Increasing incidence of Kawasaki disease and associated coronary aneurysm in Aotearoa New Zealand: a retrospective cohort study.

BACKGROUND

Kawasaki disease (KD) is a childhood vasculitis which causes coronary artery aneurysms (CAA). There is a paucity of data regarding KD in Aotearoa New Zealand. We aimed to provide up-to-date epidemiological and clinical data about KD in the Auckland region.

METHODS

We conducted a retrospective population-based cohort study in the greater Auckland region between 2017 and 2021. Potential KD cases were identified from hospital discharge records, echocardiogram databases and intravenous immunoglobulin (IVIg) dispensing databases. Clinical records were reviewed and international diagnostic criteria were applied retrospectively.

RESULTS

A total of 161 cases of KD were identified (66.5% complete, 33.5% incomplete), with 84% aged under 5 years. Overall incidence (per 100 000/year under 5 years) was 20.4; this was highest in Asian (43.9) and Pacific (17.7) children. There was no significant difference in incidence between New Zealand European (10.1) and Māori (8.3) children. The mean yearly number of cases reduced during the start of the COVID-19 pandemic (37.6 vs 24.0, p=0.01). All children received at least one infusion of IVIg, with 20.5% receiving a second infusion. Twenty-seven children (16.9%) developed CAA. CAA was more common in children under 1 year, non-response to first dose of IVIg and Pacific children.

CONCLUSION

Incidence of KD and rate of CAA were higher than previously reported, although case numbers reduced during the COVID-19 pandemic. There was a high incidence of KD among Pacific children, who were most likely to develop CAA. Research focusing on strategies to identify and treat those at highest risk of CAA remains a priority.