In patients with type 2 diabetes, long-term systolic blood pressure (BP) variability is associated with an increased risk of death and cardiovascular events, independently of mean BP values, a meta-analysis found.
The included studies prospectively or retrospectively assessed the association of BP variability and the incidence of at least one of the following outcomes in patients with type 2 diabetes: all-cause mortality, major adverse cardiovascular events (MACEs), extended MACEs, microvascular complications, and/or hypertension-mediated organ damage. Studies were excluded if they had less than two years of follow-up or were conducted in pediatric patients, pregnant women, patients with type 1 diabetes, patients on hemodialysis, those with end-stage renal disease, or those with solid or hematological malignancies.
The meta-analysis included 26 papers with a total of 377,305 patients. Eighteen papers reported data on long-term (visit-to-visit) BP variability, and eight reported data on short-term (ambulatory and/or home BP monitoring) variability. Five studies had information on all-cause mortality, seven analyzed MACEs (cardiovascular death, nonfatal myocardial infarction, and nonfatal stroke), 14 analyzed extended MACEs (cardiovascular death, nonfatal myocardial infarction, fatal and nonfatal stroke, and peripheral arterial disease), and nine assessed microvascular complications (neuropathy, nephropathy/development of microalbuminuria, and retinopathy). Four reporting on hypertension-mediated organ damage were qualitatively analyzed and reported separately. Results were published online on July 7 by Diabetes, Obesity and Metabolism.
Systolic BP variability was associated with a significantly increased risk of all-cause mortality (hazard ratio [HR], 1.12; 95% CI, 1.04 to 1.21), MACEs (HR, 1.10; 95% CI, 1.04 to 1.17), extended MACEs (HR, 1.08; 95% CI, 1.02 to 1.17), and microvascular complications (HR, 1.12; 95% CI, 1.01 to 1.24). Associations were mainly driven from studies on long-term systolic BP variability. Qualitative analysis showed that BP variability was associated with the presence of hypertension-mediated organ damage, expressed as carotid intima-media thickness, pulse wave velocity, and left ventricular hypertrophy. Results were independent of mean BP, glycemic control, and serum creatinine levels.
Diastolic BP variability (short- and long-term) did not show the same predictive role for the outcomes studied, although only a limited number of studies explored this association. Other limitations of the meta-analysis were its relatively low number of studies, as well as substantial heterogeneity across studies for most outcomes, the authors noted.
“Current guidelines consider only the absolute value of blood pressure as a tool to stratify the patient's cardiovascular risk. … Our results suggest that BP variability could provide a substantial contribution to the correct stratification of [cardiovascular disease] risk in patients with type 2 diabetes,” they concluded.