Background:
Quality improvement efforts have focused on reducing interstage mortality for infants with hypoplastic left heart syndrome (HLHS). In 2016 two publications reported that digoxin use was associated with reduced interstage mortality. The degree to which these findings have affected real world practice has not been evaluated.
Methods:
A multicenter retrospective cohort study of rates of digoxin prescription at discharge was performed of neonates with HLHS surviving to discharge without transplant from 1/2006-12/2018 at PHIS hospitals. A difference in difference analysis was performed using mixed effects models to adjust for measurable covariates (known arrhythmia, prematurity, renal insufficiency, etc.) with the hypothesis that the likelihood of digoxin prescription increased after 1/2016. Inter-hospital practice variation was measured, calculating the median odds ratio (MOR). Likelihood of furosemide and aspirin prescriptions were studied as falsification tests.
Results:
Over the study period 6091 subjects from 35 hospitals were included. Likelihood of receiving digoxin, furosemide, and aspirin are depicted (Figure). After adjusting for measurable covariates, discharge after 1/2016 was associated with increased odds of receiving digoxin (OR: 3.9, p<0.001). No association was seen between date of discharge and furosemide (p=0.26) or aspirin (p=0.12). Prior to 1/2016, the likelihood of receiving digoxin was decreasing (OR: 0.9 per year, p<0.001), while after 1/2016 the likelihood has increased (OR: 2.4 per year, p<0.001). Significant inter-hospital variation in the likelihood of receiving digoxin was seen (MOR=3.5, p<0.001 with no significant difference before and after 2016).
Conclusion:
The use of digoxin increased after publication of data about potential benefit in the interstage period. However, despite concerted quality improvement efforts, there is persistent large magnitude inter-hospital variation in practice.