Characteristics and Outcomes of Suspected Digoxin Toxicity and Immune Fab Treatment Over the Past Two Decades-2000-2020

The role of digoxin in clinical practice has narrowed over time. Data on digoxin toxicity trends and outcomes are variable and lack granularity for treatment outcomes. This study aimed to address data gaps in digoxin toxicity trends and outcomes in patients treated with or without digoxin immune fab (DIF). This single-center analysis examined patients with signs/symptoms concerning digoxin toxicity, defined as hospital admission or emergency department visit with elevated digoxin serum concentrations (>2 ng/ml) and/or a primary diagnosis code of digoxin toxicity and/or DIF order. Between 2000 and 2020, 727 patients were identified with signs concerning for digoxin toxicity with a mortality rate of 12.7% during admission and 42.7% at 1 year. DIF was ordered in 9% of cases. Incidence of digoxin toxicity per 1,000 patients with a digoxin prescription and frequency of DIF treatment fluctuated over time without a clear trend toward increase or reduction. DIF-treated patients demonstrated a heavier co-morbidity burden and lower presenting heart rates (median 53 [39.5 to 69.5] vs 77 [64.0 to 91.5] beats/min, p <0.001), worse renal function (median estimated glomerular filtration rate, 30.3 [14.8 to 48.6] vs 40.0 [24.2 to 61.2] ml/min/1.73 m², p = 0.013), and higher potassium (median 4.5 [4.0 to 5.3] vs 4.3 [3.9 to 4.8] mEq/L, p = 0.022). Compared with a matched cohort, DIF-treated patients experienced a nonsignificant, numerically lower in-hospital mortality (8.2% vs 15.8%, p = 0.199) and 30-day all-cause hospitalization (14.3% vs 24.7%, p = 0.112) and similar 6-month and 1-year hospitalization and mortality. In conclusion, digoxin toxicity remains a pertinent public health issue despite reduction in digoxin utilization. DIF therapy is used in a medically complex population with a high-acuity illness at presentation and is associated with nonsignificant trends toward reduced in-hospital mortality and early readmission that are attenuated over time.