Statistical analysis
Continuous variables were conveyed as a mean ± standard deviation and median with interquartile range (IQR), whilst categorical variables were presented as a number and percentage. Statistical analysis was performed using a Chi-squared test and an independent T-test. A p-value of <0.05 was considered significant. Lead longevity was analysed using the Kaplan-Meier model and risk factors were compared using a univariate, multi-variate and Cox regression analysis.