Potentially avoidable hospitalizations in five European countries in 2009 and time trends from 2002 to 2009 based on administrative data

Introduction: Potentially avoidable hospitalizations in chronic conditions are used to evaluate health-care performance. However, evidence comparing different countries at small geographical areas is still scarce. The aim of the present study is to describe and discuss differences in rates and time-trends across health-care areas from five European countries. Methods: Observational, ecological study, on virtually all discharges produced in five European countries between 2002 and 2009. Potentially avoidable hospitalizations were operationally defined as a joint indicator composed of six chronic conditions. Episodes flagged as potentially avoidable were allocated to 913 geographical health-care areas. Age-sex standardized rates and standardized hospitalization ratios, as well as several statistics of variation, were estimated. Results: Four hundred sixty-two thousand seven hundred and ninety-two episodes were flagged as potentially avoidable. Variation in rates across countries was notable, from 93.7 cases per 10 000 inhabitants in Denmark to 34.8 cases per 10 000 inhabitants in Portugal. Within-country variation was also noteworthy, from 3.12 times among extreme areas in Spain to a 1.46-fold difference in Denmark. The highest systematic variation was found in Denmark (empirical Bayes 0.45) and the lowest in England (empirical Bayes 0.08). Rates and systematic variation remained fairly stable over time, with Denmark and England experiencing a statistically significant decrease (20% and 10%, respectively). Income and educational level, hospital utilization propensity, and region of residence were found to be associated with avoidable admissions. Conclusion: The dramatic variation across countries, beyond age and sex differences, and its consistency over time, implies systemic, although differential, behaviour of the five health-care systems with regard to chronic care