All participants were asked by study staff at follow-up visits if they had attended hospital at any point after enrolment. Study staff also looked for evidence of hospitalisations when abstracting from clinic files. For each participant with a recorded hospitalisation and for all participants who were recorded as having died after enrolment, the study team manually searched the admission records of the surrounding public hospitals and reviewed clinical notes when they could be located. The National Health Laboratory Service (NHLS) database was additionally searched and the results of investigations recorded. Data were abstracted by a member of the study team (doctor or professional nurse) using standardized paper forms. Ascertainment of death was done as part of the main trial. 

Records of participants’ hospitalisation were maintained in a password-protected Microsoft Excel workbook. Anonymized data from hospital files and the NHLS database were maintained in EpiData (Epidata Association, Odense, Denmark) databases.