Table 2: Definitions for outcomes of interest.

All-cause mortalityDeaths due to any cause except suicide.

Cardiac mortalityBased on death certificates with ICD 10 codes I10, I11.9, I20, I21, I22, I23, I24, I25, I42.8, I42.9, I46, I47, I49.0, I49.8, I49.9, I51.6, I51.9, I70.9, R09.2, R96, R98

SCD primary definitionThis was a narrow definition of SCD and the most restrictive. The SCD diagnosis was derived from the following ICD10 codes recorded on death certificates (available for January 1998 to November 2010): I46, I47.2, I49.0, R09.2, R96 [19], from Read codes in GPRD that correspond to these ICD10 codes, or from free text in the ±3 weeks before or after the death recording. Data from a national registry of hospital admission (Hospital Episode Statistics [HES], available for April 1997 to October 2010) were used to ensure that the event took place outside the hospital. A mortality event that occurred within 30 days after the hospital discharge date was not included in the SCD definition.

SCD secondary definitionThis definition is broader than the primary definition and is similar to the definition used by Ray et al. (2009) [4]. The SCD diagnosis was derived from death certificates with ICD 10 codes I10, I11.9, I20, I21, I22, I23, I24, I25, I42.8, I42.9, I46, I47, I49.0, I49.8, I49.9, I51.6, I51.9, I70.9, R09.2, R96.1, R98, from Read codes in GPRD that correspond to these ICD10 codes, or from free text in the ±3 weeks before or after the death recording. Cases with a HES record of hospitalisation were excluded.

SCD tertiary definitionThis definition was the same as the secondary definition with the exception that only data from GPRD and not from death certificates or HES were used.

SCD (based on free text)The following text strings were used to identify sudden cardiac death from GPRD free text: “dropped dead,” “died unexpectedly,” “sudden cardiac death,” “death” and “cause unknown,” “acute cardiac death,” “unexpected” and “death,” “mors subita,” “death instanta,” “died instanta,” “sudden death,” “dropped dead,” and “died suddenly.”

CHDBased on GPRD Read codes; data from a national registry of hospital admission (Hospital Episode Statistics (HES) ICD10 codes I21 or I22; or cardiac procedures)

Life-threatening Ventricular arrhythmias Based on GPRD Read codes or HES ICD10 I49.0.