Correlation between blood pressure and mortality in older critically ill patients: Insights from a large intensive care unit database

Objectives: The study aimed to investigate the relationship between blood pressure (BP) levels and mortality among critically ill older adults in the intensive care unit (ICU), establish optimal BP target for this population, and assess the mediating effect of severe malnutrition on BP-related mortality. Methods: Data were extracted from the Medical Information Mart for Intensive Care IV version 2.2 database, focusing on critically ill patients aged 80 years and older. The analysis included various BP parameters, such as systolic BP (SBP), diastolic BP (DBP), and mean arterial pressure (MAP). Results: The study cohort comprised 14,660 critically ill patients, of whom 1558 (10.6 %) experienced ICU mortality and 2493 (17.0 %) experienced in-hospital mortality. Lower BP levels (SBP < 112 mmHg; DBP < 53 mmHg; MAP <65 mmHg), were associated with an increased risk of both ICU and in-hospital mortality. Notably, only reduced SBP levels were linked to a higher risk of 1-year mortality, with an adjusted hazard ratio 1.13 (95% confidence interval 1.05 to 1.23). Additionally, severe malnutrition was identified as a mediator in the relationship between low BP levels and ICU mortality, with BP levels positively correlated with prognostic nutritional indexes. Conclusion: Among critically ill older adults, lower BP levels are significantly associated with higher risks of ICU and in-hospital mortality, while reduced SBP levels are linked to 1-year mortality. These findings emphasize the importance of assessing nutritional status in older ICU patients with low BP levels to potentially mitigate mortality risk.