Simple and safe digitoxin dosing in heart failure based on data from the DIGIT-HF trial

Area of Science:

• Cardiology
• Pharmacology
• Clinical Trials

Background:

• Heart failure with reduced ejection fraction (HFrEF) is a significant cardiovascular condition.
• Cardiac glycosides, such as digitoxin, are used in HFrEF management.
• Optimizing digitoxin dosing is crucial for patient safety and efficacy.

Purpose of the Study:

• To develop a simple dosing score for initiating digitoxin therapy in HFrEF patients.
• To identify patient characteristics associated with the need for digitoxin dose reduction.
• To improve the safety and effectiveness of digitoxin treatment in HFrEF.

Main Methods:

• Utilized data from the randomized, double-blinded DIGIT-HF trial.
• Analyzed 317 HFrEF patients randomized to digitoxin for score derivation.
• Employed logistic regression and ROC curve analyses to identify predictors and optimal cut-points for dose reduction.
• Validated the score in an independent dataset of 64 patients.

Main Results:

• Factors associated with digitoxin dose reduction included female sex, age ≥ 75 years, BMI < 27 kg/m², and eGFR < 50 ml/min/1.73 m².
• A dosing score was developed where each of these factors assigned one point.
• A score of ≥ 1 indicated the need for dose reduction, achieving 81.6% sensitivity and 49.7% specificity in the derivation set.
• The score demonstrated good accuracy in the validation set (87.5% sensitivity, 37.5% specificity).

Conclusions:

• A simple dosing score can guide initial digitoxin therapy in HFrEF.
• Patients with female sex, age ≥ 75 years, BMI < 27 kg/m², or eGFR < 50 ml/min/1.73 m² should start digitoxin at 0.05 mg once daily.
• Other HFrEF patients may safely initiate digitoxin at 0.07 mg once daily.