose tests daily. Predictors of hypertension incidence were examined using multivariable Cox proportional hazard models with backward elimination. During 18 years of follow-up, 200 (39.2%) incident cases of hypertension occurred. At study entry, incident cases were more likely to be older, have longer diabetes duration, higher levels of body mass index, HbA1, blood pressure, pulse, non-HDL cholesterol, albumin excretion rate and inflammatory markers and lower HDL cholesterol and were more likely to have had a diagnosis of confirmed distal symmetric polyneuropathy, microalbuminuria, and overt nephropathy compared to non-cases. Cases were also less likely to practice IIT. In multivariable models, significant independent predictors of hypertension incidence consisted of HbA1 (HR = 1.16, 95% CI = 1.05–1.30), IIT (HR = 0.46, 95% CI = 0.19 –1.13, p = 0.09), insulin dose per weight (HR = 0.56, 95% CI = 0.30 –1.04), systolic blood pressure (HR = 1.05, 95% CI = 1.03–1.06), pulse (HR = 1.02, 95% CI = 1.00 –1.03), albumin excretion rate (HR = 1.28 –1.17–1.39) and presence of proliferative retinopathy (HR = 1.48, 95% CI = 1.03–2.13) and coronary artery disease (HR = 1.83, 95% CI = 0.95–3.55). In conclusion, hyperglycemia is a risk factor for the development of hypertension among individuals with long-standing type 1 diabetes. Moreover, as reported in DCCT, IIT is inversely related with hypertension incidence.