Indiana University-Purdue University Indianapolis (IUPUI) / In 2009, Indianapolis Emergency Medical Service (I-EMS, formerly Wishard Ambulance Service) launched an electronic medical record system within their ambulances and started to exchange patient data with the Indiana Network for Patient Care (INPC). This unique system allows EMS personnel in an ambulance to get important medical information prior to the patient’s arrival to the accepting hospital from incident scene. In this retrospective cohort study, we found EMS personnel made 3,021 patient data requests (14%) of 21,215 EMS transports during a one-year period, with a “success” match rate of 46%, and a match “failure” rate of 17%. The three major factors for causing match “failure” were (1) ZIP code 55%, (2) Patient Name 22%, and (3) Birth Date 12%. This study shows that the ZIP code is not a robust identifier in the patient identification process and Non-ZIP code identifiers may be a better choice due to inaccuracies and changes of the ZIP code in a patient’s record.

Indiana University-Purdue University Indianapolis (IUPUI) / Identifying spatial and temporal patterns of disease occurrence by mapping the residential locations of affected people can provide information that informs response by public health practitioners and improves understanding in epidemiological research. A common method of locating patients at the individual level is geocoding residential addresses stored in electronic medical records (EMRs) using address matching procedures in a geographic information system (GIS). While the process of geocoding is becoming more common in public health studies, few researchers take the time to examine the effects of using different address databases on match rate and positional accuracy of the geocoded results. This research examined and compared accuracy and match rate resulting from four commonly-used geocoding databases applied to sample of 59,341 subjects residing in and around Marion County/ Indianapolis, IN. The results are intended to inform researchers on the benefits and downsides to their selection of a database to geocode patient addresses in EMRs.