Association Between Documented Hypertension and In-Hospital Mortality Among Critically Ill Adults: A Retrospective Cohort Study Using the Medical Information Mart for Intensive Care IV Database

Background Hypertension is one of the most common chronic conditions worldwide and is frequently encountered among patients admitted to ICUs. Although hypertension is a well-established risk factor for cardiovascular morbidity and mortality, its association with outcomes among critically ill patients remains incompletely understood. Objective To determine whether documented hypertension is associated with in-hospital mortality among critically ill adults admitted to ICUs. Methods This retrospective cohort study used data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) version 3.1 database. Adult patients aged 18 years and older with a first ICU admission were included. Hypertension was identified using International Classification of Diseases, Ninth Revision (ICD-9), and Tenth Revision (ICD-10) diagnostic codes. The primary outcome was in-hospital mortality. Multivariable logistic regression was used to evaluate the association between hypertension and mortality after adjustment for age, sex, race or ethnicity, Charlson Comorbidity Index (CCI), Sequential Organ Failure Assessment (SOFA) score, and mechanical ventilation. A sensitivity analysis was performed using the Oxford Acute Severity of Illness Score (OASIS). Results A total of 65,339 critically ill adults were included in the final analysis, of whom 41,193 (63.1%) had documented hypertension. In-hospital mortality occurred in 7,078 patients (10.8%). Patients who died were older and had higher CCI, SOFA, and OASIS values than survivors (all p < 0.001). After adjustment for potential confounders, hypertension was associated with lower odds of in-hospital mortality (adjusted OR, 0.67; 95% confidence interval, 0.63 to 0.71; p < 0.001). Higher age, CCI, SOFA score, and mechanical ventilation were associated with increased odds of mortality. Similar findings were observed in the sensitivity analysis using the OASIS (adjusted OR, 0.70; 95% CI, 0.66 to 0.74; p < 0.001). Conclusion Documented hypertension was associated with lower odds of in-hospital mortality among critically ill adults after adjustment for demographic and clinical characteristics. Comorbidity burden, illness severity, and mechanical ventilation remained important factors associated with mortality. Further studies are needed to examine the influence of hypertension severity, blood pressure control, and treatment patterns on outcomes among critically ill patients.