Relationship Between Primary Percutaneous Coronary Intervention, Door-to-balloon Times, and Mortality for Heart Attack Patients Across England

We described patient characteristics using percentages for categorical data, means and SD or medians and IQRs for normally and non-normally distributed continuous variables, respectively. Statistical comparisons for differences in baseline characteristics among patients admitted during regular hours and off-hours were performed using χ2 tests for categorical variables, t-tests and Wilcoxon rank sum tests for normally and non-normally distributed continuous variables, respectively. DTB times were described using median and IQR based on time of admission. All p values were calculated as two-tailed analyses, using a significance level of 5%.