Analysis of Intoxication, Rehospitalization, and One-year Survival of Heart Failure Patients Receiving Digoxin at Harapan Kita National Cardiovascular Center, Jakarta, Indonesia: A Cross Section-observational Study

Abstract

Background: Despite being the oldest therapy for heart failure, the use of digoxin is still controversial due to the narrow margin of safety. In Indonesia, digoxin is still considered one of the treatments for heart failure. However, analysis of intoxication has never been reported. This study aims to analyze the occurrence of digoxin intoxication, rate of rehospitalization and one-year survival in heart failure patients under digoxin treatment.

Methods: A cross section-observational study was conducted at Harapan Kita National Cardiovascular Centre from January 2017 to December 2018 on heart failure patients who received digoxin therapy and had data on serum digoxin level. Intoxication was defined as the presence of specific ECG alteration(s), at least one extra-cardiac symptom(s) and further classified as definite (serum digoxin >2 ng/mL), probable (serum digoxin 0.91-1.99 ng/mL), or possible (serum digoxin 0.5-0.9 ng/mL). Risk factors of intoxication were analyzed by Chi-square test, and one-year survival was analyzed with Kaplan Meyer method.

Results: 54 of 195 patients (27.69%) were classified as having intoxication, consisting of 32 (16.41%) definite, 19 (9.74%) probable, and 3 (1.54%) possible. Renal insufficiency was revealed as a significant influencing factor of digoxin intoxication with RR 2.48 (CI 1.13-5.464, p=0.016). Overall one-year survival of patients receiving digoxin was 259 days in the intoxication group and 307 days in the non-intoxication group. One-year rehospitalization was 11.8% in patients who received digoxin and 29.2% in those without digoxin (p=0.085).

Conclusion: The proportion of digoxin intoxication in heart failure patients was 27.69%. Renal insufficiency was revealed as a significant influencing factor of intoxication. There was a tendency of reduced hospitalization in those who received digoxin.

Keywords: Digoxin intoxication; heart failure; rehospitalization; risk factors; survival; treatment.