Systolic Blood Pressure Time in Target Range Among Patients in Coronary Care Unit (CCU): A Retrospective Analysis

Objective: The research aimed to illustrated the prognostic value of systolic blood pressure time in target range (SBP-TTR) calculated by continuously monitoring blood pressure (BP) records among patients admitted to coronary care units. Methods: Data from the Medical Information Mart for Intensive Care-IV database was used in this retrospective cohort study. Systolic blood pressure (SBP) target ranges were defined as 110-140mmHg for awake time, and 90-120mmHg for sleep time, respectively. SBP-TTR was calculated as the proportion of measured SBP in the target range among all SBP measurements, and participants were divided into four groups according to the quartiles of TTR. We used Cox proportional hazard regression models to assess the association between SBP-TTR and one-year all-cause mortality. Results: A total of 4757 patients with 400,289 BP records were included in the study. During a maximum of 365 follow-up days, the cumulative incidence of all-cause death diminished with the increase of TTR quartiles. After multivariable adjustment, comparing with the lowest quartile, the highest quartile of SBP-TTR showed significantly decreased risk on one-year mortality (HR:0.45, 95%CI: 0.32-0.63, P<0.0001), and 10% increment of TTR was associated with 13% decrease of all-cause mortality (HR:0.87, 95%CI: 0.84-0.90, P<0.0001). In sensitive analyses, both awake and sleep SBP targets were reset to wider ranges, and the results remained robust. Subgroup analyses generated consistent results across different demographic characteristics, baseline BP levels and comorbidities. Conclusions: There was a negative association between SBP-TTR and one-year all-cause mortality in CCU patients.