High-dose loop diuretic can raise post–cardiac surgery mortality

The study covered in this summary was published on ResearchSquare.com as a preprint and has not yet been peer reviewed.

Key takeaway

• High-dose furosemide after cardiac surgery is associated with increased mortality and other adverse outcomes.

Why this matters

• The influence of furosemide on prognosis after cardiac surgery is not fully understood.
• The current findings suggest that high-dose furosemide after cardiac surgery is associated with increased risk for death and other adverse events and therefore should be used cautiously in that setting.

Study design

• The retrospective cohort of 6,752 cardiac surgery patients was divided into two groups according to average daily furosemide dosage after cardiac surgery: less than 20 mg (low-dose group, n = 6,033) and at least 20 mg (high-dose group, n = 719).
• The group were compared for total furosemide dose, total furosemide dose of at least 200 mg, total dose of furosemide by patient weight, and average daily furosemide dose of at least 20 mg.
• The primary outcomes were in-hospital mortality and mortality at 1 year after cardiac surgery. Secondary outcomes were length of hospital stay of at least 14 days, length of ICU stay of at least 3 days, and mechanical ventilation for at least 48 hours.
• The study excluded patients aged younger than 18 whose weight data was missing or who had more than 5% of their data missing.

Key results

• Patients in the high-dose furosemide group tended to be older and have a higher body mass index (BMI) and higher rates of diabetes, chronic pulmonary diseases, heart failure, renal failure, blood transfusion, vasopressor use, and valvular surgery.
• They also tended have higher white cell counts and higher levels of blood urea nitrogen, creatinine, glucose, and lactate.
• Those in the high-dose group also were on vasopressors and ventilatory support longer.
• In adjusted multivariate analysis, increased in-hospital mortality was associated with average daily furosemide dose, average daily dose of at least 20 mg/d, and total dose of at least 200 mg.
• Increased mortality at 1 year was associated with total furosemide dose and average daily furosemide dose.
• Significant multivariate predictors of hospital stay of at least 14 days, length of ICU stay of at least 3 days, and mechanical ventilation for at least 48 hours after cardiac surgery included total furosemide dose, total dose by weight, average daily furosemide dose of at least 20 mg/d, and total dose of at least 200 mg.
• In subgroup analyses, average daily furosemide dose of at least 20 mg/d significantly increased risk for in-hospital mortality among patients younger than 60 years or with BMI of at least 28 who received vasopressors or blood transfusions, those with renal failure, and those with heart failure not involving congestion.

Limitations

• No limitations were discussed.

Disclosures

• The study was supported by grants from the National Natural Science Foundation of China, China Postdoctoral Science Foundation, and Jiangsu Postdoctoral Science Foundation.
• The authors declared that they have no competing interests.

This is a summary of a preprint research study, “Association between furosemide administration and outcomes in patients undergoing cardiac surgery,” from Jinghang Li, First Affiliated Hospital of Nanjing (China) Medical University, and colleagues on published on ResearchSquare.com. This study has not yet been peer reviewed. The full text of the study can be found on ResearchSquare.com. A version of this article first appeared on Medscape.com.