Effect of Alzheimer Disease on Prognosis of Intensive Care Unit (ICU) Patients: A Propensity Score Matching Analysis

BACKGROUND: The growing number of patients with Alzheimer disease worldwide has become a leading public concern. Whether Alzheimer disease has an impact on the outcomes of critically ill patients remains unclear; therefore, we conducted this study to evaluate comorbid Alzheimer disease in patients in the Intensive Care Unit (ICU). MATERIAL/METHODS: Data were extracted from the Medical Information Mart for Intensive Care-III database, version 1.4. Patients were divided into an Alzheimer disease group and a non-Alzheimer disease group. Differences in all-cause mortality, length of hospital stay, mechanical ventilation rate, and mechanical ventilation duration were analyzed. Propensity score matching (PSM) was performed to compensate for differences in baseline characteristics. The differences in prognosis were compared between groups after PSM. Survival analyses in patients were performed and Cox regression analyses were used to predict prognoses. RESULTS: We included 33 935 patients, among which 433 patients were comorbid with Alzheimer disease. After PSM, there were no significant differences in 7-day mortality, but there were significant differences in 28-day mortality (P=0.047) and 90-day mortality (P=0.012) between the 2 groups. There was also a significant difference in the 4-year cumulative survival between the 2 groups (P<0.001). In all patients undergoing surgery, multivariate Cox regression analysis showed that Alzheimer disease comorbidity was significantly associated with 90-day mortality and 4-year mortality. CONCLUSIONS: Critical ill patients with Alzheimer disease had higher 28-day and 90-day mortality. Especially for patients undergoing surgery, Alzheimer disease is an independent risk factor affecting long-term survival.