Creating a powerful platform to explore health in a correctional population: a record linkage study

We used record linkage to create a data repository of health information of persons who were federally incarcerated in Ontario and Canada. We obtained records from 56,867 adults who were federally incarcerated between January 1, 1998 and December 31, 2011 from the Correctional Service of Canada; 15,248 records belonged to individuals residing in Ontario, Canada. We linked these records to the Registered Persons Database (RPDB) which contained records from 18,116,996 individuals eligible for health care in Ontario. Out of 56,867 OMS records, 22,844 (40.2%) were linked to the RPDB. Looking only at those incarcerated in Ontario, 98%, (14 953 of 15248) records were linked to RPDB. Most records of persons in Ontario-based facilities were linked deterministically. Linkage rates were lower for women, minority groups, and substance users. In conclusion, record linkage enabled the creation of a valuable data repository: there are no electronic medical records for correctional populations in Canada, making it more difficult to profile their health.