Lower Blood Pressure Doesn’t Reduce Mortality in Type 2 Diabetes

Aggressive blood pressure reduction in the year after diagnosis of type 2 diabetes does not lead to a reduced risk of death, according to a study of primary care data in the British Medical Journal.

The researchers analyzed data from nearly 127,000 adult patients with type 2 diabetes newly diagnosed at U.K. general practices between 1990 and 2005. Systolic and diastolic blood pressures during the subsequent year were analyzed for association with mortality. Comparisons were made for patients with and without established cardiovascular disease—present in 9.8 percent of patients at baseline. Median follow-up was 3.5 years.

With adjustment for a wide range of baseline characteristics, “tight” control of blood pressure to less than 130/80 mm Hg was not associated with increased survival in patients with cardiovascular disease. For patients with systolic blood pressure of 110 mm Hg, the hazard ratio for death was 2.79, compared to those with “usual control”—systolic blood pressure 130 to 139 mm Hg. For diastolic blood pressure, hazard ratios for death were 1.32 at 70 to 74 mm Hg and 1.89 at less than 70 mm Hg, compared to usual control of 80 to 84 mm Hg.

Lower blood pressure targets were also associated with increased mortality among patients without cardiovascular disease. Similar patterns were found on analysis of patients receiving treatment for diagnosed hypertension.

Aggressive blood pressure reduction has been recommended for high-risk patients with diabetes, cardiovascular disease, or kidney disease. The new data suggest that lowering blood pressure to less than 130/80 mm Hg may be associated with increased, rather than decreased, all-cause mortality. The risk may be greatest at blood pressures less than 110/75 mm Hg [Vamos EP, et al: Association of systolic and diastolic blood pressure and all cause mortality in people with newly diagnosed type 2 diabetes: retrospective cohort study. BMJ 2012; 345: e5567].

January 2013 (Vol. 5, Number 1)