Correlation between blood albumin and hospital death and long-term death in ICU patients with heart failure: data from the medical information mart for intensive care III database

BACKGROUND: Elevated circulating levels of albumin (ALB) are often associated with improved prognosis in patients with heart failure (HF). However, investigations of its association with hospital death and long-term death in HF patients in the intensive care unit (ICU) are limited. AIM: We examined whether increased blood ALB levels (first value at admission and maximum and minimum values in the ICU) were related to a greater risk of hospital death and long-term death in ICU patients with HF. METHODS: For the first time, we analyzed 4084 ICU patients with HF admitted to the ICU in The Medical Information Mart for Intensive Care III (MIMIC-III) database. RESULTS: Among 4084 HF patients, 774 (18.95%), 1056 (25.86%) and 1720 (42.12%) died in the hospital, within 30 days and 1 year, respectively. We conducted a logistic regression analysis and found significant inverse associations between blood ALB concentration and risk of hospital death, 30-day death and 1-year death when the covariates including age, sex, myocardial infarction (MI), hypertension, diabetes, valvular diseases, atrial fibrillation, stroke and chronic kidney disease (CKD) were adjusted. We additionally used a smooth curve for univariate analysis to establish an association between blood ALB concentration and death risk. Surprisingly, we observed U-shaped correlations between blood ALB concentration and hospital mortality, 30-day mortality and 1-year mortality. We found that the "inflection point" for the blood ALB concentration at the lowest risk of death was 3.5 g/dL. We further observed that a higher blood ALB concentration (albumin-max) did not contribute to a reduced risk of death (hospital death, 30-day death and 1-year death) in HF patients with an albumin concentration >3.5 g/dL. CONCLUSIONS: A lower blood ALB concentration contributed to a greater risk of hospital death and long-term death in HF patients admitted to the ICU, further suggesting that nutritional support in the ICU is highly important for improving the short-term and long-term mortality of HF patients. However, in HF patients without hypoproteinaemia (>3.5 g/dL), the impact of increased serum ALB on patient prognosis still needs to be demonstrated.