Use ABPM to Assess Diabetes Cardiovascular Risk

Patients with type 2 diabetes mellitus (DM) should be monitored with ambulatory blood pressure monitoring (ABPM) if they are at high risk for cardiovascular complications, according to the results of a new study.

“ABPM provides more valuable information regarding cardiovascular risk stratification than office blood pressures and should be performed, if possible, in every high-risk type 2 diabetic patient,” states lead author Gil Salles, MD, of the University Hospital Clementino Fraga Filho in Rio de Janeiro, Brazil.

The prognostic importance of tight clinic blood pressure control is controversial among patients with DM. Dr Salles and colleagues set out to investigate the prognostic impact of clinic and ambulatory blood pressures for cardiovascular morbidity and mortality in type 2 DM.

The prospective Rio de Janeiro Type 2 Diabetes Cohort Study monitored 565 patients at high risk for cardiovascular disease for a median of 5¾ years. The patients were assessed using both ambulatory blood pressure monitoring (ABPM) and conventional digital blood pressure monitoring. Patient follow-up was conducted at least 3 or 4 times a year, with clinic blood pressure assessed at least 4 times and ABPM at least twice overall. Blood pressure readings were linked to a composite end point of fatal and nonfatal cardiovascular events and all-cause mortality. Multivariable analyses assessed associations between each blood pressure component and the composite end point.

A total of 88 (15.6%) patients experienced a cardiovascular event, including 38 who died of cardiovascular-related causes. There were 70 deaths (12.4%) resulting from any cause.

After adjustments for cardiovascular risk factors, clinic systolic blood pressure and diastolic blood pressures were predictive of the composite end point but not of all-cause mortality. However, all ambulatory blood pressure components were predictors of both end points, the authors note.

ABPM predicted cardiovascular risk at lower blood pressure levels (120/75 mm Hg or higher) than clinic-derived measurements (140/90 mm Hg or higher) over a 24-hour period, signaling an increased cardiovascular risk. What’s more, additional ABPM readings improved cardiovascular risk stratification over the course of follow-up, but further clinic blood pressure monitoring did not improve the risk prediction.

“Achieved 24-hour ambulatory blood pressures lower than 120/75 mm Hg are associated with significant cardiovascular protection and, if confirmed by other studies, may be considered as blood pressure treatment targets,” the authors state.

The authors note that the vast majority (86.3%) of recruited patients had arterial hypertension at baseline and most were already taking antihypertensive medication when they entered the study. Antihypertensive treatment also may have attenuated the results and made the relative risk estimate more conservative, they suggest.

Dr Salles and colleagues conclude that “the Rio de Janeiro Type 2 Diabetes Cohort Study supports the use of ABPM in every high-risk type 2 diabetic individual to improve cardiovascular risk stratification and to target blood pressure goals during antihypertensive treatment, over and beyond clinic blood pressures.”

The authors presented theirresults in the November 5, 2013, issue of the Journal of Hypertension.