International variation in clinical injury incidence: Exploring the performance of indicators based on health care, anatomical and outcome criteria
Objective: To analyse international variation in clinical injury incidence, and explore the performance of different injury indicators in cross-country comparisons. Methods: Hospital discharge data of seven European countries (Austria, Denmark, Ireland, Netherlands, Norway, England and Wales) were analysed. We tested existing and newly developed indicators based on (a) health care use, (b) anatomical criteria, or (c) expected health outcome: admissions excluding day-cases (a), hospital stay 4+ (a) and 7+ days (a), (serious) long-bone fractures (b), selected radiological verifiable fractures 'SRVFs' (b), and indicators based on international (Global Burden of Disease) and Dutch disability weights). Assessment criteria were reduction in incidence variation and length of stay in hospital, and the association between incidence and mortality rates. Results: Indicators based on health care use led to increased variation in incidence rates. Long bone fractures and SRVFs, and both indicators based on injuries with moderate to high disability showed similar variation in clinical incidence compared to the crude rates, smaller variation in median length of stay in hospital and a good association with mortality rates. Conclusion: No perfect or near perfect indicators of clinical injury incidence exist. For international comparisons, indicators based on disability weights, SRVFs and long bone fractures may be sensible indicators to use, in the absence of a direct measure of anatomical severity.