Migration patterns driving threefold rise in Kawasaki disease cases in Sweden
A 32-year Swedish study found Kawasaki disease incidence in young children tripled from 1987 to 2018, driven largely by immigration from Asia and Africa. The finding signals healthcare systems must prepare for rising pediatric inflammatory disease in countries with changing demographics, affecting hospital capacity, specialist training, and public health planning.
Originaltitel: Patterns of migration underlie the increasing incidence of Kawasaki disease in Sweden from 1987 to 2018: a cohort study.
**Kawasaki-sjukdom ökar kraftigt bland barn med migrationsbakgrund i Sverige** Incidensen av Kawasaki-sjukdom hos barn under fem år tredubblade sig i Sverige mellan 1987 och 2018, från 3,6 till 12,1 per 100 000. En analys av 1 917 fall från nationella register visar att ökningen främst drivs av barn med en eller två föräldrar med icke-svensk, övervägande asiatisk eller afrikansk, ursprung. Karolinska Institutet och stockholmsbaserade barnkliniker kartlade diagnos, kön (62 procent pojkar) och föräldrarnas härkomst. Sjukdomen uppträdde oftare på vintern och våren. Två kraftiga toppar observerades 2008 och 2015, relaterade till svenskfödda föräldrars barn. Resultaten är kritiska för regionvårdens resursplanering. Inköpschefer och kliniker bör justera kapacitet för echokardiografi och inflammationsbiomarkörer i områden med högt andel migranter, och förbättra diagnostik bland högriskogrupper.
OBJECTIVE: To define the demographics of Kawasaki disease (KD) in Sweden during a 32 year period. METHOD: Routinely collected administrative and healthcare data from nationwide Swedish registers were collected for this population-based cohort study. The case definition was individuals under the age of 25 and diagnosed with KD from 1987 to 2018. Main measures included incidence rate, year and month of diagnosis, sex and age at diagnosis, patient's and parents' world region of birth, and home county. RESULTS: In total, 1917 cases were identified. Median age at diagnosis was 2.82 years (interquartile range 1.47-5.13) and 62% were males. Relative incidence rates in winter [1.29, 95% confidence interval (CI) 1.14-1.47] and spring (1.21, 95% CI 1.07-1.38) were higher than in the reference season (summer), while incidence over the study period varied geographically across counties, with no discernible pattern. The incidence rate in the population increased during the 32 year period from 3.6 to 12.1 (95% CI 9.1-15.2) per 100 000 under-5-year-olds during the last 5 years of the study. This increase related mainly to cases with one or two parents of non-Swedish, predominantly Asian and African, origin. Two significant peaks in incidence rates in 2008 and 2015 were also observed, mainly relating to cases with two Swedish-born parents. CONCLUSION: Our study confirms the age and sex distribution as well as seasonal variation and occurrence of peak years of KD. Migration patterns were associated with increasing numbers of KD, which is important to consider for healthcare planning and for defining risk groups.