How social and geographical backgrounds affect hospital admission with a serious condition: a comparison of 11 immigrant groups with native-born Norwegians

Background: The foreign-born population in Norway displays considerable diversity in terms of source country, socioeconomic status and settlement experience. This study assessed the consequences of this diversity for the risk of being admitted to hospital with a serious condition. To what extent could variations between immigrant and native-born hospitalisation patterns be accounted for by variations in income, education and residential area characteristics? Methods: The study linked information on socioeconomic and geographical level-of-living factors involving 2,820,283 individuals between 20 and 69 years old to hospital admissions recorded in Norway’s National Patient Registry. Immigrants from 11 of the most frequently represented countries were included. The outcome variable consisted of a selection of relatively serious diagnoses (neoplasms and endocrine, circulatory and respiratory diseases), totalling 548,140 admissions from 2008 to 2011. Age- and gender-adjusted admission rates were analysed using a Poisson regression. Results: The adjustments for income and education reduced the hospitalisation rates of almost all immigrant groups. The groups whose previous rates were above native-born rates moved towards the Norwegian reference, whereas groups that initially had lower age- and gender-adjusted rates compared with the Norwegian-born population increased the distance to the Norwegian reference. The risk of hospitalisation among most immigrant groups decreased compared with the Norwegian-born population when their income and educational levels were accounted for. Particularly, immigrants with lower levels of income or education tended to have relatively low hospitalisation rates, indicating the possibility of a healthy immigrant effect. While many immigrant groups used less somatic healthcare than the native-born population did, higher educational or income levels did not prevent hospitalisation to the same extent as they did for the native-born population. Conclusions: Although adjustments for socioeconomic factors tended towards lower hospitalisation rates for most immigrant groups, the adjustments did not reduce the considerable variations among individual countries