Obesity and 1-year All-cause Survival of Adult Intensive Care Patients with Heart Failure: Data from the MIMIC-IV

Background: Heart failure is a disease that threatens global public safety. In recent years, the obesity paradox has been studied in cardiovascular disease and other fields. With the progress of aging, metabolic changes and regulation of fat function, it also provides many bridges for the dialogue between disease and molecular metabolism. The purpose of this study is to investigate the effect of obesity on the outcome of adult intensive care patients with heart failure combined with age factors.

Method: Data were derived from the fourth-generation Medical Information Marketplace for Intensive Care (MIMIC-IV version2.1) using structured query language on the Navicat (12.0.11) platform. People were divided into two groups based on the body mass index (BMI), one group with BMI ≥ 30 kg/m² and another group with BMI < 30 kg/m². Afterwards, the patients were divided into two subgroups based on their ages. One group included patients aged<60, and the other included patients aged ≥ 60. The extracted information includes demographic characteristics, laboratory findings, comorbidities, scores. Main results included in-hospital mortality, ICU mortality, and 1-year mortality. Secondary outcomes included hospital interval and ICU interval, use of renal replacement therapy, and rates of noninvasive and invasive ventilation support.

Result: In this cohort study, 3390 people were in the BMI<30 group, 2301 people were in the BMI ≥ 30 group, 960 people were in the age<60 group, and 4731 people were in the age ≥ 60 group, including 3557 patients after propensity score matching in high age group. Among patients aged ≥ 60, BMI ≥ 30 group vs. BMI<30 group showed significantly lower in-hospital mortality (13% vs. 16%) and one-year mortality (41% vs. 55%), respectively. Neither primary nor secondary outcomes were significantly described in the competition among patients aged under 60. Restricted cubic spline reveals a J-shaped nonlinear association between BMI and clinical endpoints within the entire cohort. Kaplan-Meier curves revealed a survival advantage in BMI ≥ 30 group (p < 0.001). Following age stratification, a beneficial effect of BMI categories on one-year mortality risk was observed in heart failure patients aged ≥ 60 (Univariable HR, 0.71, 95% CI, 0.65-0.78, p < 0.001; Multivariable HR, 0.74, 95% CI, 0.67-0.81, p < 0.001), but not in those under 60 years old.

Outcome: In ICU patients with heart failure, obesity offers a survival benefit to those aged ≥ 60. No obesity paradox was observed in patients younger than 60 years old. The obesity paradox applies to patients aged ≥ 60 with heart failure.