Register study of migrants' hospitalization in Norway: world region origin, reason for migration, and length of stay

Background: The proportion of migrants and refugees increase in many populations. Health planners have to consider how migration will influence demand for health care. This study explores how migrants' geographical origin, reason for migration, and duration of residence are associated with admission rates to somatic hospitals in Norway.

Methods: Sociodemographic information on all individuals residing in Norway at the start of 2008 was linked to data on all admissions to somatic hospitals during 2008-2011. Migrants, age 30-69, who had come to Norway during 1970-2007 (N = 217,907), were classified into seven world region origins and compared with native Norwegians of the same age (N = 2,181,948). Any somatic hospital stay 2008-2011 and number of hospital admissions 2008-2011 per 1000 personyears for a set of somatic diagnoses were analyzed by age and gender standardized rates, linear probability models, and Poisson regression.

Results: In the native Norwegian sample, 28.7 % had at least one admission 2008-2011, and there were 116 admissions per 1000 personyears. Corresponding age and gender adjusted figures for the migrant sample were 27.0 % and 103 admissions. Admission rates varied with migrants' geographical origin, with relatively many admissions among migrants from West and South Asia and relatively few admissions among migrants from Western, East European, and Other Asian countries. Hospitalization varied strongly with reason for migration, with low admission rates for recent work migrants and high admission rates for recent refugees. Admission rates tended to move towards the level among native Norwegians with increasing length of stay. Among longstanding migrants (arrival period 1970-1989), admission rates were close to the levels of native Norwegians for most analyzed migrant categories.

Conclusion: Both world region origin, reason for migration, and duration of residence are important sources for variations in migrants' utilization of somatic hospitals. Forecasts about migrants' use of hospital services have to take into account how the migrant population is composed as to these three determinants. High admission rates among recently arrived refugees should be a health policy concern.