KD is the main vasculitis affecting children < 5 years and the leading cause of acquired heart disease in children. Its epidemiology is few reported in France. Even if IVIG is still the standard treatment; the management of patients at risk for cardiac complications may change toward reinforced (and new) therapeutic approaches. Kawanet is a clinical and biological data repository aimed to define the epidemiological characteristics of KD in France.
Methods: Institutional physicians received information on a national registry for KD. All patients suspected with KD and seen since 2011 were eligible to enter the study. An eCRF was implemented in a web database.The included patients without the AHA international criteria were reviewed by an experts' committee.
Results: 468 cases were entered by 84 physicians from 65 centers. The AHA classification gave: 280 complete KD, and 73 incomplete KD. An expert consensus classified 48 other patients as probable leading to 401 patients considered as KD (M229/F72). 67 were excluded (incomplete data or doubful). The median age at diagnosis was 3.1y (2m-14y). Their ethnical backgrounds were: European Caucasian 67%, Eastern Caucasian/North African 15%, afro-Caribbean 13%, Asian 4% and mixed ancestry 1%. The clinical symptoms were (%): conjunctivitis 84, cheilitis 82, diffuse exanthema 74, modification of the extremities 73, oral erythema 66, cervical adenopathy 52, raspberry tongue 49, seat erythema 26, perineal desquamation 18 and BCG erythema 5. The cardiac complications were: coronary dilatation 30%, pericarditis 15%, coronary aneurysm 4%, and myocarditis 3% (1 death). 392/401 (98%) patients received IVIG, 64 (21%) and 5 required 2 and 3 courses. The mean treatment delay was 6 days. The factors associated with the coronary abnormalities were: male gender (p=0.01), young KD onset age (p=0.03), and resistance to IVIG (p=0.03).
conclusion: KD diagnosis remains challenging and overdiagnosis represents at least 10% of cases in this registry. Incomplete forms of KD account for 37 % and are associated with coronary dilatation/aneurysm (34%; p<0.01) and a high rate of IVIG resistance. Unlike previous studies, our population is very mixed with 28 % of children from the Middle East and Africa, in whom KD is still few reported.