Statistical Analysis
For descriptive analysis, we compared the baseline characteristics of
the patients who had 3 or more EF measurements versus fewer than 3
measurements. Normally-distributed continuous variables were compared
with t-test. Categorical variables were compared with chi-square test.
We categorized the study population into two groups based on whether
their follow-up EF measurements were >35% or ≤35%.
Subgroup analyses were performed among patients with ischemic and
non-ischemic cardiomyopathy and those with normalized EF. In additional
analyses, we also categorized the study population into three groups
based on their follow-up EF measurements. Patients who had a
>10% increase in EF were categorized as improved, those
with a >10% decrease in EF were categorized as reduced,
and patients with <10% change in EF in either direction were
categorized as unchanged. We performed sensitivity analyses using
>5% cutoff instead of 10%. Unadjusted logistic regression
was used to comparing ischemic and non-ischemic proportions at first
follow up. All analyses were performed using SAS (SAS Institute) version
9.4. A p value < 0.05 was accepted as significant.