101. Impact of various night-time period definitions on nocturnal ambulatory blood pressure
- Author
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Janis M. Nolde, Graham S. Hillis, Emily Atkins, Amy Von Huben, Simone Marschner, Justine Chan, Christopher M. Reid, Mark R. Nelson, Gemma Figtree, John Chalmers, Tim Usherwood, Anthony Rodgers, Clara K. Chow, and Markus P. Schlaich
- Subjects
Physiology ,Systole ,Hypertension ,Internal Medicine ,Humans ,Blood Pressure ,Blood Pressure Monitoring, Ambulatory ,Cardiology and Cardiovascular Medicine ,Circadian Rhythm - Abstract
Several definitions of night-time BP exist for the calculation of nocturnal blood pressure (BP) based on 24-h BP measurements. How much these methods differ regarding the resulting nocturnal blood pressure values, under which circumstances these differences become clinically meaningful, and under which circumstances diary-adjusted measurements should be used preferentially remains uncertain.Data of 512 24-h BP recordings were analysed regarding differences in nocturnal BP based on three alternative definitions of night-time: 2300-0700 h, 0100-0500 h, and diary-adjusted measures.Mean systolic nocturnal BP between 2300-0700 h was 2.5 mmHg higher than between 0100 and 0500 h and 1.6 mmHg higher than diary adjusted estimates. Up to 38.3% of individuals showed BP differences of more than 5 mmHg when comparing temporal definitions of night-time, resulting in significant proportions of individuals being re-classified as hypertensive. When diary-derived sleeping patterns differed by less than 2 h from the 2300 to 0700 h fixed time definition, mean BP discrepancies remained below 3 mmHg. Absolute time discrepancies between diary and 2300-0700 h fixed time definition of 2-4, 4-8 or at least 8 h led to SBP/DBP differences of 4.1/3.1, 6.8/6.1, and 14.5/9.1mmHg, respectively.Average differences of nocturnal BP between varying definitions in study/cohort data are small and would be of limited relevance in many settings. However, substantial differences can be observed in individual cases, which may affect clinical decision-making in specific patients. In patients whose sleeping patterns differs by more than 2 h from defined fixed night-times, diaries should be used for adjustment.
- Published
- 2022