Definition of Variables
A patient’s sex was categorized as male or female at the time of birth. Body mass index (BMI) was calculated as mass divided by the square of the height (kg/m2). A patient’s race was categorized as White, African American or Black, or other based on self-reported race within the electronic medical record. Duration of follow up was defined as the time elapsed between date of implantation to the last date of chart entry in a patient’s electronic medical record.