Background — Kawasaki disease (KD) incidence is increasing in Ontario. Cardiovascular sequelae following KD are well-described. However, there are limited data on non-cardiovascular outcomes.
Objectives — To determine the risk of hearing loss, anxiety, developmental disorders, intellectual disabilities and attention-deficit/hyperactivity disorder (ADHD) among KD survivors vs. non-exposed children.
Methods — We included all Ontario children (≤18 yr) surviving hospitalization with a KD diagnosis between 1995 and 2018, using population-based health administrative databases. We excluded children with prior KD diagnoses and non-residents. KD cases were matched with 100 non-exposed children by age, sex and year. Follow-up continued until death or March 2019. We calculated the prevalence, incidence and adjusted hazard ratios (aHR [95%CI]) of outcomes between 0–1 yr, 1–5 yr, 5–10 yr and >10 yr follow-up.
Results — Among 4597 KD survivors, 364 (7.9%) were diagnosed with hearing loss, 1213 (26.4%) anxiety disorders, 398 (8.7%) developmental disorders, 51 (1.1%) intellectual disability and 21 (0.5%) ADHD, during median 11 year follow-up. Compared to 459,700 non-exposed children, KD survivors were not at increased risk of hearing loss after adjustment for potential confounders. KD survivors were at increased risk of anxiety disorders between 0–1 yr (aHR 1.75 [1.46–2.10]), 1–5 yr (aHR 1.13 [1.01–1.28]), 5–10 yr (aHR 1.14 [1.03–1.28]) and >10 yr (aHR 1.11 [1.02–1.22]); developmental disorders between 0–1 yr (aHR 1.49 [1.28–1.74]) and 1–5 yr (aHR 1.19 [1.02–1.40]); intellectual disabilities >10 yr (aHR 2.36 [1.36–4.10]); and ADHD >10 yr (aHR 2.01 [1.14–3.57]).
Conclusions — KD survivors are at increased risk of being diagnosed with anxiety disorders sooner, being diagnosed with developmental disorders between 0 and 5 yr and being diagnosed with intellectual disabilities or ADHD >10 yr after KD diagnosis. This may justify enhanced developmental and audiological surveillance of KD survivors.