January 1, 1995
View Full PaperAnalysis of twenty-four-hour ambulatory blood pressure monitoring: what time period to assess blood pressures during waking and sleeping?
Key Result
Compared with the diary method, the 9-hour sleeping period method overestimated systolic blood pressure during sleep by 3.74 mmHg (99% CI 2.70-4.77), whereas the 6-hour method was accurate.
Study Design
Type
Observational (n=95)
Structured PICO
Do fixed-period analysis methods of ABPM provide accurate estimates of waking and sleeping blood pressures compared to the diary method?
P
Population
95 ambulatory blood pressure monitoring recordings retrospectively analyzed to compare fixed-period and diary methods.
E
Exposure
Fixed-period analysis methods for ABPM (9-hour sleeping period from 2200 to 0700 h, and 6-hour sleeping period from 0100 to 0700 h)
C
Comparator
Diary method (waking and sleeping periods according to patient diary)
O
Outcome
Mean systolic and diastolic blood pressures during waking and sleepingsurrogate
A 6-hour fixed sleeping period (0100 to 0700 h) provides accurate estimates of sleeping blood pressure on ABPM, whereas a 9-hour period overestimates it and should be avoided.
Main Result
Mean Difference: 3.74 (95% CI 2.7–4.77)
Abstract
OBJECTIVE: To study whether two widely used methods of analysis of ambulatory blood pressure monitoring (ABPM), which calculate means for fixed periods, provide accurate estimates of blood pressure during the true waking and sleeping periods. DESIGN AND METHODS: Ninety-five ABPM recordings were retrospectively analysed. Mean systolic and diastolic blood pressures during waking and sleeping were calculated in three ways: the waking and sleeping period according to the diary of the patient (diary method); the waking period from 0700 to 2200 h and the sleeping period from 2200 to 0700 h (9 h); and the waking period form 1000 to 2300 h and the sleeping period from 0100 to 0700 h (6 h). RESULTS: Systolic and diastolic blood pressures during the waking period were not different among the three methods of analysis. Compared with the diary method, the 9 h sleeping period method overestimated systolic blood pressure during sleep by 3.74 mmHg 99% confidence interval (CI) 2.70-4.77 and diastolic blood pressure by 2.44 mmHg (99% CI 1.75-3.14). In contrast, there was no significant difference between the diary method and the 6 h sleeping period method. CONCLUSIONS: The 6 h sleeping period method gave accurate estimates of blood pressure during sleep. The use of the long (9 h) sleeping period method should be avoided in studies in which sleeping-waking differences will be part of the analysis.