Quantification of NSW Ambulance Record Linkages with Multiple External Datasets.

This study has two aims: 1) to describe linkage rates between ambulance data and external datasets for "episodes of care" and "patient only" linkages in New South Wales (NSW), Australia; and 2) to detect and report any systematic issues with linkage that relate to patients, and operational or clinical variables that may introduce bias in subsequent studies if not adequately addressed. During 2010-11, the Centre for Health Record Linkage (CHeReL) in NSW, linked the records for patients attended by NSW Ambulance paramedics for the period July 2006 to June 2009, with four external datasets: Emergency Department Data Collection; Admitted Patient Data Collection; NSW Registry of Births, Deaths and Marriages death registration data; and the Australian Bureau of Statistics mortality data. This study reports linkage rates in terms of those "expected" to link and those who were "not expected" to link with external databases within 24 hours of paramedic attendance. Following thorough data preparation processes, 2,041,728 NSW Ambulance care episodes for 1,116,509 patients fulfilled the inclusion criteria. The overall episode-specific hospital linkage rate was 97.2%. Where a patient was not transported to hospital following paramedic care, 8.6% of these episodes resulted in an emergency department attendance within 24 hours. For all care episodes, 5.2% linked to a death record at some time within the 3-year period, with 2.4% of all death episodes occurring within 7 days of a paramedic encounter. For NSW Ambulance episodes of care that were expected to link to an external dataset but did not, nonlinkage to hospital admission records tended to decrease with age. For all other variables, issues relating to rates of linkage and nonlinkage were more indiscriminate. This quantification of the limitations of this large linked dataset will underpin the interpretation and results of ensuing studies that will inform future clinical and operational policies and practices at NSW Ambulance.

Robust data to close the gap: current vascular and maternal/newborn indicators as measures of progress in Aboriginal health in New South Wales.

OBJECTIVE: Focussing on maternal/newborn health and vascular diseases, to review NSW Health's reporting, by Aboriginal status, against national performance indicators relevant to preventable chronic diseases. METHODS: We reviewed seven indicator documents and the Australian Institute of Health and Welfare Chronic Disease Indicator Database to identify national indicators. Indicators from six NSW Health reports were then compared with these national indicators to assess reporting by Aboriginal status and region. RESULTS: NSW Health routinely reports against six maternal/newborn indicators and fourteen vascular national indicators. Five of the former report performance by both Aboriginal status and region. Eight of the latter report by Aboriginal status, one of which (diabetes hospitalisations) also reports by region. Indicator quality and breadth was substantially limited by under-enumeration of Aboriginal status, small or potentially unrepresentative samples, inadequate longitudinal or regional data and few primary health care indicators. Notwithstanding these limitations, we found wide and persistent disparities in outcomes for Aboriginal people for all indicators in all regions. CONCLUSIONS: NSW Health reports adequately, by Aboriginal status, for maternal/newborn health monitoring (albeit constrained by under-enumeration), but provides limited information about vascular health. A minimum, national chronic disease indicator dataset against which all jurisdictions would report performance by Aboriginal status and region is needed. Improved monitoring requires sustained efforts to address under-enumeration, better survey sampling, and population representative data from the primary care system.