Incidence and short-term outcomes of Kawasaki disease

Objective — Kawasaki disease (KD) is a childhood vasculitis with conflicting reported North American trends in incidence and patient characteristics. Objectives: (1) determine KD incidence between 1995 and 2017; (2) compare patient characteristics by era and age group; (3) determine complication and cardiovascular follow-up rates.

Methods — We used population-based health administrative data to identify children (0–18 yr) hospitalized with KD in Ontario, Canada between 1995 and 2017. We excluded children with prior KD diagnosis or incomplete records. We determined the annualized incidence and follow-up trends.

Results — KD was diagnosed in 4,346 children between 1995 and 2017. Annual KD incidence was 22.0 (<5 yr), 6.1 (5–9 yr), and 0.6 (10–18 yr) per 100,000 children. KD incidence increased significantly for all age groups, including from 18.4 to 25.0 cases per 100,000 children <5 yr. Ninety-day mortality occurred in ≤5 children (≤0.1%). Coronary artery aneurysm (CAA) occurred in 106 children (2.4%, 95% confidence interval 2.0–2.9) during admission and 151 (3.5%, 95% confidence interval 3.0–4.1) during 11-year median follow-up. Children 10–18 yr had longer hospitalizations (4.3 vs. 3.5 days, p = 0.003) and more CAA (7.4% vs. 3.4%, p = 0.007). By 1-year post-diagnosis, 3970 (91.3%) and 2576 (59.3%) children had echocardiography and cardiology follow-up, respectively.

Conclusions — KD incidence is increasing in Ontario, with greater healthcare utilization from hospitalizations and subsequent follow-up.

Impact — 4346 children were hospitalized for Kawasaki disease over 22 years in Ontario, and Kawasaki disease incidence increased significantly for all age groups, males and females. Older children (10-18 years) had longer hospital length of stay, more PICU admissions and more frequent coronary artery aneurysms. Nearly all children with Kawasaki disease had follow-up echocardiography within 1 year.