Baseline and Implant Encounter Characteristics
Patient demographic characteristics (age, sex, US region) were ascertained using data from the CMS enrollment file. Patient baseline comorbidities were defined as the presence of diagnosis and procedure codes on any encounter claim during the 12 months prior to implant (see full ICD-10 and CPT code list in Appendix 2 .) Comorbidities included end-stage renal disease (ESRD), renal dysfunction, coronary artery disease, peripheral vascular disease, tricuspid valve disease, atrial fibrillation, left bundle branch block, supraventricular tachycardia, ventricular arrythmia, steroid use, diabetes, heart failure, chronic obstructive pulmonary disease, hyperlipidemia, and hypertension. History of any cardiovascular events and procedures (acute myocardial infarction, coronary artery bypass graft, transcatheter aortic valve, and percutaneous coronary intervention) were also included. A Charlson Comorbidity Index (CCI) score was also calculated for each patient.7 Characteristics of the implant encounter hospitalization were also identified, including whether the implant occurred in the inpatient or outpatient hospital setting, whether the patient was admitted for the implant procedure hospitalization through the emergency department, whether the patient was implanted during the weekend, the time from admission to the implant procedure, and whether the patient had a concomitant cardiac procedure (transcatheter aortic valve replacement or atrial fibrillation ablation) during the pacemaker implant procedure.