The optimal home blood pressure monitoring schedule based on the Didima outcome study

This study investigated the optimal schedule for home blood pressure (HBP) monitoring that has the greatest prognostic ability and provides the most reliable assessment of HBP. The Didima study assessed the value of HBP (duplicate morning and evening measurements, 3 days) in predicting cardiovascular events in the general population (662 adults, 8.2±0.2 years follow-up). Criteria for the optimal monitoring schedule were stabilization of mean HBP, its variability (standard deviation (s.d.)) and hazard ratios (HRs) of cardiovascular events per 1 mm Hg HBP increase. By averaging more readings (1–12), there was a progressive decline in average HBP and its s.d. and increase in HR, with most of these benefits achieved on the second day (8 readings) and little additional benefit obtained on the third day (12 readings). The first day gave higher and more unstable HBP values (higher s.d.) with less prognostic ability (lower HR). The first HBP readings per occasion gave higher values but with similar prognostic ability as the second readings taken 1 min later. There was little difference in average HBP between morning and evening readings with no prognostic superiority of morning readings. In conclusion, by averaging more readings the average HBP and its variability are reduced and the prognostic ability improved. Any aspect of HBP monitoring (first or second readings, morning or evening) has similar prognostic ability. The first day gives higher and unstable values with lower prognostic ability and should be better discarded. These data validate the HBP monitoring schedule proposed by the European Society of Hypertension.