ABPM more accurate risk predictor than office measurement
MedWire News: Ambulatory blood pressure measurement (ABPM) enables more accurate prediction of renal and cardiovascular (CV) risk than office measurement, a study reveals.
"The prediction of renal and CV risk among patients with chronic kidney disease (CKD)… was better with ABPM, in particular nighttime BP and an abnormal dipping pattern," write Roberto Minutolo (Second University of Naples, Italy) and colleagues.
"In contrast, office BP measurement was prognostically less informative."
The multicenter, prospective cohort study compared the prognostic role of daytime and nighttime systolic BP (SBP) and diastolic BP (DBP) in comparison with office measurement, in 436 consecutive CKD patients with a mean age of 65 years and a mean glomerular filtration rate of 42.9 ml/min/1.73m2.
Primary endpoints were time to renal death and time to fatal and nonfatal CV events that required hospitalization, including myocardial infarction, congestive heart failure, stroke, revascularization, peripheral vascular disease, and nontraumatic amputation.
In all, 41.7% of the patients were female, 36.5% had diabetes, and 30.5% had CV disease. Patients were divided into quintiles of BP under office, daytime, and nighttime measurement.
The findings, published in the Archives of Internal Medicine, revealed that 155 patients died from renal causes, while 103 patients had fatal or nonfatal CV events during the mean follow-up period of 4.2 years.
After adjusting for factors including age, gender, and body mass index, patients with a daytime SBP of 136-146 mmHg (second-highest quintile) and those with a daytime SBP higher than 146 mmHg (highest quintile) had an increased risk for the CV endpoint (hazard ratio [HR]=2.23 and HR=3.07) and renal death (HR=1.72 and HR=1.85), compared with patients with the reference daytime value of 126-135 mmHg (lowest quintile).
Correspondingly, patients with a nighttime SBP of 125-137 mmHg, and those with a SBP higher than 137 mmHg had an increased risk for the CV endpoint (HR=2.52 and HR=4.00) and renal death (HR=1.87 and HR=2.54) compared with patients with the reference value of 106-114 mmHg.
In contrast, office measurement of SBP and DBP did not predict CV or renal events.
After stratifying patient outcomes according to dipping status, nondippers (defined as patients with a night-to-day mean ambulatory BP ratio of 0.90 to 1.00) and reverse dippers (ratio >1.00) had a two-fold increased risk for renal death and CV events than dippers (ratio of 0.80 to <0.90).
"Interventional studies based on ABPM rather than office BP measurement are urgently required in this high-risk population," conclude the authors.
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By Piriya Mahendra