Exogenous insulin use and hypertension in adult patients with type 2 diabetes mellitus.

BACKGROUND: Endogenous hyperinsulinemia, along with insulin resistance, is associated with hypertension. This study investigated the link between exogenous insulin use and hypertension in patients with type 2 diabetes mellitus.
METHODS: Using national health insurance records in Taiwan, data from 87,850 adult patients with type 2 diabetes mellitus were collected cross-sectionally with retrospective recall for onset of events. Data were analyzed to evaluate the strength of association, consistency, dose-response relationship, and temporality between exogenous insulin use and hypertension.
RESULTS: There were 5927 insulin users, who were characterized by being 1 year older in age, female preponderance, longer duration of diabetes, slightly lower body mass index, and less smoking but higher prevalence of hypertension with higher blood pressure. After adjustment for age, sex, body mass index, duration of diabetes, smoking, and parental hypertension, the odds ratios (95% confidence interval [CI]) for hypertension for patients using insulin for less than 5 years, 5 to 9 years, and 10 years or more were 1.14 (95% CI, 1.06-1.23), 1.35 (95% CI, 1.18-1.54), and 1.46 (95% CI, 1.24-1.74), respectively, compared with nonusers. In insulin users who did not have hypertension at the start of insulin use, the respective odds ratios for those using insulin for 5 to 9 years and 10 years or more were 1.5 (95% CI, 1.25-1.80) and 2.15 (95% CI, 1.72-2.70), respectively, compared with those using insulin for less than 5 years.
CONCLUSIONS: In patients with type 2 diabetes mellitus, insulin users are at higher risk for development of hypertension. These observational data suggest the need for further study of the relationship between exogenous insulin use and hypertension.