Background: Digoxin is often used in long-term care (LTC) residents with heart failure despite a high risk of toxicity associated with increased age, comorbidities and polypharmacy. This toxicity may occur at serum digoxin concentrations that are as low as 1.54 nmol/L.
Objectives: To determine the prevalence of digoxin use, estimate the proportion at risk of toxicity and identify correlates of digoxin use in LTC residents with heart failure.
Methods: Cross-sectional survey in eight LTC facilities that lodge a total of 1223 residents.
Results: The prevalence of heart failure was 20%. Digoxin was prescribed for 32% of residents with heart failure and was associated with arrhythmia (primarily atrial fibrillation), anticoagulant and diuretic use, and higher serum thyroid-stimulating hormone. Digoxin doses higher than those that achieve the recommended therapeutic peak body stores of 6 microg/kg and 10 microg/kg were prescribed to 80% and 33% of residents with heart failure, respectively. Serum digoxin concentrations were greater than 1.5 nmol/L in 30% of patients. Comorbidities and concurrently prescribed medications that increase the risk of digoxin toxicity were prescribed to 26% of the patients.
Conclusions: Approximately one-third of LTC residents with heart failure received digoxin. Atrial fibrillation was the most important determinant of use. At least 26% of these residents were exposed to an increased risk of digoxin toxicity. Studies are required to determine safe and effective digoxin dosing regimens for frail elderly heart failure patients. Clinicians should exercise caution when using digoxin in LTC residents.