Kawasaki Disease Incidence in Children and Adolescents: an Observational Study in Primary Care

Background: Kawasaki disease is reported to be increasing in incidence and is the commonest childhood cause of acquired heart disease in the Western world.

Aim: To determine the current UK incidence of Kawasaki disease across childhood and adolescence; and investigate trends over time and season.

Design And Setting: An observational, descriptive study in the UK.

Method: The Health Improvement Network (THIN) database of primary healthcare records was searched for codes or text indicating Kawasaki disease. Identified records were compared with a study case definition and a date of onset was assigned to cases. The incidence, age/sex distribution, and trend in seasonal and temporal distribution were estimated (2008-2012).

Results: A total of 110 episodes of Kawasaki disease in 109 children were identified from 3.9 million person-years observation. The incidence of Kawasaki disease was 2.8 per 100 000 person-years (95% confidence interval [CI] = 2.3 to 3.4) when aged <20 years; 9.1 (95% CI = 7.3 to 11.2) aged <5 years, and 3.0 per 100 000 (95% CI = 2.0 to 4.3) across the age groups when possible cases were included. More cases were identified in males (55%) with one-fifth of cases diagnosed after 5 years of age. There was no statistically significant trend in incidence over the study years (P = 0.10 adjusted for sex and month), or between seasons (P = 0.65 adjusted for year and sex).

Conclusion: Although the incidence of Kawasaki disease remains low and has stabilised in the UK, GPs should recognise that the condition occurs throughout childhood and across the seasons.