The purpose of this study was to examine the effects of first, early morning and last measurements on daily average blood pressure during the ABPM. Previously done 525 ABPM were analyzed, retrospectively. 66.7% of these measures were in male patients. Mean age of all the patients was 43.3±16.1 years. Thirty-eight measurements per day every patient were planned. .The differences between the average of total measurements(n) and the average of n-1, n-2, n-3 which were calculated with the elimination of first, early morning and last measurements from total daily measurements were investigated. The mean of total average of all measurements (n) was 130.7±14.2/79.0±10.9 mmHg. The means of averages of first, early morning and last measurements were 140.5± 17.6/ 88.0±12.2, 134.3±18.3/ 81.9±13.4 and 135.2±19.4/ 82.9±13.5 mmHg respectively. The average of first, early morning and last measurements were statictically higher than the average of total measurements(n) realized during the day (p<0.001, for both systolic and diastolic values of each measure). Research results shows that, regarding both systolic and diastolic blood pressures, there were statistically significant differences between the average of total measurements(n) and the averages of n-1, n-2 and n-3 measurements which were calculated with the elimination of first, early morning and last measures from total daily measurements.( p<0.001 for all systolic and diastolic comparisons). The ones with systolic blood pressure < 140 mmHg (n=256) at the first measurement of monitoring were according hypertensive according to the total average (>135 mmhg, n=43, 16.8%), whereas hypertension ratio in the ones with systolic blood pressure > 140 mmHg (n=269) at the first measurement was (n=153, 56.9%). Research results suggest that, the first measurement > 140 mmHg increases the probability of hypertension by 3.4 times when compared with those whose first measurement being < 140 mmHg.

Keywords: Ambulatory blood pressure monitoring Hypertention