Lower blood pressure associated with higher mortality in elderly diabetic patients (ZODIAC-12)

OBJECTIVE: to investigate the relationship between blood pressure over time and mortality in elderly patients with type 2 diabetes mellitus (T2DM). DESIGN: prospective observational cohort study. SETTING: primary care, Zwolle, The Netherlands. SUBJECTS: patients with T2DM aged 60 years and older (n = 881). The cohort was divided into two age categories: 60-75 years and older than 75 years. METHODS: updated means for systolic, diastolic and pulse pressures were calculated after a median follow-up time of 9.8 years. These values were used as time-dependent covariates in a Cox proportional hazard model. Main outcome measures were all-cause and cardiovascular mortality. RESULTS: all of the blood pressure measures were inversely related to all-cause mortality in elderly diabetic patients (>75 years). Furthermore, these relationships were specifically found in elderly patients treated with antihypertensive medication at baseline. A decrease of 10 mm Hg in systolic blood pressure, diastolic blood pressure and pulse pressure led to a mortality increase of 22% [95% confidence interval (95% CI): 13-31%], 30% [95% CI: 13%-46%] and 22% [95% CI: 11%-33%], respectively. In the low age group (60-75 years), no relationship was found between blood pressure and mortality. CONCLUSIONS: blood pressure is a marker for mortality in elderly T2DM patients; however, the relationship is inverse.