In order to distinguish this from knowledge transfer, Ellis et al. (2011: 1261) stress that "[t]ransfer theory concerns intraperson (or intragroup or intraorganizational) transfer of practices and routines".
Participants were censored at the first of any of the 12 different vascular events, transfer out of practice, death, or last collection date of practice.
The end of this observed time period was defined by the earliest of; date of death, date of transfer out of practice, 31st August 2010 (end of matched HES data in current linkage) or the last collection date for the practice.
The primary outcome of interest was all cause mortality as identified by codes for death or for transfer out of practice due to death in the General Practice Research Database.
Follow-up information for each patient was based on data from the index date (inclusive) to the end of patient records (earliest date of patient transfer out of practice and practice last data collection date).
Participants were censored at the first diagnosis of peripheral arterial disease (either in primary care, in secondary care, or by mortality), transfer out of practice, death, or last collection date of practice.
Only data for the periods during which patients were 'actively' registered with practices were included in analyses (i.e. we used data from current registration date up to the date of last data collection, transfer out of practice or death).
Right censoring occurred at the earliest of six months after recording of pneumonia, death, or the end of the observation period (transfer out of practice or last data collection date).
However, inclusion criteria for CPRD-based studies are generally patient-based rather than practice-based, and include all individual patients with UTS data for the analysis period (ie, from diagnosis date to end of study, death or transfer out of practice), and on this basis 61 458 patients from 577 CPRD practices could be included.
Statin exposure was used as a time-varying covariate, with the period of exposure from the date of first prescription to when the statin was stopped (estimated as the date of last prescription plus 90 days; intervening breaks in the use of statins were ignored), or if not stopped until the end of the study period, date of death or date of transfer out of practice.
