Association of systolic blood pressure time in target range and all-cause mortality in patients with atherosclerotic cardiovascular disease: an analysis of a prospective cohort study

Objectives To investigate the association between systolic blood pressure time in target range (SBP-TTR) and the risk of all-cause mortality in patients with atherosclerotic cardiovascular disease (ASCVD). Design Analysis of data from a prospective cohort. Setting This study used data from the Kailuan Study. Participants diagnosed with ASCVD from 11 hospitals affiliated with the Kailuan Group in Tangshan, China were included in the analysis. Participants We included 6732 participants who developed ASCVD between 1 July 2006 and 31 December 2013, and who had two or more blood pressure measurements recorded between the ASCVD diagnosis date and 31 December 2017. All participants were followed up until 31 December 2022. Outcome measures SBP-TTR was defined as the proportion of time during which SBP remained within the target range, calculated using the linear interpolation method. Participants were stratified into five SBP-TTR categories: 0%, >0% to <25%, 25% to <50%, 50% to <75% and ≥75%. Associations between SBP-TTR categories and all-cause mortality were evaluated. Results When the target SBP range was defined as 120–140 mm Hg, compared with the SBP-TTR=0% group, the multivariable-adjusted HRs (95% CIs) for all-cause mortality were 0.92 (0.78 to 1.07), 0.82 (0.72 to 0.94), 0.79 (0.68 to 0.92) and 0.76 (0.65 to 0.89) for the SBP-TTR groups of <25%, 25% to <50%, 50% to <75% and ≥75%, respectively. For each SD increase in SBP-TTR, the risk of all-cause mortality decreased, with a multivariable-adjusted HR of 0.90 (95% CI 0.85 to 0.95). The inverse association between SBP-TTR and all-cause mortality was more pronounced in younger participants (aged <67 years) (p for interaction=0.008). Conclusions This study demonstrated a significant inverse association between SBP-TTR and all-cause mortality among patients with ASCVD. The association between maintaining SBP within the 120–140 mm Hg target range and reduced mortality was more evident in younger individuals. These findings suggest that sustained and stable blood pressure control may improve long-term survival in patients with ASCVD. Trial registration number ChiCTR-TNC-11001489.