Statistical Analyses
Continuous variables were given as mean ± SD or median and interquartile
range (IQR) as appropriate. Categorical variables are presented as
percentages. Patterns of distribution of continuous variables and
equality of variances across groups were tested with Shapiro-Wilk and
Levene tests, respectively. For continuous variables, either one-way
ANOVA test with Welch correction or Kruskal-Wallis tests were used
depending on the presence of normal distribution pattern. Post-hoc
analyses for variables with a normal distribution were done using
Tukey’s HSD or Games-Howell tests; for the remaining post-hoc analyses
Dwass-Steel-Critchlow-Fligner test was used. For categorical variables,
chi-square test was used for comparisons. Kaplan-Meier curves were drawn
for survival analysis, and individual groups were compared with log-rank
test. Cox proportional hazards model was used to determine individual
predictors of one-year mortality. All parameters that had ap value
<0.10 on univariates Cox regression were included in the
initial model, and a backwards selection criterion was used to construct
the final model. Receiver-operator curves were drawn to analyze the
predictive accuracy of ACEF-MDRD for prediction of one-year mortality.
Additionally, DeLong’s test was used to determine whether ACEF-MDRD is
noninferior to GWTG-HF score in terms of accuracy. Net reclassification
improvement index (NRI) was calculated as described before [19]. For
all analyses, a p value of <0.05 was accepted as statistically
significant. All statistical analyses were done using Jamovi (The jamovi
project (2020). jamovi version 1.2 for Microsoft Windows), which is a
graphical user interface for R language (R Core Team (2019). R: A
Language and environment for statistical computing. Version 3.6 for
Microsoft Windows) and SPSS 25.0 (IBM Inc, Armonk, USA).
To avoid data loss in Cox regression and DeLong’s test, a multiple
imputation procedure was used to predict missing values. A total of 5
imputations were done and results from a pooled estimate of these 5
imputations were given as the result whenever possible. For all other
statistical tests, original data was used and number of cases in whom
data was available was indicated in parentheses.