Using interval rather than recorded blood pressures reduced cusum plot height and CDCAM by ~6%, altering CPS time by 1 h changed CDCAM by ~7%, and missing readings increased variation up to 13%.
How do variations in data quality and implementation parameters affect the cumulative sums (cusums) analysis of circadian blood pressure?
The implementation parameters and data quality of ambulatory blood pressure recordings significantly affect the results of cumulative sums analysis for circadian blood pressure.
The assessment of circadian blood pressure change by ambulatory blood pressure monitoring has potential as a predictor for cardiovascular events, but its evaluation is problematic due to the difficulty in defining day and night periods for individual subjects. The cumulative sums (cusums) method has the advantage of simplicity over mathematical modelling techniques and is reported to give more reproducible results than methods that use time-dependent sleep and wake periods. However, cusum parameters (cusum-derived circadian alteration magnitude (CDCAM) and cusum plot height (CPH)) are affected by the implementation of the method and by the quality of ambulatory blood pressure recordings. This study quantifies the effects of using interval blood pressure values, changing the time used for calculating the cusum plot slope (CPS) and using incomplete data recordings. Significant effects are reported in all cases. Using interval rather than recorded blood pressures causes a mean reduction in CPH and CDCAM of approximately 6%. Altering the CPS time by 1 h (from 6 h) results in a mean change in CDCAM of approximately 7%. In recordings with hourly readings, the coefficient of variation in CPH and CDCAM ranges from 4% (one missing reading) to 13% (five missing readings).
Burn et al. (Fri,) conducted a other in Circadian blood pressure. Variations in cumulative sums (cusums) method implementation vs. Standard implementation was evaluated on Cusum parameters (CDCAM and CPH). Using interval rather than recorded blood pressures reduced cusum plot height and CDCAM by ~6%, altering CPS time by 1 h changed CDCAM by ~7%, and missing readings increased variation up to 13%.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: