2.5. Statistical analysis
The primary outcome of the study was whether the presence of NOAF is a
risk factor for mortality in COVID-19. Secondary outcomes were the risk
factors associated with the development of NOAF. All categorical
variables are expressed as numbers and percentages, and continuous
variables were expressed as median and interquartile range (IQR).
Categorical variables between groups were compared with chi-square or
Fisher’s exact test, continuous variables were compared with
Mann–Whitney U -test. The independent effect of NOAF on hospital
mortality was assessed with multivariate logistic regression analysis.
To build the model, a purposeful selection method was used to select a
subset of covariates that were considered clinically important,
adjusting for confounders and statistical significance. An adjusted odds
ratio (OR) and a 95% confidence interval (CI) were reported for each
independent factor. A two-tailed P -value of < 0.05 was
considered statistically significant. Statistical analysis was performed
using SPSS (Statistical Package for the Social Sciences Version 24, IBM
Corp., Armonk, N.Y., USA)