Decreased systolic blood pressure is associated with increased risk of all-cause mortality in patients with type 2 diabetes and renal impairment: A nationwide longitudinal observational study of 27,732 patients based on the Swedish National Diabetes Register

BACKGROUND: Previous studies have shown a U-shaped relationship between systolic blood pressure and risk of all-cause of mortality in patients with type 2 diabetes and renal impairment. AIMS: To evaluate the associations between time-updated systolic blood pressure and time-updated change in systolic blood pressure during the follow-up period and risk of all-cause mortality in patients with type 2 diabetes and renal impairment. PATIENTS AND METHODS: A total of 27,732 patients with type 2 diabetes and renal impairment in the Swedish National Diabetes Register were followed for 4.7 years. Time-dependent Cox models were used to estimate risk of all-cause mortality. Time-updated mean systolic blood pressure is the average of the baseline and the reported post-baseline systolic blood pressures. RESULTS: A time-updated systolic blood pressure < 130 mmHg was associated with a higher risk of all-cause mortality in patients both with and without a history of chronic heart failure (hazard ratio: 1.25, 95% confidence interval: 1.13-1.40 and hazard ratio: 1.26, 1.17-1.36, respectively). A time-updated decrease in systolic blood pressure > 10 mmHg between the last two observations was associated with higher risk of all-cause mortality (-10 to -25 mmHg; hazard ratio: 1.24, 95% confidence interval: 1.17-1.32). CONCLUSION: Both low systolic blood pressure and a decrease in systolic blood pressure during the follow-up are associated with a higher risk of all-cause mortality in patients with type 2 diabetes and renal impairment.