Digoxin and 30-day all-cause hospital admission in older patients with chronic diastolic heart failure

Background In the main Digitalis Investigation Group (DIG) trial, digoxin reduced the risk of 30-day all-cause hospitalization in older systolic heart failure patients. However, this effect has not been studied in older diastolic heart failure patients. Methods In the ancillary DIG trial, of the 988 patients with chronic heart failure and preserved (> 45%) ejection fraction, 631 were age ≥ 65 years (mean age 73 years, 45% women, 12% non-whites), of whom 311 received digoxin. Results All-cause hospitalization 30-day post randomization occurred in 4% of patients in the placebo group and 9% each among those in the digoxin group receiving 0.125 mg and ≥ 0.25 mg a day dosage (P =.026). Hazard ratios (HR) and 95% confidence intervals (CI) for digoxin use overall for 30-day, 3-month, and 12-month all-cause hospitalizations were 2.46 (1.25-4.83), 1.45 (0.96-2.20) and 1.14 (0.89-1.46), respectively. There was one 30-day death in the placebo group. Digoxin-associated HRs (95% CIs) for 30-day hospitalizations due to cardiovascular, heart failure, and unstable angina causes were 2.82 (1.18-6.69), 0.51 (0.09-2.79), and 6.21 (0.75-51.62), respectively. Digoxin had no significant association with 30-day all-cause hospitalization among younger patients (6% vs 7% for placebo; HR 0.80; 95% CI, 0.36-1.79). Conclusions In older patients with chronic diastolic heart failure, digoxin increased the risk of 30-day all-cause hospital admission, but not during longer follow-up. Although chance finding due to small sample size is possible, these data suggest that unlike in systolic heart failure, digoxin may not reduce 30-day all-cause hospitalization in older diastolic heart failure patients.