Cohort follow-up using computer linkage with routinely collected data

Abstract

The validation of a computerised record linkage system for matching members of a defined cohort with routinely collected national data sources is reported for the first time. The two national sources relate to mortality and inpatient data and provide contrasting characteristics in their method of collection. The linkage system produces a group of possible matches based on identifying information restricted to surname, initials, sex and date of birth which, with a clerically assisted scrutiny, gives levels of sensitivity of 66% for the mortality and 81% for the inpatient data. Specificity can be increased to 100% if conventional follow-up methods are used for the limited set of matches classified as probable by the clerical scrutiny.